INTERNATIONAL ROAD MAINTENANCE HANDBOOK PRACTICAL GUIDELINES FOR RURAL ROAD MAINTENANCE Volume I of IV Roadside Areas and Drainage Financed and coordinated by Revised by R C Petts of Intech Associates, UK with the financial support of ODA under assignment to TRANSPORT RESEARCH LABORATORY, UK as a development of the UN ECA handbooks prepared by joint cooperation of the governments of FRANCE, GERMANY and the UNITED KINGDOM and first published in 1982. ©WORLD COPYRIGHT RESERVED 1994 Extracts from the text may be reproduced provided the source is acknowledged as follows. PIARC Road Maintenance Handbook English version published by Transport Research Laboratory, UK ISRN by complete set of 4 Volumes: 0 9521860 12 I5BN for Volume I: 0 952186020 FOREWORD The road transport network of any country plays a vital role in its economy, and the physical condition of its infrastructure is critical. Without adequate and timely maintenance, highways and rural roads alike inexorably deteriorate, leading to higher vehicle operating costs, increased numbers of accidents, and reduced reliability of transport services. When repair work can no longer be delayed it will often involve extensive rehabilitation, and even reconstruction, costing many times more than simpler maintenance treatment carried out earlier. The need to protect the existing network and keep it in good condition is paramount, often taking precedence over new investment. PIARC has been in the forefront in promoting this message and in drawing attention to the dangers of neglect. The matter has become increasingly important in recent years for all the highways of the world, but especially so for those in developing countries where there is constant pressure on slender budgets and, in many, an urgent need to cater for growing traffic loads and volumes. In the late 1970's, the aid ministries of France, the Federal Republic of Germany and the United Kingdom joined forces to produce a “Road Maintenance Handbook” for maintenance foremen and workers in Africa. Published in 1982 under the auspices of the Economic Commission for Africa, the three volumes - in French and English - soon became widely known and used. By the end of the decade their use had spread far beyond Africa, and their straightforward instructions were being used for training purposes as well as for I-I FOREWORD continued on-the-job guidance in many countries. The need to reprint provided the opportunity to review the contents in the light of experience and make them more suitable for the wider audience now commanded. PIARC's Committee on Technology Transfer and Development, formerly the Committee on Roads in Developing Regions, undertook to help with this review, which was generously funded by the UK Overseas Development Administration. A sub-committee was established, embracing the three original donor countries, other developed and developing countries, and the World Bank. Although much of the original text has been retained, the new handbooks incorporate more information on labour and tractor-based techniques, and on the development of manpower management and the all-important question of safety at work. The range of maintenance problems addressed has been extended to strengthen their international appeal. The past ten years have seen major reforms in the general thrust of maintenance policy and in its organisation, management and execution. These changes will continue, and PIARC will play its part along with other institutions in encouraging the process and pressing for further progress. Only a full appreciation of maintenance at the highest levels of policy-making and financial planning can ensure success. But these handbooks have a humbler task-to ensure that the men and women at the operational level are suitably skilled and trained and are using the appropriate tools and techniques, and have interest and motivation in their work. I – ii FOREWORD continued PIARC has been proud to nurture this project to the point where the new handbooks are available, but its involvement will reach far beyond that. It will provide the necessary international framework within which the handbooks can be translated and printed in many languages. Its worldwide membership of key figures in the national provision and management of highways will assist with their dissemination, ensuring that they find their way into the most appropriate hands in both the public and private sectors. Collectively, these hands will play a fundamental part in sustaining the vital asset which our roadway networks truly represent. Victor J Mahbub, President of PIARC. I - iii CONTENTS FOREWORD i INTRODUCTION x Part A - LIST OF TERMS 1 ROAD CROSS SECTION 2 DRAINAGE FEATURES 3 GLOSSARY OF TERMS 4 General Terms 6 Components of the Highway 7 Defects 13 Drainage 16 Maintenance Activities 20 Maintenance Plant and Equipment 23 Materials 27 Survey Terms 30 I - iv CONTENTS CONTINUED Part B - WORKS MANAGEMENT AND SAFETY 33 GENERAL 34 SAFETY 35 MANPOW ER 37 ORGANISATION 38 I-v CONTENTS CONTINUED Part C - ROAD SIDE AREAS 41 1.THE TASK 43 1.1 SHOULDERS 47 1.2 SLOPES 49 2.DEFECTS 51 2.1 LISTOFDEFECTS 51 2.2 SHOULDERS 53 2.3 SLOPES 61 3.RESOURCES 67 3.1 PERSONNEL 69 3.2 PLANT AND TOOLS 71 3.3 MATERIALS 77 3.4 SIGNS AND SAFETY EQUIPMENT 79 4. MAINTENANCE METHOD 83 4.1 PRELIMINARY TASKS 83 4.2 TEMPORARY SIGNPOSTING 89 4.3 EXECUTION OF THE WORK 93 4.4 COMPLETION AND REMOVAL OF TEMPORARY SIGNS 143 4.5 WORK REPORT 147 5.RESOURCES 151 5.1 PERSONNEL 151 5.2 PLANT AND TOOLS 153 5.3 MATERIALS 155 5.4 SIGNS AND SAFETY EQUIPMENT 157 I - vi CONTENTS CONTINUED Part C - ROAD SIDE AREAS CONTINUED6. MAINTENANCE METHOD 159 6.1 PRELIMINARY TASKS 159 6.2 EXECUTION OF THE WORK 161 I - vii CONTENTS CONTINUED Part D - DRAINAGE 163 1.THE TASK 165 1.1 OBJECTIVE 169 1.2 ACTIVITIES 171 2.DEFECTS 175 2.1 LISTOFDEFECTS 175 2.2 DITCHES AND DRAINS 177 2.3 CULVERTS 187 2.4 DRIFTS AND CAUSEW AYS 195 2.5 MANHOLES AND DRAINAGE PIPES 199 3.RESOURCES 203 3.1 PERSONNEL 205 3.2 PLANT AND TOOLS 207 3.3 MATERIALS 211 3.4 SIGNS AND SAFETY EQUIPMENT 213 4. MAINTENANCE METHOD 215 4.1 PRELIMINARY TASKS 215 4.2 TEMPORARY SIGNPOSTING 219 4.3 EXECUTION OF THE WORK 221 4.4 COMPLETION AND REMOVAL OF TEMPORARY SIGNS 283 4.5 WORK REPORT 287 5. RESOURCES 291 5.1 PERSONNEL 291 5.2 PLANT AND TOOLS 293 5.3 MATERIALS 295 5.4 SIGNS AND SAFETY EQUIPMENT 295 I-viii CONTENTS CONTINUED Part D - DRAINAGE 163 1.THE TASK 165 1.1 OBJECTIVE 169 1.2 ACTIVITIES 1712.DEFECTS 175 2.1 LISTOFDEFECTS 175 2.2 DITCHES AND DRAINS 177 2.3 CULVERTS 187 2.4 DRIFTS AND CAUSEW AYS 195 2.5 MANHOLES AND DRAINAGE PIPES 199 3.RESOURCES 203 3.1 PERSONNEL 205 3.2 PLANT AND TOOLS 207 3.3 MATERIALS 211 3.4 SIGNS AND SAFETY EQUIPMENT 213 4. MAINTENANCE METHOD 215 4.1 PRELIMINARY TASKS 215 4.2 TEMPORARY SIGNPOSTING 219 4.3 EXECUTION OF THE WORK 221 4.4 COMPLETION AND REMOVAL OF TEMPORARY SIGNS 283 4.5 WORK REPORT 287 5. RESOURCES 291 5.1 PERSONNEL 291 5.2 PLANT AND TOOLS 293 5.3 MATERIALS 295 5.4 SIGNS AND SAFETY EQUIPMENT 295 I-viii CONTENTS CONTINUED Part D - DRAINAGE CONTINUED 6. MAINTENANCE METHOD 2976.1 PRELIMINARY TASKS 297 6.2 EXECUTION OF THE WORK 299 GENERAL INDEX 303 I – ix INTRODUCTION THE HANDBOOK This is a guide for the maintenance foreman or supervisor assigned to bitumen or unpaved roads in tropical and moderate climates. The objective of the HANDBOOK is to assist him in all aspects of his work whether carried out by direct labour or by contract. Its pocket format enables the volume relevant to the day's work to be easily carried and consulted on site. The HANDBOOK should be his ready reference book. The text is concise and well illustrated. A quick reference should be all that is necessary. This HANDBOOK does not include a course of study or discuss underlying causes of defects. Inspections, material sources, specifications and testing are also outside its scope. Furthermore it is sufficient here to remind the foreman that his plant and vehicles should be well maintained without telling him how to do it. Even though the HANDBOOK is intended for use by the maintenance foreman, it will also be useful reading for the engineer or senior supervisor. This will make him more conscious of his duties towards the foreman and enable him to ensure that the maximum benefit is obtained from the HANDBOOK. Each supervisor must understand his responsibility and the part he has to play. The HANDBOOK can also be used in training centres. With the assistance of country-specific supplementary information, photographic slides, models, and other supporting material, it will be a valuable tool for the trainer and can be distributed to students. I - x Road maintenance requires a range of organisational and technical skills and the work on roads in use by traffic makes the work potentially hazardous to both the workmen and road users. It is therefore essential that appropriate formal and on-the-job training is given to each category of personnel involved in road maintenance activities to achieve efficient and safe operations. The foreman usually has an important role in the initial and ongoing training of personnel. Roads are an enormous national investment and require maintenance to keep them in a satisfactory condition and ensure safe passage at an appropriate speed and with low road user costs. Late or insufficient maintenance will increase the ultimate repair costs and raise road user costs and inconvenience, and reduce safety. Road Maintenance is therefore an essential function and should be carried out on a timely basis. There is a diversity of maintenance activities, the class and type of the road, the cross section to be maintained, the defects recognised, and the resources available. However the general methods proposed here for each activity (with some exceptions) are given under the following headings: - The task - Defects - Resources - Maintenance method I - xi Where appropriate options are shown for carrying out the work by: I) Heavy Equipment, ii)Tractor based methods, or iii) Labour based methods. The decision on which method to be used should be made by the engineer or senior supervisor based on considerations of resources available, cost, policy etc. Maintenance operations are usually grouped in each country according to planning, organisational and funding arrangements. They can normally be categorised as either ROUTINE or PERIODIC. For the purposes of this HANDBOOK the following grouping is used. ROUTINE: Operations required to be carried out once or more peryear on a section of road. These operations are typically small scale or simple, but widely dispersed, and require skilled or un-skilled manpower. The need for these can, to a degree, be estimated and planned and can sometimes be carried out on a regular basis. PERIODIC: Operations that are occasionally required on a section of road after a period of a number of years. They are normally large scale and require specialist equipment and skilled resources. These operations are costly and require specific identification and planning. In this I – xii handbook periodic also includes certain Improvemnt works such as thin bituminous overlays. From time to time urgent or emergency works of any nature may be required and these are dealt with as the need arises. The HANDBOOK consists of 4 separate volumes: VOLUME I - MAINTENANCE OF ROADSIDE AREAS AND DRAINAGE PART A - List of Terms PART B - Works Management and Safety PART C - Roadside Areas PART D - Drainage General Index VOLUME II- MAINTENANCE OF UNPAVED ROADS PART A - Grading PART B - Labour Based Reshaping PART C - Dragging PART D - Patching PART E - Regravelling (Mechanised) PART F - Regravelling (Labour and Tractors) VOLUME III- MAINTENANCE OF PAVED ROADS PART A - General Repairs PART B - Surface Dressing (Mechanised) PART C - Resealing Options PART D - Thin Overlays I - xiii VOLUME IV - MAINTENANCE OF STRUCTURES AND TRAFFIC CONTROL DEVICES PART A - Bridges PART B - Traffic Control Devices VOLUME I PART A - LIST OF TERMS This volume provides a List of Terms used in the Handbook and an Index covering all of the four volumes. PART B - WORKS MANAGEMENT AND SAFETY General guidelines are provided regarding management and safety of the maintenance operations. This volume also describes the maintenance of roadside areas and drainage. Although generally straight forward these operations are often neglected. They are, however, important and have the following objectives: •To minimise the safety risk to road users due to poor shoulders and slopes, poor visibility, grazing animals or fire hazard etc. • To ensure the stability of the road foundations. • To ensure that all rain and ground water is directed away from the road, and does not endanger its strength or stability. I - xiv PART C - ROADSIDE AREAS Routine and Periodic Maintenance activities are described which keep the roadside areas in their intended and stable condition, and keep vegetation under control. Most of the tasks require labour, although some may be carried out by mechanised methods if the equipment is available. PART D - DRAINAGE The drainage system is the most important component of a highway or rural road, even in locations with only occasional rainfall. The Routine Maintenance of the drainage system of ditches, pipe drains, culverts and drifts is essential to preserve the road structure and running surface. Most of the activities can be carried out by labour methods. NOTE: In many countries women carry out road maintenance tasks and supervisory duties. The use of male descriptions and diagrams in this handbook is for convenience only. The guidelines are applicable whether the work is carried out or supervised by men or women. I – xv Part ALIST OF TERMS NOTE: ROAD CROSS SECTION, DRAINAGE FEATURES AND OTHER TERMS ARE INDICATED IN THE TEXT OF EACH VOLUME BY AN ASTERISK (*) PART A-LIST OF TERMS ROAD CROSS SECTIONS PAVED ROAD SECTION UNPAVED ROAD SECTION NOT TO SCALE 1. SUBGRADE 13. ORIGINAL GROUND LEVEL 2. ROADWAY 14. CUTTING SLOPE 3. CARRIAGEWAY 15. EMBANKMENT SLOPE 4. SHOULDER 16. DITCH INSIDE SLOPE 5. CAMBER/CROSSFALL 17. DITCH OUTSIDE SLOPE 6. SURFACING 18. DITCH INVERT 7. ROADBASE 19. ROAD CENTRELINE 8. SUB-BASE 20. GRAVEL SURFACE (WHERE 9. PAVEMENT CONSTRUCTED) 10. EMBANKMENT 21. V-DITCH 11 CUTTING 22. TRAPEZOIDAL DITCH 12. SUBGRADE SURFACE /FORMATION NOTE: Ditch shape according to conditions and maintenance method 1-2 PART A - LIST OF TERMS DRAINAGE FEATURES I-3 PART A- LIST OF TERMS GLOSSARY OF TERMS Page Page 4WD 23 Abney Level 30 Aggregate Silo (Hopper) 23 Aggregate 27 Aggregate Brooming 20 Alligator Cracks 13 Apron 16 Asphalt 27 Asphaltic Concrete 27 Attendant or Lengthman 20 Basin 16 Berm 16 Bitumen Heater-Distributer Truck 23 Bituminous Binder, Asphalt 27 Bituminous Slurry (Slurry-Seal) 27 Bleeding 13 Blinding 7 Block Cracking 13 Bridge 7 Camber 7 Camber Board 30 Carriageway 8 Cascade 16 Catchpit 16 Catchwater Drain 17 Causeway or Vented Drift 8 Chippings 28 Chute 16 Coffer Dam 8 Compaction 20 Counterfort Drain 17 Cracking 13 Crazing 13 Cribwork 28 Crown 5 Culvert 8 Cut (Cutting) 9 Page Pag Cut-off/Catchwater Drain 17 Debris Rack or Grill 17 Deck 9 Depression 13 Ditch (Drain) 17 Drag 23 Drainage 17 Drainage Pipe 17 Drift or Ford 9 EdgeCracking 13 Embankment 9 Excess Aggregate 14 Flow Spreader 18 FogSeal 20 Formation 9 Fretting 14 Gabion 28 Glazing 14 Gritter 23 Hoist 24 Hopper 24 Invert 18 Layby 9 Lengthman 20 Loss of Surface Aggregate 14 Manhole 18 Margins 10 Mechanical Broom 24 Mitre Drain 18 Mixing Plant 24 Outfall 18 Parapet 10 Pass 20 Patching 20 Patching Vehicle 24 Paved Road 6 Pavement 10 Paver-Screed-Plate 25 Periodic Maintenance 21 I - 4 PART A - LIST OF TERMS GLOSSARY OF TERMS CONTINUED Page Permeable Soils 18 Plumbing 30 Profile 30 Ramps 25 Ravelling 15 Riprap 19 Roadbase and Subbase 10 Road Maintenance 21 Road Paver Adjusting-Blocks 25 Road Paver 25 Roadway 10 Routine Maintenance 21 Sand Mixtures 28 Sanding 21 Scarifying 22 Scour 14 Scour Checks 19 Scuppers 10 Shoulder 11 Slip 14 Slope 11 Slot 30 Slurry Seal 22 Sod 28 Soffit 19 Spray Lance 25 Squeegee 26 Streaking 15 Stringer 11 Stripping 15 Subbase 10 Subgrade 11 Subsoil Drainage 19 Surfacing 11 Surface Treatment 11 Surface Dressing 22 Tar Binder 28 Template 31 TorqueWrench 26 TraflicLane 12 Transverse Joint 12 Transverse Joint Taper 12 Traveller 31 Turf 29 Underdrainage (Sub-Soil Drainage) 19 Unpaved Road 6 Urgent Maintenance 22 Vented Drift 8 Weephole 19 Windrow 22 Wingwall 12 I – 5 PART A - LIST OF TERMS GENERAL TERMS Paved Road For the purpose of this handbook a paved road is a road with a bituminous surfacing. Unpaved Road For the purpose of this handbook an unpaved road is a road with a soil or gravel surface. I - 6 PART A- LIST OF TERMS COMPONENTS OF THE HIGHWAY Blinding a) A layer of lean concrete, usually 5 to 10 cm thick,placed on soil to seal it and provide a clean and level working surface to build the foundations of a wall, or any other structure. b) An application of fine material e.g. sand, to fill voids in the surface of a pavement or earthworks layer. Bridge A structure usually with a span of 5 metres or more, providing a means of crossing above water, a railway or another obstruction, whether natural or artificial. A bridge consists of abutments, deck and sometimes wingwalls and piers. Camber The road surface is normally shaped to fall away from the centre line to either side. The camber is necessary to shed rain water and reduce the risk of passing vehicles colliding. The slope of the camber is called the crossfall. On sharp bends the road surface should fall directly from the outside of the bend to the inside. I -7 PART A - LIST OF TERMS Carriageway The road pavement or bridge deck surface on which vehicles travel. Causeway or Vented Drift Low level structure constructed across streams or rivers with openings to permit water to pass below road level. The causeway may become submerged in flood conditions. Coffer Dam A temporary dam built above the ground to give access to an area which is normally, or has a risk of being, submerged or waterlogged. Cofferdams may be constructed of soil, sandbags or sheetpiles. Crown The highest point of the cross section of the road carriageway, usually the centre line. Culvert A structure allowing water to flow under the road and having an open span of normally between 0.5 and about 5 metres. The opening may be round, rectangular or arched. The invert, walls and soffit often form an integral unit. I - 8 PART A- LIST OF TERMS Cut (Cutting) Excavation in natural ground usually with graded slopes. Deck The part of a bridge that spans between abutments or pier supports, and carries the road traffic. Drift or Ford A stream or river crossing at bed level over which the stream or river water can flow. Embankment Constructed earthworks below the pavement raising the road above the surrounding natural ground level. Formation The shaped surface of the earthworks, or subgrade, before constructing the pavement layers. Layby An area adjacent to the road for the temporary parking of vehicles. I - 9 PART A - LIST OF TERMS Margins The right of way or land area maintained or owned by the road authority. Parapet The protective edge, barrer, wall or railing at the edge of a bridge deck. Pavement The constructed layers of the road on which the vehicles travel. Roadbase and Subbase Pavement courses between surfacing and subgrade. Roadway The portion of a highway, including shoulders, for vehicular use. Scuppers Drainage pipes or outlets in a bridge deck. I - 10 PART A- LIST OF TERMS Shoulder Paved or unpaved part of the highway next to the outer edge of the pavement. The shoulder provides side support for the pavement and allows vehicles to stop or pass in an emergency. Slope A natural or artificially constructed soil surface at an angle to the horizontal. Stringer Longitudinal beam in a bridge deck or structure. Subgrade Upper layer of the natural or imported soil (free of unsuitable material) which supports the pavement. Surfacing Top layer of the pavement. Consists of wearing course, and sometimes a base course or binder course. Surface Treatment Construction of a protective surface layer e.g. by spray application of a bituminous or tar binder, blinded with coated or uncoated aggregate. I – 11 PART A - LIST OF TERMS Traffic Lane The portion of the carriageway defined by road markings for the movement of a single line of vehicles. Transverse Joint Joint normal to, or at an angle to, the road centre line. Transverse Joint Taper Slope or ramp of premix material at the end of a freshly laid premix course. Wingwall Retaining wall at a bridge abutment to retain and protect the embankment fill behind the abutment. I – 12 PART A- LIST OF TERMS DEFECTS Bleeding Excess binder on the surface of the pavement. Block Cracking Interconnected cracks forming a series of large polygons usually with sharp corners or angles. Cracking Narrow breaks in a surfacing or pavement material caused by overloading, fatigue or weakness of the material. Crazing (Alligator Cracks) Interconnecting network of cracks in the road surfacing. Depression Localised low areas of limited size in the pavement surface or in any other surface. Edge Cracking Longitudinal cracking near the edge of the pavement. I – 13 PART A- LIST OF TERMS Excess Aggregate Aggregate particles not coated with binder after application of binder. Fretting The loss of chippings from the surface seal or premix layer due to poor bond between the aggregate and the seal or binder. Glazing Wear or embedment of chippings in the surfacing giving a smooth, shiny appearance. Loss of Surface Aggregate Removal of aggregate from a surface dressing, or from surfacings with coated aggregate. Scour Erosion of a channel bed area by water in motion, producing a deepening or widening of the channel. Slip Slope material sliding downhill because of instability, water penetration or flow. I – 14 PART A- LIST OF TERMS Streaking Alternate lean and heavy lines of bitumen running parallel to the pavement centre tine, caused by blocked or incorrectly set spray nozzles. Stripping (Ravelling) The loss of surface seal from the pavement due to poor bond between the seal and the lower pavement layer. I – 15 PART A- LIST OF TERMS DRAINAGE Apron The flat invert of the culvert inlet or outlet. Basin A structure at a culvert inlet or outlet to contain turbulence and prevent erosion. Berm A low ridge or bund of soil to collect or redirect surface water Cascade A drainage channel with a series of steps, sometimes with intermediate silt traps or ponds, to take water down a steep slope. Catchpit A manhole or open structure with a sump to collect silt. Chute An inclined pipe, drain or channel constructed in or on a slope. I – 16 PART A LIST OF TERMS Counterfort Drain A drain running down a slope and excavated into it. The excavation is partly or completely filled with free draining material to allow ground water to escape. Cut-off/Catchwater Drain A ditch constructed uphill from a cutting face to intercept surface water flowing towards the road. Debris Rack or Grill Grill, grid or post structure located near a culvert entrance to hold back floating debris too large to pass through the culvert. Ditch (Drain) A long narrow excavation designed or intended to collect and drain off surface water. Drainage Interception and removal of ground water and surface water by artificial or natural means. Drainage Pipe An underground pipe to carry water. I – 17 PART A-LIST OF TERMS Flow Spreader A structure designed to disperse the flow at the outfall of a ditch or drain to minimise the risk of erosion down stream. Invert The lowest point of the internal cross-section of a ditch or culvert Manhole Accessible pit with a cover forming part of the drainage system and permitting inspection and maintenance of underground drainage pipes. Mitre Drain Or Turn Out Drain, leads water away from the Side Drains to the adjoining land. Outfall Discharge end of a ditch or culvert. Permeable Soils Soils through which water will drain easily e.g. sandy soils. Clays are generally impermeable except when cracked or fissured. I – 18 PART A - LIST OF TERMS Riprap Stones, usually between 5 to 50 kg, used to protect the banks or bed of a river or watercourse from scour. Scour Checks Small checks in a ditch or drain to reduce water velocity and reduce the possibility of erosion. Soffit The highest point in the internal cross-section of a culvert, or the underside of a bridge deck. Underdrainage (Sub-Soil Drainage) System of pervious pipes or free draining material, designed to collect and carry water in the ground. Weephole Opening provided in retaining walls or bridge abutments to permit drainage of water in the filter layer or soil layer behind the structure. They prevent water pressure building up behind the structure. I – 19 PART A- LIST OF TERMS MAINTENANCE ACTIVITIES Aggregate Brooming Using a broom to spread chippings on a surface. Attendant or Lengthman A person contracted to maintain a section of road. Can be male or female and the term "Attendant" or "Lengthman" assumes either sex. Compaction Reduction in bulk of fill or other material by rolling or tamping. Fog Seal A very light film of binder sprayed onto a road to bind or enrich the surface. Pass A single longitudinal traverse made by a grader, roller or other piece of equipment working on the road. Patching The execution of minor local repairs to the pavement and shoulders. I – 20 PART A – LIST OF TERMS Periodic Maintenance Operations that are occasionally required on a section of road after a period of a number of years. They are normally large scale and require specialist equipment and skilled resources to implement, and usually necessitate the temporary deployment of those resources on the road section. These operations are costly and require specific identification and planning for implementation, and often require design. Road Maintenance Suitable routine, periodic and urgent activities to keep pavement, shoulders, slopes, drainage facilities and all other structures and property within the road margins as near as possible to their as-constructed or renewed condition. Maintenance includes minor repairs and improvements to eliminate the cause of defects and avoid excessive repetition of maintenance efforts. Routine Maintenance Operations required to be carried out once or more per year on a section of road. These operations are typically small scale or simple, but widely dispersed, and require skilled or un-skilled manpower. The need for some of these can be estimated and planned on a regular basis e.g. vegetation control. Sanding Spreading course sand onto a bituminous road surface that is bleeding. I - 21 PART A - LIST OF TERMS Scarifying The systematic disruption and loosening of the top of a road or layer surface by mechanical or other means. Slurry Seal A mixture usually containing fine graded aggregates, water, bitumen emulsion, cement and sometimes an additive, spread on the road surface by a specially equipped machine, or by hand. Surface Dressing A sprayed or hand applied film of bitumen followed by the application of a layer of stone chippings, which is then rolled. Urgent Maintenance Certain unforeseen situations necessitating remedial action to be taken as soon as possible, e.g. flood damage, slips. Wind row A ridge of material formed by the spillage from the end of the machine blade. I – 22 PART A - LIST OF TERMS MAINTENANCE PLANT AND EQUIPMENT 4WD Four Wheel Drive vehicle or equipment. Aggregate Silo (Hopper) Storage container for aggregate which is fed from the top and emptied from the bottom. Bitumen Heater-Distributer Truck A truck with an insulated tank and heating system, designed to apply a bituminous binder at an even and uniform rate of spread. Drag An apparatus towed behind a vehicle or piece of equipment to remove minor irregularities and redistribute loose surface material. Gritter A self propelled machine or an apparatus fitted to the back of a tipper truck, to spread chippings in a controlled and constant rate of spread. I - 23 PART A - LIST OF TERMS Hoist A hydraulic, mechanically or manually operated lifting device. Hopper The body of a road paving machine into which the premixed materials are tipped prior to spreading. Mechanical Broom Motor-operated rotary broom used to sweep loose material and objects from the pavement surface, usually attached to a tractor. Mixing Plant Mechanical plant designed to grade and mix mineral aggregates and binder to produce premix material. Patching Vehicle A specialist truck equipped with a bitumen tank of about 2000 litres capacity, with or without heater, cover for personnel, hopper for aggregate, and hand- spray lance. I - 24 PART A- LIST OF TERMS Paver-Screed-Plate A levelling device with a flat bottom mounted at the rear of the paver, which strikes off the fresh premix at the desired thickness and provides some initial compaction to the mix. Ramps Timber or steel planks for loading and unloading small items of equipment. Road Paver A self-propelled or tractor-drawn machine designed to evenly spread and partially compact aggregate mixtures. Road Paver Adjusting-Blocks Wooden blocks of the same thickness as the uncompacted premix mat, which are placed under the screed plate before spreading starts in order to adjust the thickness control. When starting from a previously laid mat, the block thickness equals the difference between the loose mat thickness and the rolled mat thickness. Spray Lance Apparatus permitting hand-application of bituminous binder at a desired rate of spread through a nozzle. I - 25 PART A-LIST OF TERMS Squeegee A small wooden or metal board with a handle for spreading bituminous mixtures by hand. Torque Wrench A spanner or wrench with a mechanism to indicate or yield when a pre-set torque is applied. I – 26 PART A - LIST OF TERMS MATERIALS Aggregate Hard mineral elements of construction material mixtures, for example: sand, gravel, crushed rock. Asphalt Sometimes used to describe plant mixed bituminous materials. See also Bituminous Binder. Asphaltic Concrete A high quality manufactured mixture of bitumen and aggregates. Bituminous Slurry (Slurry-Seal) Mixture, usually of fine-grained aggregates, water, bituminous binder (emulsion), cement, and sometimes an additive, for a road surface seal. Bituminous Binder, Asphalt A petroleum oil based or natural product used to bind or coat aggregates for road pavements. I – 27 PART A - LIST OF TERMS Chippings Clean, strong, durable pieces of stone made by crushing or napping rock. The chippings are screened to obtain material in a small size range. Cribwork Timber or reinforced concrete beams laid in an interlocking grid, and filled with soil to form a retaining wall. Gabion Stone-filled wire or steel mesh cage. Gabions are often used as retaining walls or river bank scour protection structures. Sand Mixtures Sands of different gradings, mixed to provide the required material for a bituminous mixture. Sod As Turf but with more soil attached (usually more than 10 cms). Tar Binder A binder made from processing coal. I – 28 PART A – LIST OF TERMS Turf A grass turf is formed by excavating an area of live grass and lifting the grass complete with about 5 cms of topsoil and roots still attached. I - 29 PART A - LIST OF TERMS SURVEY TERMS Abney Level Small hand held slope measuring and levelling equipment. Camber Board Apparatus for checking the crossfall of the road camber, or the shoulder. Plumbing Using a calibrated line, with a weight attached to the bottom, to measure the depth of water. Profile An adjustable board attached to a ranging rod for setting out. Slot A sample cross section of the road or drain constructed as a guide for following earthworks or reshaping. I - 30 PART A - LIST OF TERMS Template A thin board or timber pattern used to check the shape of an excavation. Traveller A rod or pole of fixed length (e.g. 1 metre) used for sighting between profile boards for setting out levels and grades. I - 31 I - 32 Part B WORKS MANAGEMENT AND SAFETY I – 33 PART B - WORKS MANAGEMENT AND SAFETY GENERAL The maintenance foreman or supervisor has an important role in the road maintenance operations. He is the road authority's or contractor's representative most in contact with the actual works. He is usually responsible for the day to day scheduling of work, organising the resources, arranging safety measures, directing and controlling the work and preparing basic reports of the work carried out. The maintenance foreman or supervisor must have and display qualities of: - Responsibility - Experience - Consciousness - Impartiality and honesty in his dealings with labour, artisans and operators under his responsibility, and his supervisors. This Part of the handbook provides some general guidelines on management for road maintenance foremen and supervisors. I - 34 PART B - WORKS MANAGEMENT AND SAFETY SAFETY Many Road maintenance operations are potentially dangerous, both to the maintenance workers and to the road users. It is the responsibility of the maintenance foreman or supervisor to insist that all risks are minimised by: ¯ ensuring that the necessary temporary traffic signs and protection are provided and correctly located on site for the duration of the works. Where necessary, traffic should be stopped during the placement or removal of temporary signs, ¯ arranging for safety vests and helmets to be worn in appropriate circumstances, e.g. when working on the carriageways or shoulders, or on bridges, ¯ ensuring that all plant and vehicles are parked off the carriageway or behind protective barriers and signs, when not in use, ¯ ensuring that no materials are left in a dangerous location and that the road adjacent to the worksite is kept clean and swept of any debris arising from the maintenance work, ¯ ensuring that proper precautions are taken when handling dangerous substances e.g hot bitumen, corrosive or poisonous substances, I - 35 PART B - WORKS MANAGEMENT AND SAFETY ¯ ensuring that all excavations are protected for the benefit of all road users, equipment and workers, ¯ ensuring that all operators are trained in the operation of their equipment. If they are not adequately trained when they are assigned to the foreman or supervisor, he should himself provide, or arrange for, the necessary instruction. Operators and labourers alike must be informed of the potential risks of and procedures for working with or close to machinery, ¯ ensuring that traffic control operations are properly carried out and that road users are not unnecessarily delayed, ¯ ensuring all ladders or scaffolding used in bridge maintenance are securely fixed, ¯ ensuring that where work on the carriageway or shoulder remains unfinished overnight, then proper warning lights are arranged and, if necessary, protected, ¯ ensuring that all sites are left tidy and cleared of debris when the work is completed. I - 36 PART B - WORKS MANAGEMENT AND SAFETY MANPOWER This is the vital resource, whether operating machines or using handtools, for the success of the road maintenance operations. A well motivated workforce will perform many times better than an unmotivated one. The foreman or supervisor must play his part in motivating the workforce by: ¯ being firm and fair in all his dealings with the workforce, ¯ scheduling and organising the work so that it is efficiently carried out, ¯ arranging a fair workload for each member of the workforce, ¯ discussing and trying to resolve work and personnel problems as they arise, ¯ encouraging good quality work from the workforce and care of the equipment and handtools, ¯ ensuring that each member of the workforce is trained and able to carry out his allocated task. The foreman or supervisor should carry out or arrange any necessary initial or refresher training, ¯ ensuring that payment arrangements are timely, complete and correct. I - 37 PART B - WORKS MANAGEMENT AND SAFETY ORGANISATION The maintenance foreman or supervisor should schedule and organise work according to the Worksheet or other instructions. Equipment and handtools should be arranged as necessary to carry out the task. Mechanical support arrangements will be necessary for sophisticated equipment or items working away from the base for extended periods. Fuel, lubricants, consumable spares, and daily servicing must be ensured to keep equipment operational. Handtools should be of construction quality with proper handles; not merely tree branches cut and formed on site. Good quality handtools can significantly improve productivity and minimise injuries. Arrangements should be made to repair or replace worn or broken handtools. Materials should be arranged and transported to site. They should comply with the specifications and be tested when necessary. The signs and safety equipment should be arranged according to the guidelines or requirements. The foreman or supervisor should ensure that equipment items are not misused. Work may be carried out by a mobile gang, a gang located or recruited in the locality of the work and walking or cycling to work, or by individual attendants or lengthmen. I - 38 PART B - WORKS MANAGEMENT AND SAFETY Daily tasks or targets should be used wherever possible. These work outputs should be developed from local experience. Ideally the workforce should be released for the day once their task has been achieved with regard to quantity and satisfactory quality. Dayworks arrangements, whereby a worker stays for a set time period, usually achieves lower productivity. This arrangement should be avoided wherever possible. Gangs, attendants or lengthmen may be set weekly or fortnightly tasks where supervision arrangements allow only infrequent visits for instruction and inspection. The work should be recorded on the appropriate forms as accurately as possible. This helps to monitor the progress of the work and plan for future maintenance operations. The foreman or supervisor is the "eyes and ears" of the Engineer, who necessarily can only make infrequent visits to the site. The foreman or supervisor should keep the engineer fully informed of progress on site and any problems encountered. Finally it must be emphasised that the work of the foreman or supervisor is practically orientated. Most of his time should be spent on site organising and controlling work and solving the problems that occur there. Time spent in the office should be minimised, to carry out the necessary arrangements for support, administration, payments and reporting. I - 39 I – 40 Part C ROAD SIDE AREAS I – 41 PART C - ROADSIDE AREAS 1. THE TASK ■ Roadside Areas include the shoulders* and sideslopes, and all surface areas within the road rnargins* maintained by the Road Authority, except the carriageway* Although these areas are normally not used by traffic, their maintenance contributes to the safety of road users and stability of the road. ■ Roadside Areas maintenance is normally a ROUTINE* activity although occasionally some PERIODIC* maintenance activities are required. See List of Terms, Volume I I – 43 PART C - ROADSIDE AREAS ■ Most Roadside Areas maintenance activities can be achieved by labour, and are suitable for being carried out by a mobile or local gang, or by an individual attendant or lengthman living close to the road. ■ Roadside Areas consist of: ¯ shoulders of paved roads, ¯ slopes and other surface areas within the road margin. Paved shoulders and laybys* are treated as paved* roads. Their maintenance is described in Volume Ill of the Handbook. * See List of Terms, Volume I I – 45 PART C - ROADSIDE AREAS 1.1 SHOULDERS ■ The OBJECT of shouIder* maintenance is to retain the shape and levels of the shoulder, so that: ¯ the road pavement* has adequate side support, ¯ traffic can safely use the shoulder in an emergency, ¯ water drains from the carriageway* to the roadside ditch. ■ Shoulder maintenance consists of the following activities Routine* Activities REMOVING OBSTRUCTIONS RESHAPING SHOULDERS VEGETATION CONTROL Periodic* Activities ADDING SHOULDER MATERIAL * See List of Terms, Volume I. I – 47 PART C - ROADSIDE AREAS 1.2 SLOPES ■ The OBJECT of maintenance of slopes and other roadside areas is to ensure that: ¯ the slopes are protected against the potential erosion forces of water, and to retain their shape and stability, ¯ the safety risk to road users is minimised due to poor visibility, grazing animals or fire hazard. ■ Maintenance of Slopes and other roadside areas consists of the following activities: Routine* Activities VEGETATION CONTROL Periodic* Activities EROSION CONTROL SLIP REPAIR * See List of Terms, Volume L I –49 PART C – ROADSIDE AREAS 2. DEFECTS 2.1 LIST OF DEFECTS On the following pages commonly occurring defects are shown. Their probable causes are given together with a suggested maintenance activity. In addition the results of neglected repair are mentioned: ■ Defect ■ Main causes of the defect ■ Development: consequences if maintenance is not rapidly carried out, ■ Remedies : usual repair treatments. I – 51 PART C - ROADSIDE AREAS 2.2 SHOULDERS DEFECT: OBSTRUCTIONS ON SHOULDER* Rocks, trees or tree branches, soil heaps, wind blown sand, abandoned vehicles/debris. Main Causes - material fallen from slopes or trees, material blown - or washed onto the shoulders, - debris left by road users. Development, if neglected - hazard to road users, - obstruction of water flow from carriageway*. Remedies - remove obstructions and dispose of safely. * See List of Terms, Volume I. I – 53 PART C – ROADSIDE AREAS SHOULDERS DEFECT: SHOULDER HIGHER THAN CARRIAGEWAY, SHOULDER MISSHAPED Main Causes ¯ carriageway* surface material has collected on the shoulder by the action of traffic/water, ¯ soil from the cutting has slipped onto the shoulder, ¯ vegetation has trapped material on the shoulder, ¯ shoulder material has been displaced by the action of traffic. Development, if neglected ¯ surface water can pond at the edge of the carriageway and weaken the pavement and shoulder*, ¯ danger of accidents, ¯ the roadside ditch may become blocked by the excess material. Remedies ¯ reshape or regrade shoulder surface to the correct level, ¯ vegetation control. * See List of Terms, Volume I. I – 55 PART C-ROADSIDE AREAS SHOULDERS DEFECT: SHOULDER LOWER THAN CARRIAGEWAY, RUTS OR DEPRESSIONS Main Causes ¯ traffic has been travelling on the sholder and material has been worn away, ¯ water erosion of the shoulder, ¯ settlement of the shoulder, ¯ the carriageway has been overlaid leaving the shoulder surface lower than the pavement*. Development, if neglected ¯ inadequate support for the road pavement, ¯ water collects and softens the shoulder and pavement* foundation, ¯ the edge of the pavement will break when vehicle wheels run over it, ¯ increased risk of accidents. Remedies ¯ add shoulder material. * See List of Terms, Volume I. I – 57 PART G - ROADSIDE AREAS SHOULDERS DEFECTS: HIGH VEGETATION ON SHOULDER Main Causes Grass, weeds, bushes or trees have been allowed to grow unchecked. Development, if neglected ¯ surface water can pond at the edge of the carrageway and weaken the pavement*, ¯ silt accumulates at the edge of the carriageway, ¯ the visibility for road users is reduced, with increased risk of accidents with persons or animals, ¯ increased fire hazard in the dry season. Remedies - vegetation control. * See List of Terms, Volume I. I – 59 PART C - ROADSIDE AREAS 2.3 SLOPES DEFECT: VEGETATION OVERGROWN ON SLOPES Main Causes ¯ insufficient grass cutting, bush clearing and tree trimming. Development, if neglected ¯ overgrown trees or branches can fall and block the carriageway*, ¯ visibility for road users is reduced, with increased risk of accidents with persons or animals, ¯ the vegetation can block the drainage system or prevent it being inspected or maintained, ¯ increased fire hazard in the dry season. Remedies ¯ vegetation control. * See List of Terms, Volume I. I – 61 PART C -ROADSIDE AREAS SLOPES DEFECT: SURFACE WATER EROSION Main Causes ¯ rainwater concentrated into channels at the top of the slope, ¯ lack of vegetation cover. Development, if neglected ¯ deep erosion of the slope, ¯ slips*, ¯ obstruction of roadside ditch or shoulder*. Remedies Erosion prevention or repair by means of: ¯ berm*, ¯ cut-off ditch for cuttings, ¯ kerb or channel drain and chute* for embankments, ¯ turfing, ¯ seeding, ¯ waffling, ¯ stone pitching. * See List of Terms, Volume L I – 63 PART C-ROADSIDE AREAS SLOPES DEFECT: EARTH SLIP Main Causes ¯ the slope was too steep for its height, and the soil, ¯ water penetrating the slope from above, ¯ ground water pressure or flow. Development, if neglected ¯ the soil in the slope may continue to move downwards, blocking/cutting the roadway, ¯ water in roadside ditches cannot flow and ponding will occur. Remedies Slip repair by means of: ¯ reducing slope angle, ¯ clearing slip material, ¯ surcharging the slope, ¯ gabjons*, ¯ cribwork, ¯ masonry retaining wall, ¯ concrete retaining wall. * See List of Terms, Volume L I – 65 PART C-ROADSIDE AREAS 3. RESOURCES The following recommendations relate to carrying out the work using a mobile gang. Where appropriate, options for equipment or labour methods are described. Reduced transport resources will be required if the work is carried out by a local gang, with labourers walking to and from work each day. The gang size and other resources will be varied depending on the type and number of activities, the quantity of work to be achieved, and the resources available. Many of the activities described can be carried out by an attendant or lengthman. This approach is described in Pages l –149 to I -161. I – 67 PART C - ROADSIDE AREAS 3.1 PERSONNEL From the following resources. ■ Supervisors ¯ 1 foreman or overseer visiting regularly, ¯ 1 headman for each 10 to 20 workmen. ■ Plant Operators and Drivers ¯ 1 light vehicle driver (for foreman or overseer) 1, ¯ 1 tipper/flat bed truck driver 2 , ¯ 1 tractor-mower driver 3, ¯ 1 tractor-trailer driver 4, ¯ 1 tractor driver and 1 towed grader operator, or 1 motorgrader operator 5, ¯ 1 water tanker driver5, ¯ 1 roller operator 5, ¯ 1 bulldozer operator 6, ¯ 1 loader operator 6, ¯ 2 additional tipper drivers 6, 1 If a light vehicle is used, 2 If a mobile gang is used, or for materials/debris transport, 3 If vegetation control is mechanised, 4 Alternative for transporting materials and shoulder gravel up to about 10 km, 5 If shoulder repairs are carried out by mechanised methods, 6 If slip repair and slope stabilisation are carried out by mechanised methods. I – 69 PART C -ROADSIDE AREAS ■ Workforce ¯ 1 to 2 masons, ¯ 10 to 20 workmen, ¯ 2 traffic controllers (when working on the shoulders). 3.2 PLANT AND TOOLS From the following resources. ¯ 1 light vehicle or motorcycle, ¯ 1 tipper/flatbed truck or tractor-trailer (part-time) 1, ¯ 1 tractor with mower or rotary brush cutter attachment 2 1 tractor and towed grader, or 1 motorgrader3, ¯ 1 roller 3, ¯ 1 water tanker 3 with water pump, ¯ 1 bull doze 1, ¯ 1 wheeled or racked loader 4, ¯ 2 additional tipper trucks 4, 1 For transporting mobile gang or transporting debris or materials, 2 If vegetation control is mechanised, 3 If shoulder repairs are carried out by mechanised methods, 4 If sip repair and slope stabilisation are carded out by mechanised methods. I – 71 PART C - ROADSIDE AREAS ■ Small items of Equipment 1 ¯ 1 slasher, sickle or scythe per workman, ¯ 1 rake or hayfork per workman, ¯ 1 bushknife per workman, ¯ 5 hoes for every 10 workmen, ¯ 5 shovels for every 10 workmen, ¯ 5 mattocks for every 10 workmen, ¯ 2 sledgehammers, ¯ 4 handrammers, ¯ 2 brooms, ¯ 2 pickaxes, ¯ 2 crowbars, ¯ 2 bow saws, ¯ 1 two-man saw, ¯ 2 brush hooks, ¯ 2 axes, ¯ 2 to 8 wheelbarrows, ¯ 2 files (for sharpening tools), ¯ 1 small vibrating roller or plate compactor, ¯ ropes for tree felling, ¯ 1 ladder for tree felling, ¯ handtools for retaining wall construction. 1 Depending on activities to be carried out. I – 73 PART C-ROADSIDE AREAS ■ Tool and supplies To check the finished shoulder crossfall* a camber board will be required, made from 20 mm treated plywood or hardwood to give a 1 in 20 (5%) slope. - lubricating oils for equpitment**, - setting out aids for retaining walls**. ■ Support** If mechanised methods are used for slip repair and slope stabilisation. A low loader will be required to transport some of the equipment items to and from the work site. * See List of Terms, Volume L ** If applicable. I – 75 PART C -ROADSIDE AREAS 3.3 MATERIALS 1 ■ Gravel obtained from a quarry or gravel pit for shoulder repairs must be of a quality that meets the Departmental Specifications and also be approved by the Maintenance Engineer. ■ A source of water will be needed as near as possible to the site for shoulder repairs. ■ Materials for retaining wall construction to according to Departmental designs and specifications: ¯ aggregates, sand, cement, ¯ masonry stone or brick, or blocks, ¯ gabion wire baskets, ¯ 3 mm binding wire, ¯ wooden stakes, ¯ gabion filling stone, ¯ cribwork* components(timber or concrete), ¯ sandbags 1 Depending on activities to be carried out. * See List of Terms Volume L. I - 77 PART C - ROADSIDE AREAS 3.4 SIGNS AND SAFETY EQUIPMENT When adding gravel to the shoulders or for slip repairs, the following items should be provided where possible 1. ■ Traffic Signs ¯ 2 Reversible "Stop/Go" signs, ¯ 2 "Speed Limit" signs (50 km/hr)*, ¯ 2 "Men Working” signs* ¯ 2 "No Overtaking" signs, ¯ I "Road Narrows From Right" sign, ¯ I "Road Narrows From Left" sign, ¯ 2 "End of Restriction" signs*. ■ Barriers ¯ 2 lane closure barriers. ■ Traffic Cones As many as are required; at least 10 will usually be needed. 1 For other Roadside Areas maintenance tasks, only the asterisked* items may be required. When carrying out dispersed tasks, the following additional signs may be required. ¯ 2 "Grading Shoulders" signs, ¯ 2 "Mowing" signs . I – 79 PART C - ROADSIDE AREAS • • • • Safety Equipment Use should be made of the following equipment for personnel and the different vehicles as far as possible: ¯ yellow/orange shoulder belts for the foreman, and the other workmen working on the shoulders, ¯ red and white striped marker boards attached to all vehicles and plant. I – 81 TYPICAL WORKSHEET ROADSIDE AREAS Worksheet No: Date: District Zone: Gang: Road No.: from to Location(s): Work to be carried out: Work to be completed by: (Date) Signed PART C - ROADSIDE AREAS METHOD A: MOBILE GANG 4. MAINTENANCE METHOD 4.1 PRELIMINARY TASKS ■ The Worksheet will indicate the location and extent of the work to be carried out and the time, equipment and personnel required for the job. I – 83 PART C - ROADSIDE AREAS Before setting out to start the job, a check should be made to ensure that everything needed is ready. ■ The Truck, tractor and trailer, or other plant must be fuelled, checked mechanically and have water and oil levels checked. ■ Traffic signs, barriers and cones must be obtained and loaded onto the truck or trailer, according to the task. I - 85 PART C - ROADSIDE AREAS ■ Tools and small equipment must be obtained and loaded onto the truck or trailer. The roller may be loaded with the help of ramps* or a hoist*. ■ Arrangements must be made for obtaining water for shoulder repairs. ■ Arrangements must be made to load gravel onto the truck or trailer either at the depot or at a quarry. * See List of Terms, Volume L I – 87 PART C - ROADSIDE AREAS METHOD A: MOBILE GANG 4.2 TEMPORARY SIGNPOSTING When adding gravel to the shoulders, or for slip repairs, warning signs, barriers and cones must be placed around the work area. Work should be carried out on one side of the road at a time, allowing traffic to pass on the other. Signs must be placed in the following order: ■ "Men Working" signs should be placed 200 metres in front of the work area. ■ "Road Narrows" signs should be placed 100 metres in front of the work area. ■ "Speed Limit" signs should be placed at the start of the work area. ■ Barriers should be placed at each end of the work area. ■ Cones should be placed in a taper at the approaches to the work area and at a maximum spacing of 10 metres along the middle of the road next to the work area. ■ "End of Restriction" signs should be placed 50 metres beyond the work area. I – 89 PART C - ROADSIDE AREAS ■ Traffic controllers should stand next to the barriers in the centre of the road to operate the reversible "Stop/Go" signs. The controller closest to the oncoming traffic should decide when to stop the flow and allow traffic to travel in the other direction. Traffic should be stopped in both directions when works vehicles enter, leave or turn at the worksite. On low-traffic roads or for other Roadside Area's tasks, the Maintenance Engineer may approve the use of a simpler system of traffic control: ¯ Only the "Men Working" and "End of Restriction" signs may be required for most Roadside Areas tasks, ¯ when reshaping the shoulders by motor or towed grader, "Grading Shoulders" signs should be placed alongside the "Men Working" signs, ¯ when grass cutting with a tractor, "Mowing" signs should be placed alongside the "Men Working" signs. I – 91 PART C - ROADSIDE AREAS METHOD A: MOBILE GANG 4.3 EXECUTION OF THE WORK Shoulders REMOVING OBSTRUCTIONS This is a Routine* activity. Obstructions such as rocks, fallen trees or branches, soil heaps, windblown sand, abandoned vehicles/debris, are a hazard to road users and may prevent the flow of water from the carriageway to the drainage system. These obstructions should be loaded onto a truck or trailer, or otherwise removed from the shoulder, and disposed of at a safe location. Materials can often be spread safely on adjacent slopes. This activity is often carried out in conjunction with other tasks. * See List of Terms, Volume L I – 93 PART C-ROADSIDEAREAS Shoulders RESHAPING SHOULDERS This is a Routine* activity, to repair high or mis-shaped shoulders. a) Mechanised Method The existing surface of the shoulder should be scarified* with the tines of a motor or towed grader. This will loosen the raised areas and allow the loosened material to key into any existing low areas. The shoulders should be reshaped to slightly above the final level and the correct crossfall using the motor or towed grader blade. Care must be taken not to damage the edge of the road pavement* with the blade. The cross fall of the uncompacted material should be checked with a camber board. Excess material and vegetation should be graded to the embankment side slope. In cuttings, excess material and vegetation should be graded into a windrow* for removal by wheelbarrow, tractor and trailer or truck. Material should not be deposited on the carriageway* or into the drainage ditch. * See List of Terms, Volume I. I – 95 PART C- ROADSIDE AREAS If the material is dry it should be sprinkled with water. The shoulder is then compacted using a self propelled, towed or pedestrian roller. The compacted surface should butt smoothly onto the road pavement*. Check the finished crossfall* with the camber board and repeat the reshaping if necessary. Brush all loose material and debris from the carrageway*. *See List of Terms, Volume 1 I - 97 PART C - ROADSIDE AREAS b) LabourMethod The low surfaces and all high material should be loosened with a pick axe or mattock. The shoulder should be reshaped to slightly above the final level and the correct crossfall using a shovel and rake. The crossfall of the uncompacted material should be checked with a camber board. Excess material should be spread over the embankment slope or transported by wheelbarrow to a convenient and safe dumping site. Material should not be deposited on the carriageway* or in the drainage ditch. If the material is dry it should be sprinkled with water. The shoulder is then compacted with hand rammers or a hand roller. The compacted surface should butt smoothly onto the road pavement*. Check the finished crossfall* with the camber board and repeat the reshaping if necessary. Brush all loose material and debris from the carriageway*. * See List of Terms, Volume I. I - 99 PART C-ROADSIDE AREAS Shoulders VEGETATION CONTROL This is a Routine* activity, involving control of grass, weeds, bush and trees. With the exception of arid areas, grass and weed cutting and bush clearing on shoulders* is a basic maintenance activity. It is carried out at least once a year after the rainy season, or more often where the climate causes vegetation to grow rapidly. Most of the activities required for this task may be carried out by an agricultural tractor equipped with a sicklebar mower, flail mower or rotary brush cutters. Alternatively all of the activities may be achieved using labour and handtools. ■ Grass Cutting and Bush Control. Grass, weeds and bush should be cut at least once a year after vegetation reaches full growth or according to local experience. a) Mechanised Method ¯ mow only on level ground, free from obstructions and debris, ¯ do not mow when grass is wet, if experience shows this to be unsatisfactory, ¯ mow all shoulder areas between pavement and edge of road side ditch. * See List of Terms, Volume L I – 101 PART C-ROADSIDE AREAS As an alternative to the tractor-drawn sickle-bar mower, a hand-guided sickle-bar power mower or power flail mower can be used. The hand-guided mower will have a lower output than the tractor-drawn equipment, but it has the advantage of being able to operate on slopes* of about 1 to 1.5. Where only small areas need to be mowed, a small rotary grass mower may be appropriate. ¯ part of the workforce should work well ahead of the mower, removing obstructions, debris and bush stems in the path of the mower which could damage sickle-bar cutters. Ditches should be cleared of all unnecessary vegetation including the areas around fixed traffic control devices, which cannot be cut by mower, ¯ the supervisor should mark out any areas on the inside of curves which extend behind the shoulder* and ditch, and where bush cutting is required to improve the line of sight for road users, ¯ bush and grass cuttings left behind machines should be removed from the shoulder. Rake these into stacks at short intervals and remove them well away from the roadside so that they cannot block the drainage ditches. Debris should not be burned causing a hazard to traffic or surrounding vegetation, * See List of Terms, Volume L I – 103 PART C - ROADSIDE AREAS The use of all mowing and cutting equipment is potentially hazardous. Particular care must be taken when using this equipment and clearing any blockages. b) Labour Method As an alternative to mowing and in areas inaccessible to power equipment, (especially ditch side-slopes or on other steep slopes), the vegetation should be trimmed by hand. Sickles, scythes, slashers, bushknives, axes, saws or similar handtools will be required. ■ Trees Dead or leaning trees within the right-of-way which may fall on the carriageway* or block the drainage* system, or block sight lines should be removed. The felling of trees, or the removal of large branches at heights of more than 2 metres above ground level can be hazardous. This work should only be carried out under expert supervision or by experienced workers. Trees should be felled using two-man saws or axes. Ladders should be used for climbing trees, and ropes should be used to restrain trees and control felling. Traffic should be halted when the tree is finally toppled. All debris should be removed and disposed of safely. * See List at Terms, Volume I. I – 105 PART C - ROADSIDE AREAS ■ Herbicides Herbicides (weed-killer) are chemical agents intended to destroy or reduce vegetation growth. It is not recommended that herbicides or any chemical methods be used to control roadside vegetation. Some reasons are: ¯ herbicides can cause pollution of crops, rivers and streams and drinking water supplies, ¯ herbicides are often dangerous to health, ¯ herbicides are expensive, and must often be imported, ¯ herbicides do not always produce satisfactory results. ■ Burning Do not burn roadside vegetation to control its growth or the debris from Vegetation Control activities. The results may be more harmful than desired: ¯ the fire could spread and destroy valuable vegetation (trees, grass), and traffic control devices, ¯ vegetation may grow faster after burning, ¯ smoke and flames blowing across the highway are dangerous for traffic. I – 107 PART C-ROADSIDE AREAS ShouldersADDING SHOULDER MATERIAL This is normally a Periodic* activity to repair shoulders that have settled, or been eroded by traffic and water. It is also required when an overlay is applied to the road pavement*. a) Mechanised Method The existing surface of the shoulder should be scarified* with the tines of a motor or towed grader. This will loosen the surface and allow a key for the added material. New shoulder material is oft-loaded or tipped onto the shoulder, allowing a small surplus to requirements. The added material should be shaped to slightly above the final level and the correct crossfall using the motor or towed grader blade. Care must be taken not to damage the edge of the road pavement* with the blade. See List of Terms, Volume 1 I – 109 PART C - ROADSIDE AREAS The crossfall of the uncompacted material should be checked with a camber board. Excess material should be graded to the embankment side slope. In cuttings, excess material should be graded into a windrow* for removal by wheelbarrow, tractor and trailer, or truck. Material should not be deposited on the carriageway or into the drainage ditch. If the material is dry it should be sprinkled with water. The shoulder is then compacted using a self propelled, towed or pedestrian roller. The compacted surface should butt smoothly onto the road pavement*. Check the finished crossfall with the camberboard and repeat the reshaping if necessary. Brush all loose material and debris from the carriageway. * See List of Terms, Volume J. I - 111 PART C-ROADSIDE AREAS b) Labour Method The existing surface of the shoulder should be loosened with a pickaxe or mattock to allow a key for the added material. New shoulder material is off-loaded or tipped onto the shoulder, allowing a small surplus to requirements. The added material should be shaped to slightly above the final level and the correct .crossfall using a shovel/hoe and rake. The crossfall of the uncompacted material should be checked with a camber board. Excess material should be collected and transported by wheelbarrow for use further along the shoulder or discarded safely by spreading over the embankment slope or at a convenient location. If the material is dry it should be sprinkled with water, using containers or a small water bowser. The shoulder should be compacted using a hand rammer or a hand roller. Check the work and clear debris as for the Mechanised Method. I - 113 PART C-ROADSIDE AREAS SlopesVEGETATION CONTROL This is a Routine* activity involving the control of grass, weeds, bush and trees. The activities involved are the same as for shoulders* (Page I - 101), however the frequency of vegetation control operations may be reduced. The principal objective will be to keep sight lines and the drainage system free of excess vegetation. * See List of Terms, Volume I. I – 115 PART C -ROADSIDE AREAS SlopesEROSION CONTROL This is a periodic* activity, although its requirement is usually very localised. Erosion is usually caused by rainwater concentration on the slopes or by lack of vegetation cover. A number of options can be used to prevent or repair erosion on slopes and other Roadside Areas: ¯ berm for cuttings, ¯ cutoff ditch for cuttings, ¯ kerb or channel drain for embankments, ¯ turfing, ¯ seeding, ¯ wattling, ¯ stone pitching. * See List of Terms, Volume L I – 117 PART C-ROADSIDE AREAS ■ Berms tor cuttings A soil berm or bund can be built by hand along the top of a cutting face to prevent surface water flowing over the cutting face. The berm should be located to lead all water to a safe location for discharge or dispersal. The berm may need to be seeded to encourage vegetation growth and stability. Soil should not be excavated where it will allow water to pond or to seep into the cutting. ■ Cut-off ditch for cuttings This produces the same effect as the berm, however it will probably suffer more erosion and therefore require more maintenance. A cut-off ditch is not suitable for permeable* soils. ¯ determine location and alignment of ditch from local inspection; not too close to the edge of the slope. Follow the natural contour of the hill as closely as possible but with enough grade to permit water to flow, ¯ excavate ditch to about 50 cm depth. The sides of the ditch must not be too steep, otherwise they will collapse into the ditch and cause a blockage. Excavated material should be spread on the downslope side, ¯ protect outfall* of ditch if erosion is likely, by use of turfing, wattling or stone pitching, ¯ check the ditch regularly in the rainy season so that any necessary corrections or repairs can be carried out immediately. * See List of Terms, Volume L I - 119 PART C - ROADSIDE AREAS ■ kerb or Channel drain, for embankments A kerb or channel drain may be built at the edge of the carriageway or the back of the shoulder. The kerb may be of dressed stone, precast or insitu concrete. If the gradient falls throughout the embankment the kerb or drain may discharge at the cut-fill location. If there is a low point on the embankment, a chute* or cascade* will be required to safely discharge the water down the slope. For further details See Page I - 247. * See List of Terms, Volume I I – 121 PART C - ROADSIDE AREAS ■ Turfing (grass sodding) This method is suitable when climate and soil conditions are favourable and when fresh grass sods* (soil clumps containing grass and its roots) are available. The general procedure is: ¯ prepare the area to be tunfed* to required levels and slopes, ¯ where no topsoil is present, haul suitable topsoil to site and spread evenly to a depth of not less than 5 cm. Water as required, ¯ cover the area with freshly cut sods without weeds. Sods are to have thickly matted roots which should not have dried out. Tamp sods with tamper or use hand roller. On slope use stakes to hold sods in position, ¯ water the turves at intervals until the grass takes hold. Other patterns of sodding are: ¯ spot sodding (sods spaced about 50 cm in holes deep enough to take sod and about 5 cm topsoil), ¯ trench sodding. Lay sods on 5 cm topsoil bed in parallel trenches. Trench spacing about 50 cm along contour or x-shaped pattern. * See List of Terms, Volume 1 . I – 123 PART C - ROADSIDE AREAS ■ Seeding Grass seeding will only be successful if climate and soil conditions are favourable. The best advice can be provided by the local department of agriculture on: ¯ topsoil required, ¯ seed type, rate of spread, ¯ fertilizer types, rate of spread, ¯ most favourable season and weather for seeding, ¯ other preparatory treatment of the soil (for example mixing-in ground limestone). Typical procedure: ¯ loosen the soil to a depth of 10 cm in the area to be seeded using rakes or similar tools, ¯ spread the topsoil to a depth of at least 5 cm, ¯ water the area to be seeded, ¯ apply fertilizer at the specified rate, ¯ apply ground limestone at the specified rate and mix-in, ¯ apply seeds by hand at the specified rate, ¯ lightly roll the seeded area within 24 hours using hand roller, only if the soil does not adhere to the roller, ¯ the seeded area should be watered as required until the grass has taken hold. I – 125 PART C-ROADSIDE AREAS ■ Wattling These are bundles of plant stems up to 3 m long, tied together and laid in shallow trenches, staked into position on contour lines (lines of the same height), or x - form lines. As with turfing and seeding, a favourable climate and soil conditions are essential for the successful use of wattling. Wattling helps to stabilize slopes, reduce surface erosion and provides a bench on which grass can become established. Plant stems which root easily are preferred. Advice on suitable plants and planting time should be obtained from the local department of agriculture. Typical procedure: ¯ cut wattling stems at suitable source and transport them to site immediately. Stems should not be allowed to dry ¯ out, tie bundles of stems 15 - 20 cm diameter, alternating the ends, ¯ excavate a trench in the slope along the desired line. The trench should be deep enough to accommodate tied wattling stems (this work can be completed beforehand), ¯ place wattling stems in trench and use stakes to fix them in position. Overlap bundles and stake through the overlaps, ¯ cover the wattling with topsoil and tamp them firmly in place, -watering may be necessary until the roots take hold. I – 127 PART C - ROADSIDE AREAS ■ Stone Pitching This work is generally limited to small but important areas, for example* or culverts. Any rough stone can be used for stone pitching or riprap. The size should be as uniform as possible and the individual stones should weigh 10 to 20 kg. Heavier stones are preferred if riprap* is not to be grouted. The slope* should not be steeper than 1 to 1.5. ¯ transport stone and materials and off load at site, ¯ compact the slope to the desired shape, ¯ lay the stones in one layer with close joints, starting at the bottom of the slope with the larger stones. Stones should be supported by soil, smaller stones may be used to help wedge them in place. Larger stones should be buried deeper so that the final top surface will be uniform. When the stone pitching is to be grouted: ¯ wet the stone as thoroughly as possible, ¯ grout the spaces between stones with a mortar (1 cement: 4 sand), ¯ brush surface of the stone pitching with a stiff broom, ¯ protect the work from the sun using sacks or similar material, and keep wet for at least 3 days after grouting. * See List of Terms, Volume L I – 129 PART C - ROADSIDE AREAS SlopesSLIP REPAIR AND SLOPE STABILISATION This is a periodic* or Urgent activity, although its requirement is usually very localised. Slips or slope instability are usually caused by adverse ground conditions or water or both. The remedial works should be specified by the Maintenance Engineer after an inspection of the site and the necessary investigations. Dealing with slips and unstable slopes is hazardous and particular care should be taken to safeguard manpower, equipment and the road users. The principal remedial options are: ¯ reducing slope angle, ¯ clearing slip material, ¯ surcharging the slope, ¯ gabions, ¯ cribwork, ¯ masonry retaining wall, ¯ concrete retaining wall. * See List of Terms, Volume I. I – 131 PART C-ROADSIDE AREAS ■ Reducing Slope Angle Where a cutting face has slipped, one option is to reduce the angle of at least the upper part of the slope. This will increase overall stability and help prevent further slips. It is often advisable to reduce the slope angle before clearing the existing slip material. Care must be taken in case further slippage occurs. A bulldozer may be used if there is access and little risk of causing further slips by this heavy piece of equipment. Alternatively labourers may excavate the material and transport it to a safe dumping site using wheelbarrows. I – 133 PARTC -ROADSIDE AREAS ■ Clearing Slip Material This is a hazardous activity and should be planned and executed carefully. The slip material should be excavated so that, at all times, the slip and embankment or cutting face are stable. Do not work under an overhanging slope as soil may suddenly slide again. Excavate soil to reduce the angle at the top of the slope before slip clearing, if possible or necessary. ¯ excavate all slipped soil from carrjageway*, shoulder* and ditch* by loader or by hand, ¯ load onto trucks, tractor and trailer or wheelbarrows and remove to suitable dump sites, ¯ do not excavate too deep and damage the road or shoulder surface when using a front-end loader, ¯ remove last layer of slipped soil from the shoulder or carriageway by hand, ¯ clear the ditch and regrade or reshape if necessary, ¯ tine grade the roadway shoulder area with motor or towed grader if available, or by hand, ¯ if the area requires to be protected from further slipping, the most suitable method can only be determined from site inspection. If flowing water or excessive moisture is encountered, then a drainage blanket of granular material, or pipes, should be laid before building any of the repair measures described on Pages I - 137 to I - 141. * See List of Terms, Volume I. I – 135 PART C -ROADSIDE AREAS ■ Surcharging the Slope A cutting slope with a wide verge at the base or an embankment slope, may be surcharged to stabilise a slip without removing it. This involves widening the base of the slope by placing material to resist further slipping. The material should be placed in layers of 15 - 20 cms by hand or machine, and compacted with a roller or by hand rammers. If water or moisture is suspected as a cause of the slip, a drainage blanket of granular material should be laid before placing the fill material. It may also be necessary to excavate counterfort* drains into the slip material to allow water to drain away from the slip face. Extreme care must be taken when carrying out this activity. The final earthworks should be shaped to shed rainwater, and planted if necessary. Certain trees can be planted which will develop root systems to stabilise the slope and reduce underground moisture. Advice should be sought from the local department of agriculture. * See List of Terms, Volume 1 I – 137 PART C -ROADSIDE AREAS ■ Gabions* A gabion retaining wall may be used to stabilise the base of a slope. The advantages are that the wall can be constructed with relatively unskilled labour, is free-draining and will be flexible enough to allow for further small slip movements. Recommendations for gabion construction are provided in Part A of Volume IV (Pages IV - 73 to IV - 75). ■ Cribwork* Retaining walls up to about 5 metres may be constructed using timber or reinforced concrete crib units. The interlocking crib units are laid on a firm foundation with the face sloping back at between 6 to 1 and 8 to 1. The units are fitted with soil (compacted with hand rammers) as the wall increases in height. Cribwork will also allow for further small slip movements and can be rebuilt if necessary. The design of the crib units and wall should be arranged by the Maintenance Engineer. * See List of Terms, Volume I I – 139 PART C - ROADSIDE AREAS ■ Masonry Retaining Wall Where there is a stable foundation, a masonry retaining wall may be constructed to retain the base of unstable slopes. Recommendations on masonry wall construction are provided in Part A of Volume IV (Pages IV - 65 to IV - 67). ■ Concrete Retaining Wall Where there is a stable foundation, a reinforced or unreinforced concrete retaining wall may be constructed to retain the base of unstable slopes. These walls may require specialist skills for design and construction not available in a maintenance department. These should be organised by the Maintenance Engineer. I – 141 PART C - ROADSIDE AREAS METHOD A: MOBILE GANG 4.4 COMPLETION AND REMOVAL OF TEMPORARYSIGNS ■ Load tools, equipment and unused materials back onto the truck or trailer. ■ Where they have been used remove the signs, cones and barriers and load them onto the truck or trailer in the following order: 1 "End of Restriction" signs, 2 Traffic cones, 3 "Speed Limit” signs, 4 Barriers, 5 "Road Narrows" signs, 6 "Men Working" signs. I - 143 PART C - ROADSIDE AREAS ■ Ensure that the site is left clean and tidy with no stockpiles of material left on the shoulder. ■ Move onto the next job. ■ Inspect traffic signs and clean if necessary. I – 145 TYPICAL WORK REPORT ROADSIDE AREAS Work Report No: Date: District: Gang Zone Road No Section: from km to km Location(s): WORK ACHIEVED: MANPOWER USED: Name Grade Hours worked Name Grade Hours worked Name Grade Hours worked EQUIPMENT USED: DIESEL USED: Hrs litres Hrs litres MATERIALS USED: COMMENTS: Foreman: PART C - ROADSIDE AREAS 4.5 WORK REPORT The report must be filled in each day, detailing: ■ the work carried out, ■ the resources used. I – 147 PART C – ROADSIDE AREAS METHOD B: LABOUR BASED In some road maintenance Systems an individual attendant or lengthman lives close to a road and is responsible for the ROUTINE MAINTENANCE activities on that road. The following activities are suitable for this method: REMOVING OBSTRUCTIONS RESHAPING SHOULDERS VEGETATION CONTROL (SHOULDERS AND SLOPES) Furthermore the following PERIODIC MAINTENANCE activities may be carried out by attendants: ADDING SHOULDER GRAVEL (small scale) EROSION CONTROL (certain techniques) I - 149 PART C-ROADSIDE AREAS METHOD B: LABOUR BASED 5. RESOURCES 5.1 PERSONNEL ■ Supervisor ¯ foreman or overseer visiting regularly. ■ Workforce ¯ attendant or lengthman. I – 151 PART C - ROADSIDE AREAS METHOD B: LABOUR BASED 5.2 PLANT AND TOOLS 1 ¯ 1 broom, ¯ 1 pickaxe, ¯ 1 shovel, ¯ 1 hoe or mattock, ¯ 1 rake, ¯ 1 hand rammer with metal shoe, ¯ 1 wheelbarrow, ¯ 1 bucket or watering can, ¯ 1 grass slasher, sickle or scythe, ¯ 1 bush knife or bush hook, ¯ 1 axe, ¯ 1 bowsaw, ¯ 1 file for sharpening tools. Depending on activities to be carried out. I – 153 PART C - ROADSIDE AREAS METHOD B: LABOUR BASED 5.3 MATERIALS ■ Gravel for patching shoulders should be obtained from the quarry by truck or tractor and trailer. This is most efficiently done when major regravelling works are being carried out in the area of the road. ■ The gravel should be stockpiled at convenient locations where shoulder repairs are expected for the attendant to use on his section of road. The stockpiles must not obstruct the road, the shoulder or the drainage system. ■ Where there is no space in the road reserve the stockpile should be placed downhill of a turnout drain to avoid blocking the drainage system. I – 155 PART C-ROADSIDE AREAS METHOD B: LABOUR BASED 5.4 SIGNS AND SAFETY EQUIPMENT When working on the shoulder the following should be provided. ■ Traffic Signs 2 "Men Working" signs, OR 2 yellow/orange flags for placing on the shoulder. ■ Clothing Yellow or orange coloured safety vest or safety harness to be worn by the attendant when working on the shoulder. I - 157 PART C-ROADSIDE AREAS METHOD B: LABOUR BASED 6. MAINTENANCE METHOD 6.1 PRELIMINARY TASKS ■ The handtools are assigned to the attendant who keeps them at his home for use as necessary. ■ The worksheet will indicate the location and extent of the work to be carried out and the time required for the job. I - 159 PART C - ROADSIDE AREAS METHOD B: LABOUR BASED 6.2 EXECUTION OF THE WORK ■ The attendant should use the wheelbarrow to carry the tools and safety items to the site. ■ The warning signs or flags must be placed either side of the worksite. ■ The attendant should use the wheelbarrow to transpont the gravel material from the stockpiles to the "Adding Shoulder Gravel" site. ■ The tasks should be carried out as described for the Mobile Gang. ■ The warning signs or flags must be removed after the work. ■ The work report must be filled in for each day's work. I – 161 I - 162 Part D DRAINAGE I - 163 PART D - DRAINAGE 1. THE TASK ■ The Drainage System consists of side drains*, mitre (turnout) drains*, cut-off drains*, drainage pipes*, manholes*, chutes*, cascades, culverts*, drifts* and subsoil* drains. The purpose of the system is to rapidly collect and conduct rain and ground water away from the road. Water can cause widespread damage to the road by weakening the pavement* or foundations, and erosion. The Drainage System is therefore the most important component of a highway or rural road, even in locations with only occasional rainfall. * See List of Terms, Volume I I – 165 PART D - DRAINAGE ■ The Routine Maintenance* of the drainage system is essential to preserve the road structure and running surface. Occasionally major repairs or improvements are required to be carried out under Periodic Maintenance*. ■ Most Drainage maintenance activities can be achieved by labour, and are suitable for being carried out by a mobile or local gang, or by an individual attendant or lengthman living close to the road. ■ For the descriptions in this Part D (Drainage), it is assumed that all vegetation has been removed from the area around drainage features to enable drainage maintenance to be carried out. Vegetation control tasks are described in Part C of this volume. * See List of Terms, Volume I I – 167 PART D – DRAINAGE 1.1 OBJECTIVE ■ Water can seriously damage any road It can ¯ erode soils, ¯ weaken pavements*, ¯ destroy shoulders* and slopes*, ¯ wash-out culverts*, embankments* and even bridges* The satisfactory operation of the drainage system is therefore a vital condition for a satisfactory road. ■ The OBJECT of maintenance is to ensure that drainage system elements remain free of obstructions, and retain their intended cross- sections and grades. They must function properly so that ¯ surface water and ¯ groundwater can drain freely and quickly away from the road or under the road. *See List of Terms, Volume I I – 169 PART D - DRAINAGE 1.2 ACTIVITIES 1.2.1 Ditches* and Drains* Routine* Activities ■ CLEARING AND CLEANING ■ RESHAPE/REGRADE/DEEPEN ■ EROSION CONTROL a) Regrade/Realign Drains b) Repair Lining c) Provide/Repair Scour Protection Periodic* Activities ■ PROVIDE NEW MITRE (TURNOUT) DRAIN ■ EROSION CONTROL a) (Re)Line Drain b) Construct Cascade/Catchpit c) Construct Flow Spreader 1.2.2 CuIverts* Routine Activities ■ CLEARING AND CLEANING ■ EROSION REPAIR ■ CRACKING REPAIR ■ HEADWALL/APRON REPAIR Periodic Activities ■ REPAIR OF INVERT ■ (RE)CONSTRUCT CULVERT AT CORRECT LEVEL AND FALL ■ CONSTRUCT OUTFALL BASIN* * See List of Terms, Volume I . I – 171 PART D - DRAINAGE 1.2.3 Drift* and Causeways* Routine* Activities ■ MINOR REPAIRS ■ GRADING/CLEARING ■ REPLACE GUIDE-POSTS 1 .2.4 ManhoIes* and Drainage Pipes* Routine Activities ■ CLEAR MANHOLE AND UNDERGROUND PIPES ■ REPLACE MANHOLE COVER OR GRATING ■ CLEAR MANHOLE AREA ■ CLEAN CATCHPIT SUMP Periodic Activities ■ RELAY DRAINAGE PIPE * See List of Terms, Volume I. I – 173 PART D - DRAINAGE 2 DEFECTS 2.1 LIST OF DEFECTS On the following pages commonly occurring defects are shown. Their probable causes are given together with a suggested maintenance activity. In addition the results of neglected repair are mentioned: ƒ Defect ƒ Main causes of the defect ƒ Development: consequences if maintenance is not rapidly carried out ƒ Remedies: usual repair treatments. I – 175 PART D - DRAINAGE 2.2 DITCHES* AND DRAINS* DEFECT: OBSTRUCTIONS Main Causes - vegetation growth, bushes, fallen trees, debris, loose silt, loose rocks. Development, if neglected - blockage of ditch. Remedies - clearing and cleaning. DEFECT: SILTING Main Causes lnvert* slope is too flat, the water cannot flow at sufficient speed. Development, if neglected: - Blockage of the ditch. Remedies - deepen ditch (desilting), and/or provide new mitre drains (turnouts), where deepening or turnouts are not possible because of topography, the construction of a new culvert* with a drop-inlet may be possible, in order to discharge water onto the other side of the road. * See List of Terms, Volume I. I – 177 PART D - DRAINAGE DEFECT: PONDING IN DITCH AND ON SHOULDER Main Causes - the ditch cross-section is too small, - the ditch gradient is too flat. Development, if neglected The shoulder material becomes soft and can easily erode. The pavement* can also be flooded and thereby weakened. Remedies - deepen ditch, - provide new mitre drain. DEFECT: DITCH CROSS-SECTION IS DESTROYED (UNLINED DITCH) Main Causes - vehicular or animal traffic, cave-in. Development, if neglected Partial silting will result if the ditch sides have collapsed. Erosion can start where water flow passes the blocked section. Remedies - reshape/regrade ditch, line drain. * See List of Terms, Volume I . I – 179 PART D - DRAINAGE DEFECT: INVERT* AND SIDES OF DITCH* ARE ERODED ƒ Main Causes Invert slope is too steep. ƒ Development, if neglected The water flows at high speed and starts eroding the soil. The ditch becomes deeper (ravine). The sides then cave-in, the road shoulder and even part of the carriageway* can be washed away. ƒ Remedies Erosion control: - Regrade/realign drains, - provide repair scour protection, - line drain slopes and invert, - construct cascade. * See List of Terms, Volume I I – 181 PART D-DRAINAGE DEFECT: DITCH* LINING IS DAMAGED ƒ Main Causes - poor construction workmanship, - soil settlement, erosion of soil under ditch lining, - poor alignment or sudden change in flow direction. ƒ Development, if neglected When flowing water reaches the soil protected by the lining,. erosion starts. The amount of soil washed away increases, the lining is further damaged by loss of support, leading to complete destruction of the lining. ƒ Remedies Erosion control: - repair lining, - realign drain. * See List of Terms, Volume l I – 183 PART D - DRAINAGE DEFECTS: EROSION AT DRAIN OUTFALL* Main Causes - flow too fast, - flow too concentrated, for the soil at the outfall to resist. Development, if neglected Erosion will continue back into the ditch and increase in the area of the outfall. The erosion may eventually threaten the road as well as the surrounding land. Remedies Reduce water flow and speed by: - realign drain to flatter gradient, - provide new mitre drain, upstream from existing. Reduce impact at outfall by: - construct cascade, - construct flow spreader. Erosion Control for the soil: - turfing, - wattling, - stone pitching. * See List of Terms, volume I I - 185 PART D - DRAINAGE 2.3 CULVERTS* DEFECT: SILTING, SANDING, BLOCKAGE BY DEBRIS Main Causes ¯ Invent* slope too flat, ¯ culvert constructed too low, so that material from the stream bed becomes deposited in the culvert, ¯ vegetation and floating debris carried by water have become lodged in the culvert. Development, if neglected The intended waterway opening will be so reduced that flood water cannot flow. It will back-up or pond on the upstream side of the culvert and may eventually over-flow the road embankment*. The road is then in danger of being washed away. Remedies ¯ clearing and cleaning, ¯ if floating debris is a problem, the provision of a debris rack* should be considered. If the culvert regularly silts up: ¯ reconstruct at correct level and fall. See List of Terms, Volume I. I – 187 PART D - DRAINAGE DEFECT: SETTLEMENT CRACKS Main Causes Settlement of soil below culvert*. Development, if neglected ¯ minor damage: If the settlement is minor, only light cracking will result in headwalls, wingwalls and the main structure. This will hardly affect the functioning of the structure, ¯ major damage: If the settlement is severe, it will cause large relative movement of culvert pipes so that embankment soil will enter through the cracks and block the culvert, or the culvert may collapse. The culvert must then be reconstructed. Remedies - cracking repair, - reconstruct at correct level and fall. * See List of Terms Volume I. I – 189 PART D - DRAINAGE DEFECT: THE STEEL CULVERT INVERT' IS DAMAGED BY RUST Main Causes ¯ poor quality galvanising or surface protection, ¯ protective surfacing worn away by water flow, ¯ weathering (after long service life). Development, if neglected Severe damage to structure invert, probable partial or complete collapse of the structure. Remedies ¯ repair of invert, ¯ reconstruct at correct level and fall. *See List of Terms, Volume I. I – 191 PART D - DRAINAGE DEFECT: EROSION OF STREAM BED AT CULVERT OUTLET Main Causes ¯ the culvert invert has been constructed too steep so that the water flows too fast, ¯ the culvert invert has been constructed too flat with an excessive drop at the outfall (these are design or construction mistakes). Development, if neglected The stream bed is washed away and a pool or ravine develops. The culvert downstream head and wingwalls* and even a section of the culvert and road embankment can collapse into the pool or ravine. Remedies ¯ erosion repair, ¯ construct outfall basin*. DEFECT: MINOR HEADWALL/APRON* DAMAGE Main Causes ¯ minor settlement, ¯ scour or erosion. Development, if neglected ¯ erosion at the headwall/apron, ¯ culvert blockage or collapse. Remedies ¯ headwall/apron repair. * See List of Terms, Volume I. I – 193 PART D - DRAINAGE 2.4 DRIFTS AND CAUSEWAYS* The surfaces of submersible crossings are often constructed as a concrete slab. There is a high risk of washouts and slab movement caused by the water turbulence. Routine* maintenance should correct any minor defects as they occur, to avoid later extensive and costly major works. The Routine* activities can include concrete or masonry repair, placing of gabions* and erosion protection of causeway* openings as in the case of culverts. DEFECT: MINOR DEFECTS Main Causes ¯ settlement of slab, ¯ erosion. Development, if neglected The cracks in the drift* structure spread and widen especially during the following flood season. Erosion will undermine the drift. The drift will break up. Remedies Minor repairs. * See List of Terms, Volume I. I – 195 PART D - DRAINAGE DEFECT: DRIFT* OR CAUSEWAY* IS COVERED WITH DEBRIS Main Causes Natural movement of river bed material by flowing water. Development, if neglected The limits of the paving cannot be seen; vehicles may drive onto loose river bed material at the edge of the drift and become damaged or immobilised. Remedies Grading/Clearing drift surface. The surface must be cleared of all loose material. DEFECT: GUIDE-POSTS (MARKERS) ARE MISSING OR DAMAGED Main Causes Accident, flood damage, vandalism. Development, if neglected When the drift or causeway becomes submerged during flood, the edge of the pavement cannot be seen. Vehicles can accidentally drive into deep water. Remedies Replace guideposts. *See List of Terms, Volume I I – 197 PART D - DRAINAGE 2.5 MANHOLES* AND DRAINAGE PIPES* DEFECT: WATER IS FLOWING UP AT MANHOLE Main CausesThe manhole or connected underground pipes are blocked and water cannot flow as intended. Development, if neglected ¯ flooding of road shoulder* or carriageway* ¯ drainage system becomes ineffective, danger of earth slip or weakening of pavement*. Remedies Clear manhole and underground pipes. DEFECT: MANHOLE COVER OR GRATING IS MISSING/DAMAGED Main Causes Accident, vandalism. Development, if neglected Open manholes become a danger to people and animals. Vegetation and debris have uncontrolled access and blockage can occur. Remedies Replace manhole cover or grating. * See List of Terms, Volume I. I – 199 PART D - DRAINAGE DEFECT: THE MANHOLE* IS COVERED WITH SOIL AND VEGETATION Main Causes Silting of the ground area at manhole; manhole cover level possibly set too low. Development, if neglected Possible blockage of the drainage system at the manhole, due to an undetected accumulation of silt in the manhole. Remedies Clear manhole area. DEFECT: THE CATCHPIT* SUMP IS COMPLETELY SILTED UP Main Causes Silt and debris collecting in the sump has not been removed sufficiently regularly. Development, if neglected Possible blockage of the drainage system at the catchpit, or down stream due to a build up of silt or debris. Remedies Clean catchpit sump. * See List of Terms, Volume I I – 201 PART D - DRAINAGE 3. RESOURCES The following recommendations relate to carrying out the work using a mobile gang. Where appropriate options for equipment or labour methods are described. Reduced transport resources will be required if the work is carried out by a local gang, with labourers walking to and from work each day. The gang size and other resources may be varied depending on the type and number of activities, the quantity of work to be achieved, and the resources available. Many of the activities described can be carried out by an attendant or lengthman. This approach is described in Pages I – 28 to I -299. I - 203 PART D - DRAINAGE 3.1 PERSONNEL From the following resources. ■ Supervisors ¯ 1 foreman or overseer visiting regularly, ¯ 1 headman for each 10 to 20 workmen. ■ Plant Operators and Drivers ¯ 1 light vehicle driver (for foreman or overseer) 1, ¯ 1 tipper/flat bed truck driver 2, ¯ 1 tractor-trailer driver 3, ¯ 1 tractor driver and 1 towed grader operator, or 1 ¯ motorgrader operator 4. ■ Workforce ¯ 1 to 2 masons, ¯ 10 to 20 workmen. 1 If a light vehicle is used. 2 (f B mobile gang is used, or for materials/debris transport. 3 Alternative for transporting materials up to about 10 km, or debris. 4 (f drains are cleared/reshaped by mechanical methods. I –205 PART D - DRAINAGE 3.2 PLANT AND TOOLS¯ 1 light vehicle or motorcycle, ¯ 1 tipper/flatbed truck or tractor-trailer (part-time) 1, ¯ 1 tractor and towed grader, or 1 motorgrader 2, ¯ 1 water pump 3, ¯ 1 hand winch 3. I For transporting mobile gang or transporting debris or materials. 2 If drain cleaning/reshaping is mechanised. 3 For culvert/pipe repair work. I – 207 PART D - DRAINAGE • • • • Small items of Equipment 1 ¯ 1 hoe for every workman, ¯ 1 shovel for every workman, ¯ 5 mattocks for every 10 workmen, ¯ 5 slashers, ¯ 5 rakes, ¯ 5 bushknives, ¯ 2 sledgehammers, ¯ 4 handrammers, ¯ 2 brooms, ¯ 2 pickaxes, ¯ 2 crowbars, ¯ 2 bow saws, ¯ 2 brush hooks, ¯ 2 axes, ¯ 5 wheelbarrows, ¯ carpenter's saws, ¯ 2 claw hammers, ¯ 2 mallets, ¯ 2 chisel sets, ¯ 2 files (for sharpening tools), ¯ 1 plate compactor, ¯ ropes for controlling culvert components, ¯ assorted nails and pegs, ¯ long handled shovel/spike for culvert cleaning, ¯ rods and fittings for clearing pipe drains, ¯ 5 buckets, ¯ manhole cover lifting keys, ¯ 1 spirit level, ¯ 1 line and level or abney level, ¯ 1 ditch template and spirit level, ¯ 5 ranging rods and profiles, ¯ 2 mason's hammers, ¯ 2 club hammers, ¯ 2 mason's chisels, ¯ 2 mason's trowels, ¯ 2 pointing trowels, ¯ 2 mason's floats, ¯ 2 straight edges (2 metre), ¯ 2 measuring tapes (30 metre), ¯ 2 folding rules (2 metre), ¯ 2 plumb bobs, ¯ 2 setting out strings, ¯ 2 hand brushes ¯ aggregate measuring box (equivalent to 1 bag of cement). I Depending on activities to be carried out. I – 209 PART D - DRAINAGE 3.3 MATERIALS 1 ■ A source of water will be needed as near as possible to the site for masonry repairs. ■ Materials for culvert, drift, manhole or pipe repairs, according to local construction methods: ¯ aggregates, sand, cement, ¯ plastic sheet to protect cement, ¯ masonry stone or brick or blocks, ¯ gabion wire baskets, ¯ 3 mm binding wire, ¯ wooden stakes, ¯ gabion filling stone, ¯ concrete culvert rings, ¯ corrugated steel culvert rings and fittings, ¯ drainage pipes, ¯ manhole covers, ¯ jute or plastic sacks for sandbags, ¯ drain lining tiles. 1 Depending on activities to be carried out *See List of Terms, Volume I. I – 211 PART D - DRAINAGE 3.4 SIGNS AND SAFETY EQUIPMENTDrainage activities do not usually involve work on, or the need to close, all or part of the road carriageway or shoulder. Where occasionally such works are required (e.g. relaying a cross culvert), then Signs and Safety Equipment suitable for Bridgeworks should be used (Volume IV, Part A, Pages IV - 27 to 29). I – 213 TYPICAL WORKSHEETDRAINAGE Worksheet No: Date: District: Zone: Gang: Road No from to Location(s): Work to be carried out: Work to be completed by: (Date) Signed: PART D - DRAINAGE METHOD A: MOBILE GANG 4. MAINTENANCE METHOD 4.1 PRELIMINARY TASKS ■ The Worksheet will indicate the location and extent of the work to be carried out and the time, equipment and personnel required for the job. I - 215 PART D - DRAINAGE Before setting out to start the job, a check should be made to ensure that everything needed is ready. ■ The Truck, tractor and trailer, or other plant must be fuelled, checked mechanically and have water and oil levels checked. ■ Traffic signs, barriers and cones must be obtained and loaded onto the truck or trailer, if work is required on the carriageway or shoulders. ■ Tools, small equipment and materials, must be obtained and loaded onto the truck or trailer. ■ Arrangements must be made for obtaining water for culvert or pipe repairs. I – 217 PART D - DRAINAGE METHOD A: MOBILE GANG 4.2 TEMPORARY SIGNPOSTING Where work is required on the road carriageway or shoulders, signs should be provided and placed according to the recommendations of Volume IV, Part A - Bridges, Pages IV - 35 to 37. I – 219 PART D - DRAINAGE METHOD A: MOBILE GANG 4.3 EXECUTION OF THE WORK Ditches and Drains CLEARING AND CLEANING This is a Routine* activity. The object is to remove all soil, high vegetation, materials and objects from the ditch* which could possibly interfere with water flow or cause an eventual blockage of the ditch. This can include for example, rocks, loose silt and sand, weeds, trees, bushes, including their roots, etc. Dispose of these materials well away from the roadside so that water flow will not be impeded and they will not fall or wash back into the drain. On unlined ditches a short grass cover can help to stabilise the invert* and sides of the drain. Therefore where a side drain is established to the correct depth and profile with grass cover and no erosion, it is advisable to merely cut the grass short. This will leave the roots in place to bind the surface together. *See List of Terms, Volume I. I – 221 PART D - DRAINAGE Ditches and Drains RESHAPE/REGRADE/DEEPENThis is a Routine* activity that can be carried out by labour methods. In some locations it may be carried out by mechanised methods. a)Labour Method The object is to remove material from the ditch to obtain the correct cross-section and grade. It is advisable to adopt a trapezoidal ditch shape when using labour methods. The excavation using a hoe/mattock and shovel is easier than for a V- shaped ditch. An added advantage is that the flat invert causes less concentration of water than a V- ditch. A ditch template* should be used to obtain the correct drain shape. ¯ using the template a 50 cm wide sIot* should be excavated to the correct ditch shape every 10 metres. The slots act as a guide for excavating the ditch to the correct shape, ¯ in flat areas, the gradient of the ditch should be checked using ranging rods and profiles or similar methods, to ensure that water will not pond. The levels at adjacent slots should be checked using a line and level or abney level*, and the level of the slot adjusted if necessary. *See List of Terms, Volume I. I – 223 PART D - DRAINAGE ¯ excavate all surplus material between the slots and to the correct shape with the aid of stringlines stretched between the slots. If necessary the intermediate invert levels can be checked using a traveller* sighted between the ranging rod profiles. ¯ material excavated from the drain must be removed and spread well clear of the drain so that it cannot later fall or wash back into the ditch. ¯ the shape can be checked during the excavation activity using the ditch template*. When excavating a completely new ditch it is preferable to split the task into two operations: i. cut the central rectangular shape and check with a template (INVERT). ii. cut the slopes and check with the full template (SLOPES). The alignment or route of the drain should be set out using stringlines and pegs. The ranging rods and profiles should be set up at the start and outfall* of the ditch. Intermediate profiles may be required on long ditches. The levels of intermediate slots can be determined using the traveller. *See List of Terms, Volume I. I –225 PART D – DRAINAGE b) Mechanised Method This activity is suggested where long sections of V- shaped ditches* are to be maintained and cleaned and where high daily outputs are possible. The activity may be carried out by a motor or towed grader. The grader should always work in the direction of water flow in the ditch. Case 1: When the grader can operate only on the shoulder* and in the ditch, but not beyond the ditch: ¯ start by grading the outside sIope* of the ditch, windrowing the soil to the bottom of the ditch between the rear wheels. (This can be repeated to obtain the desired depth of ditch), ¯ the second pass* cleans the invert* of the ditch by removing the windrow to the top of the ditch at road shoulder, ¯ the third pass is required to move the windrow material away from the shoulder ditch edge. THE MATERIAL MUST BE REMOVED FROM THE SITE. UNDER NO CIRCUMSTANCES IS THE MATERIAL TO BE SPREAD ONTHE ROAD. *See List of Terms, Volume I. I – 227 PART D - DRAINAGE ¯ on completion, the ditch should generally have a depth of 50 cm (minimum), which can be checked with a ranging rod and tape/rule, ¯ if necessary the grade of the ditch invert can be checked using the methods described in a) Labour Method (Page I - 223). Case 2: ¯ When the grader can operate beyond the ditch. Reverse the operations shown previously: ¯ grade the inside slope, windrowing material to the bottom of the ditch. Repeat as necessary to achieve the desired depth of ditch, ¯ remove the windrow material to the top of the outside slope, ¯ move windrow away from ditch edge and spread the material so that it will not wash back into the ditch, ¯ on completion, the ditch should have a depth of 50 cm (minimum), which can be checked with a ranging rod and tape/rule, ¯ if necessary the grade of the ditch invert can be checked using the methods as described in a) Labour Method (Page I - 223). I – 229 PART D - DRAINAGE Ditches and Drains EROSION CONTROLA number of Routine* activities are possible to prevent or repair erosion damage to ditches* and drains* Drain sections are often laid at a steep gradient or on sharp bends without erosion protection along or at the outfall of the drain. The following options should be considered: a) Regrade/Realign Drains b) Repair Lining c) Provide/Repair Scour Protection If these Routine * activities are inadequate, then consideration should be given to the periodic* activities described on Pages I - 241 to I - 247. *See List of Terms, Volume I I – 231 PART D - DRAINAGE a) Regrade/Realign Drain ¯ the drain* may be extended with a flat outfall to reduce the speed of the water when leaving the ditch. The gradient should ideally be between 2% and 5%, ¯ the drain could be realigned to follow the contour lines more closely, until a location is reached where it may safely discharge. Both of the above options should use the techniques described under Reshape/Regrade/Deepen Pages I - 223 to I - 229. Water cannot flow smoothly around sharp bends. The result is usually a collapse of drain sides. The following repair measures are suggested: ¯ relay drain sections to a smooth easy curve and grout smooth any open joints, or ¯ install special precast curved ditch sections. *See List of Terms, Volume I I – 233 PART D - DRAINAGE b) Repair Lining Ditches* lined with masonry or other material need repair when the lining is damaged. The cause of such damage is usually settlement of the supporting soil. The repair work is to be carried out as soon as possible as the ditch can be quickly destroyed if water can flow under or behind the lining. The procedure is: ¯ remove settled or damaged precast sections or loose stone blocks, ¯ compact the underlying soil, ¯ backfill with suitable material and compact to correct levels, ¯ replace the precast sections or blocks to the correct line and grade, bedding them on mortar (1 cement : 4 sand), ¯ grout up any open joints with mortar, ¯ remove all debris. *See List of Terms, Volume I. I – 235 PART D - DRAINAGE c) Provide/Repair Scour Protection Unlined ditches* may suffer from scour of the invert and sides. ¯ simple repairs may be achieved by fillin~ the affected areas with soil and ~ where climatic conditions are favourable. The turves will probably need to be pegged in place to retain them, and watered until established, ¯ simple scour checks may be constructed of wood or stones. Larger ones may be constructed of stone masonry, brick or concrete. They reduce the speed and erosion force of the water. They also hold back the silt carried by the water flow to provide a series of gently sloping sections of ditch separated by steps. The scour checks must not be too high otherwise water will be forced onto the surrounding ground, the shoulder* or the ~ The scour check construction should therefore be controlled with the aid of a template*. *See List of Terms, Volume I I – 237 PART D - DRAINAGE Scour checks should not be constructed on ditches with gradients of less than 4%. This will encourage too much silting of the drain and could lead to road damage. The gradient of the side drain should be checked with an abney level* or line and level to determine the requirements for scour checks. After the basic scour check has been constructed, an apron should be built immediately downstream either using stones or grass turves pinned to the ditch invert with wooden pegs. The apron will help resist the forces of the water flowing over the scour check. Grass sods should be placed against the upstream face of the scour check, to prevent water seeping through the scour check and to encourage the silting behind the scour check. The long term objective is to establish complete grass cover over the silted scour checks to stabilise them.¯ more substantial Erosion Control measures are described on Pages I - 245 to I - 247, ¯ turfing, wattling and stone pitching of slopes are described on Pages I - 123 to I - 129 and are options for protecting areas downstream from outfalIs. * See List of Terms, Volume I. I - 239 PART D - DRAINAGE Ditches and DrainsA number of Periodic* activities may be required to achieve more substantial or permanent repairs and improvements to Ditches* and Drains PROVIDE NEW MITRE DRAIN* (TURNOUT) EROSION CONTROL: a) (Re)Line Drain, b) Construct Cascade*, c) Construct Flow Spreader*. *See List of Terms, Volume I. I – 241 PART D – DRAINAGE Ditches and Drains PROVIDE NEW MITRE* (TURNOUT) DRAINWhere water ponds, or the side drain carries too much water or where erosion occurs, it may be possible to construct additional mitre drains (turnouts). Frequent mitre drains prevent water volumes from building up, and discharge water onto the surrounding land in small quantities, therefore reducing the risk of erosion. Mitre drains may be desirable at spacings of 20 metres on some gradients. If water cannot be discharged from a drain over a distance of 200 metres, consideration should be given to other options: ¯ line drain (Page I - 245), ¯ construct new cross culvert (Page I - 265), to relieve the water flow in the ditch/drain. *See List of Terms, Volume I I – 243 PART D - DRAINAGE Ditches and Drains EROSION CONTROLa) (Re)Line Drain* When an unlined drain is frequently damaged, a new lining can be provided. The lining may be constructed with masonry stone, brick, precast concrete tiles or completely precast drain units. The activity may also be required if an existing lining is substantially damaged by previous poor workmanship, settlement or erosion. The drain should be hand excavated to the larger cross section required, using the guidelines on Pages I - 223 to I - 225. After compaction of the earth profile with hand rammers, the stone or concrete panels should be bedded and jointed with mortar of 1 cement : 4 sand. *See List at Terms, Volume I I – 245 PART D - DRAINAGE b) Construct Cascade/Catchpit* Where large volumes of water are required to be taken down a slope, an unlined or lined ditch* will probably provide insufficient resistance to erosion. A cascade* should be constructed in place of the slope drain* or chute*. Alternatively a basin* or catchpit should be constructed at the base of a lined slope drain or chute. The cascade or basin will slow the flow of the water and trap silt to reduce the risk of erosion downstream. The cascade may be constructed of stone masonry, brick or concrete. A catchpit may be constructed at a point where a drain changes direction, to resist erosion forces. c) Construct Flow Spreader* Where a ditch must discharge onto a steep or fragile slope, the water flow may be dispersed by constructing a flow spreader. This will reduce the risk of erosion. The flow spreader may be constructed of stone masonry, brick or concrete. *See List of Terms, Volume I.I – 247 PART D - DRAINAGE CULVERTS* Routine* Activities CLEARING AND CLEANINGIn order to function properly, a culvert must retain the full opening over its complete length. In addition, the upstream approaches and the downstream area must be free of obstructions. Floating debris (tree branches, bushes, etc.) carried by water is a great danger to culverts. The debris may completely block the culvert inlet. The following Routine activities may be required: ¯ if debris racks* are already provided, these should be freed of all accumulated obstructions, ¯ sanding or silting of culverts, especially those with openings smaller than 1 metre, is a particular problem. These culverts can be cleaned by pulling a cable or rope through, to which is attached any suitable object (e.g. a bucket). Alternatively a long handled trowel and spike can be used. If the silting problem continues despite regular clearing, it may be necessary to reconstruct the culvert at a higher level or enlarge it (Page I - 265), ¯ material and debris from the culvert must be spread or dumped where they cannot cause an obstruction to water flow, preferably on the downstream side of the culvert, well away from the watercourse. *See List of Terms, Volume I I – 249 PART D - DRAINAGE Culverts EROSION REPAIR Major repairs are described under periodic* Activities (Pages I-259to1-269). Where only light erosion of the stream bed has taken place at the culvert* outlet proceed as follows: ¯ fill eroded area with stone blocks of about 30 cm size to produce a rough energy dissipator. The block pitching or riprap* should preferably extend beyond the eroded area. If larger stone sizes are available, these should also be used. In the dry season or when the water flow is light or non existent, the blocks can be grouted with a concrete mix (1 cement : 4 sand : 8 gravel). ¯ where stone is not available, logs can be used, lined across the stream bed and extending into the stream banks for anchorage. For additional stability use steel cramps to tie logs to one another. *See List of Terms, Volume I. I – 251 PART D - DRAINAGE ¯ jute (or plastic) sacks, filled with soil can also be used as an alternative to rock lining. The soil can be mixed with about 5% cement for extra stability, ¯ do not overfill sacks. Tie sacks either with soft galvanised wire or strong string so that they cannot open, even when roughly handled, ¯ lay sacks flat in layers, the sacks in one layer covering the joints in the layer below. I –253 PART D - DRAINAGE Culverts GRACKING REPAIR Cracks 1 in concrete or masonry are easily identified during low-water or dry periods. They should be repaired as soon as possible. Proceed as follows: ¯ clean out all cracks with brush and water. Remove old mortar from any damaged masonry joints and clean the joints, ¯ where compressed air is available, deposits in cracks can be more easily removed, ¯ wet the crack openings before filling with a mortar (1 cement : 4 sand), ¯ fill cracks with mortar, ¯ trowel the mortar smooth after the crack has been filled. 1 cracks in dry concrete structure surfaces may be more easily seen, if the surface is first dampened with water using a hand water sprayer or similar. I – 255 PART D - DRAINAGE Culverts HEADWALL/APRON REPAIR Where part or all of a masonry or brick headwall/apron* has been damaged by erosion or settlement, a repair should be carried out as soon as possible. The procedure is: ¯ remove settled or damaged section of the headwalilap ron, ¯ compact the underlying soil, ¯ rebuild the headwall or apron using similar materials to the original, ¯ grout up all joints with mortar (1 cement : 4 sand), ¯ when the walls are strong enough (after 2 or 3 days) backfill behind walls with soil, ¯ remove all debris. *See List of Terms, Volume I. I – 257 PART D - DRAINAGE CulvertsA number of periodic* activities may be required to achieve more substantial or permanent repairs and improvements to Culverts*: REPAIR OF INVERT* RECONSTRUCT CULVERT AT CORRECT LEVEL AND FALL CONSTRUCT OUTFALL BASIN* *See List of Terms, Volume I. I -259 PART D - DRAINAGE Culverts REPAIR OF INVERT Corrugated steel culverts* will corrode it the protective galvanising or coating is damaged. The lnverts* are particularly at risk from this type of damage. Carry out the repair when the surface rusting starts. Do not wait until holes appear in the steel. Start work after the invert has dried out (dry season work) and all debris has been removed. METHOD A: Painting with bitumen¯ remove any rust from steel sections as far as possible, using steel wire brush, or other suitable tool, ¯ heat straight run (penetration) bitumen in a suitable bitumen heater until pourable but preferably not heated to more than 100 C, ¯ apply a thick coat (3 - 4 mm) of bitumen over the lower half of the culvert. The bitumen can be poured and brushed well into the surface. Try to achieve as smooth a surface as possible, ¯ excess bitumen should not be left on the invert which might allow accumulation of water. Care must be taken when heating and handling the bitumen, protective gloves and clothing should be worn. *See List of Terms, Volume I I – 261 PART D – DRAINAGE METHOD B: CONCRETE LINING¯ remove any rust as previously, ¯ mark out the edges of the concrete slab along the inside walls of the culvert* using stringline or chalk line, ¯ pour concrete slab (1 cement : 2 sand : 4 gravel) of 10 cm minimum thickness over the complete length of the culvert invert*. The concrete surface should slope slightly to the centre line axis of the culvert and then be trowelled smooth, ¯ normally no steel bar reinforcement will be required, ¯ the inlet and outlet aprons are to be concreted as necessary to adjust for the new culvert invert levels. *See List of Terms Volume I I – 263 PART D - DRAINAGE Culverts (RE)CONSTRUCT CULVERT* AT CORRECT LEVEL AND FALLMany culverts are installed too low because the horizontal alignment of the road was given priority at design/construction stage. Where culverts are installed too low they, usually have very long outfalls which repeatedly silt up along with the culverts themselves. Besides requiring a high level of desilting and manpower input, the heaps of desilted material can take up valuable farming land and continue to increase in size. In these circumstances it is advisable to raise the level of the culvert by re-excavation and relaying. Furthermore culverts of inadequate diameter have sometimes been installed. Culverts of less than 60 cm opening are extremely difficult to desilt, and the preferred minimum size for ease of maintenance is 1 metre. In these situations consideration should be given to reconstructing the culvert at the correct level and grade, to a suitable diameter (60 cm or larger). *See List of Terms, Volume I I – 265 PART D - DRAINAGE Culverts that have collapsed or are beyond repair should also be reconstructed. Where erosion problems exist in the side drains this may be due to excessive water volume f!owing. Consideration should be given to constructing a new cross culvert to relieve the flow in the side drain. All new or reconstructed culverts should be built according to Road Department designs and specifications. The road level may need to be raised for a suitable distance either side of the new/reconstructed culvert to accommodate the raised soffit* of the culvert. *See List of Terms, Volume I.I – 267 PART D - DRAINAGE Culverts CONSTRUCT OUTFALL BASINIf a more substantial or permanent repair than described on Page I - 257 is required, a Basin* or Catchpit* structure should be constructed at the outfall of the culvert. The basin will reduce the energy in the water and allow it to flow downstream with less risk of erosion. The basin may be constructed of stone, brick or concrete. *See List of Terms, Volume I I –269 PART D - DRAINAGE Drifts* and Causeways* Routine* Activities MINOR REPAIRS In the case of paved fords (masonry, brick or concrete slab), cracks should be filled with a bituminous mortar. Before filling, remove all soil and sand and clean thoroughly with water. Refer to Volume III "Maintenance of Paved Roads", Crack Sealing (Page III - 57). Potholes should be broken out down to slab depth, cleaned and then filled with concrete (1 cement : 2 sand 4 gravel), mortared stone work or bricks as appropriate. Erosion cavities immediately upstream or downstream of the drift or causeway should be filled with large stones or rip rap. In the case of serious or recurring erosion, ~ mattresses should be laid on the bed of the watercourse with their top surface at the same level as, or slightly below the level of, the drift or causeway inverts*. *See List of Terms, Volume I I – 271 PART D - DRAINAGE Drifts* and Causeways* GRADING/CLEARINGWater will deposit silt, sand and debris on the drift* or causeway* from time to time, and in or against the causeway openings. This must be regularly removed to avoid danger to traffic and the risk of erosion at the drift or causeway. Material and debris should be removed by hand and disposed of well clear of, and downstream from, the crossing. A motor or towed grader may be used for clearing the paved surface, however the windrow must be spread clear and downstream of the crossing to allow the free passage of water. *See List of Terms, Volume I I – 273 PART D - DRAINAGE REPLACE GUIDE-POSTSMissing or damaged marker or guide-posts on drifts or causeways should be replaced as required before the flood season. Use steel pipe of suitable diameter and length and painted in black and white sections. ¯ examine the pipe sockets, remove water, sand, silt, loose mortar etc. if present. Socket depth should be at least 15 cm. Use mason's hammers and chisels to enlarge or deepen the hole if necessary, ¯ place the pipe in the socket and pack it if necessary to the correct position and height. Use a mortar (1 cement : 3 sand) to grout the space between pipe and socket wall, ¯ timber guide-posts are not recommended as they can easily break. However hardwood posts can be used if properly anchored in the socket (tight fit) so that they will not be washed away with the following flood. I – 275 PART D - DRAINAGE ManhoIes* and Drainage Pipes' Routine* Activities CLEAR MANHOLE AND UNDERGROUND PIPES¯ remove manhole cover or grating, ¯ before entering manhole, ensure it is free from noxious gases, ¯ remove all debris, sand and silt from manhole using handtools and buckets, ¯ if water still cannot flow, rod from the manhole downstream of the blockage until the blockage has been removed and water flows again, ¯ if rodding from the downstream manhole is not successful or not possible, pump water from the water-filled manhole and attempt to clear the blockage from this manhole using rodding equipment. *See List of Terms, Volume I . I – 277 PART D - DRAINAGE ManhoIes* and Drainage pipes* REPLACE MANHOLE COVER OR GRATING¯ when a manhole* cover or grating is damaged or broken, remove it completely, including parts which may have fallen into the manhole, ¯ when a cover or grating is missing, search the vicinity. If it is found undamaged, replace it on the manhole. Be sure that the cover or grating is seated properly and level around the complete rim. This will prevent unwanted movement and breakage, ¯ if a new cover or grating has to be provided, ensure that the correct size is used, ¯ if a cover or grating cannot be immediately replaced, make a temporary cover repair using wooden planks of adequate thickness. *See List of Terms, Volume I. I – 279 PART D - DRAINAGE ManhoIes* and Drainage Pjpes* CLEAR MANHOLE AREA¯ locate manhole* using the drainage plan, or by trial excavations, ¯ remove all vegetation within a distance of 2 to 3 metres from the manhole and remove from the site, ¯ excavate all deposits of silt or soil covering the manhole down to a depth of at least 10 cm below manhole cover level and for a distance of at least 1 metre from the manhole edges, ¯ check that the manhole is free of sand or silt and replace the cover. CLEAN CATCH PIT SUMP Follow the same procedure as for CLEAR MANHOLE AND UNDERGROUND PIPES (described on Page I - 277). Remove all silt and debris from the catchpit sump. Periodic* Activities RELAY DRAINAGE PIPE Reconstruct pipe to correct levels and grade, and to construction specifications. *See List of Terms, Volume I. I – 281 PART D - DRAINAGE METHOD A: MOBILE GANG 4.4 COMPLETION AND REMOVAL OF T~MPORARY SIGNS ■ Load tools, equipment and unused materials back onto the truck or trailer. ■ Where they have been used remove the signs, cones and barriers and load them onto the truck or trailer in the following order: 1 "End of Restriction" signs, 2 Traffic cones, 3 "Speed Limit" signs, 4 Barriers, 5 "Road Narrows" signs, 6 "Men Working" signs. I – 283 PART D - DRAINAGE ■ Ensure that the site is left clean and tidy with no stockpiles of material left behind. ■ Move onto the next job. ■ Inspect traffic signs and clean if necessary. I – 285 TYPICAL WORK REPORT ROADSIDE AREAS Work Report No: Date: District: Gang Zone Road No Section: from km to km Location(s): WORK ACHIEVED: MANPOWER USED: Name Grade Hours worked Name Grade Hours worked Name Grade Hours worked EQUIPMENT USED: DIESEL USED: Hrs litres Hrs litres MATERIALS USED: COMMENTS: Foreman: PART D - DRAINAGE 4.5 WORK REPORT The report must be filled in each day, detailing: ■ the work carried out, ■ the resources used. I –287 PART D - DRAINAGE METHOD B: LABOUR BASED In some road maintenance Systems an individual attendant or Iengthman lives close to a road and is responsible for the ROUTINE MAINTENANCE activities on that road. The following activities are suitable for this method: Ditches and Drains CLEARING AND CLEANING RESHAPE/REGRADE/DEEPEN EROSION CONTROL PROVIDE NEW MITRE (TURNOUT) DRAIN Culvert CLEARING AND CLEANING EROSION REPAIR Drifts and Causeways GRADING/CLEARING Manholes and Drainage Pipes CLEAR MANHOLE AND UNDERGROUND PIPES CLEAR MANHOLE AREA CLEAN CATCH PIT SUMP I –289 PART D - DRAINAGE METHOD B: LABOUR BASED5. RESOURCES 5.1 PERSONNEL ■ Supervisor ¯ 1 foreman or overseer visiting regularly. ■ Workforce ¯ attendant or Iengthman. I –291 PART D - DRAINAGE METHOD B: LABOUR BASED 5.2 PLANT AND TOOLS 1 ¯ 1 broom, ¯ 1 pickaxe, ¯ 1 shovel, ¯ 1 hoe or mattock, ¯ 1 rake, ¯ 1 hand rammer with metal shoe, ¯ 1 wheelbarrow, ¯ 1 bucket or watering can, ¯ 1 grass slasher, sickle or scythe, ¯ 1 bush knife or bush hook, ¯ 1 axe, ¯ 1 bowsaw, ¯ 1 file for sharpening tools, ¯ 1 long handled shovel/spike for culvert cleaning, ¯ 1 ditch template and spirit level. 1 Depending on activities to be carried out. I – 293 PART D - DAINAGE 5.3 MATERIALSThe activities suitable for attendant or lengthman do not require imported materials. For simple ditch checks (timber and stones), materials can usually be obtained in the area of the work. 5.4 SIGNS AND SAFETY EQUIPMENT No special arrangements are required for Traffic Signs or Clothing. I – 295 PART D - DRAINAGE METHOD B: LABOUR BASED6. MAINTENANCE METHOD 6.1 PRELIMINARY TASKS ■ The handtools are assigned to the attendant who keeps them at his home for use as necessary. ■ The worksheet will indicate the location and extent of the work to be carried out and the time required for the job. I – 297 PART D - DRAINAGE METHOD B: LABOUR BASED 6.2 EXECUTION OF THE WORK ■ The attendant should use the wheelbarrow to carry the tools and safety items to the site, and collect any materials locally. ■ The work report must be filled in for each day's work. I – 299 Notes and Sketches I – 301 User of this Handbook: NAME: ADDRESS: DATE: I -302 GENERAL INDEX GENERAL INDEX Page Page Aggregate Loss III -21 Camber II - 41 Aggregate Loss III - 99 Camber II - 245 Aggregates III - 33 Camber II - 253 Aggregates Ill-ill Camber 11-293 Aggregates III -207 Camber Formation II - 109 Angle, Slope I - 133 Cascade I - 247 Apron I -193 Catchpit 1-247 Apron I - 257 Catchpit I - 281 Apron IV -69 Causeway I - 195 Attendant I -149 Causeway I-271 Channel I-121 Barriers IV- 13 Chippings Application III -183 Base Patching III - 71 Clean Culvert I - 249 Bearings IV - 9 Cleaning I - 289 Bearings IV- 41 Cleaning IV- 111 Bend II - 43 Cleaning/Clearing IV - 41 Berm I -119 ClearDrainage I -221 Binder III - 35 Clearing I - 289 Binder III -117 Compaction II -39 Binder III -207 Compaction II - 109 Binder Application III - 181 Compaction III -241 Binder Content III - 211 Compaction II - 255 Bitumen III - 35 Compaction II - 307 Bitumen Application III - 175 Concrete Lining I -263 Bitumen Emulsion III -177 Connectors IV -11 Bitumen Temperature III - 143 Connectors IV -45 Bitumen Paint I -261 Corrugations 11-9 Bituminous Concrete III - 197 Corrugations II -71 Bituminous Binders III - 117 Crack Sealing Ill-5 Bituminous Macadam III - 197 Crack Sealing III - 57 Bituminous Mortar III - 197 Cracks I - 189 Blade Position II -49 Cracks III - 11 Bleeding III - 9 Cracks III - 93 Bleeding III -91 Cribwork I - 139 Bolts IV - 45 Crossfall II - 35 Borrow Pit II -243 Crown II -35 Bridge Deck II - 47 Culverts I - 249 Bridges IV - 1 Culverts II -47 Burning I - 107 Culvert Cracking I - 255 I - 303 GENERAL INDEX GENERAL INDEX CONTINUED Page Page Culvert Defects I - 187 Drift I - 195 Culvert Invert I - 261 Drift I - 271 Culvert, Reconstruct I - 265 Curve II - 43 Edge Damage III -19 Cut-off ditch I - 11 Edge Subsidence III - 17 Emulsion III - 185 Daily Planning II -289 Emulsion III - 187 Damaged Signs IV -91 Erosion I - 181 Debris I -187 Erosion I -231 Debris I - 197 Erosion I - 289 Debris IV -9 Erosion IV - 17 Debris IV -41 Erosion Control I - 149 Deck IV - 41 Erosion Control I - 245 Deepen Drain I - 223 Erosion Gullies II - 9 Deepen Drain I - 289 Erosion Gullies II - 71 Defective Masonry IV - 11 Erosion Gullies II - 157 Defective Paint IV - 89 Erosion Gullies II -217 Deformation Ill - 103 Erosion Gullies II -269 Depressions III - 5 Erosion, Outfall I - 185 Depressions III - 15 Erosion, Outlet I - 193 Depressions III - 63 Erosion Repair I - 251 Distance Marker IV -97 Erosion, Slopes I -63 Distance Marker IV - 129 Erosion, Slopes I - 117 Ditch, Grade II -55 Excavation II - 105 Ditches I - 177 Diversion II - 233 Fines III - 207 Diversion II - 241 Fixings IV - 11 Double Dressing III - 87 Fixings IV - 45 Dragging II - 115 Flood Debris IV - 9 Dragging, Graders II - 141 Flow Spreader I -247 Dragging, Tractors II - 135 Fog Spray III - 185 Drags II -125 Fretting III - 99 Drain I-223 Drainage I -163 Gabions I - 139 Drainage Cleaning I - 221 Gabions IV - 73 Drainage Defects I - 177 General Repairs III - 1 Drainage Pipe I - 199 Glazing III -97 Drainage Pipes I -277 Grade Ditch II - 55 Drains I -177 Graded Seal III - 87 I – 304 GENERAL INDEX GENERAL INDEX CONTINUED Page Page Grading I - 273 Lining Repair I - 235 Grading Il -1 Loading II -301 Grading Light II -31 Local Sealing Ill-S Grading Heavy II -32 Local Sealing III -53 Gravel Excavation II - 297 Longitudinal Joint Ill - 249 Gravel Loss II -217 Loss of Shape II -7 Gravel Loss II - 269 Loss of Shape II - 71 Gravel Material II -227 Loss of Shape II -217 Gravel Patching II - 205 Loss of Shape II - 269 Gravel, Patching II - 167 Gravel, Patching II - 183 Major Defects IV-15 Gravel Stockpiles II - 205 Management I - 33 Guard Rail IV -93 Manhole I -199 Guard Rail IV - 121 Manhole I -201 Guide Posts I -275 Manhole I -277 Manhole I -289 Hauling II - 303 Manpower I - 37 Headwall I - 193 Marker Posts I - 275 Headwall I -257 Mitre Drain I -243 Herbicides I - 107 Mix Temperature III -241 Mixtures III -35 Jointing III -249 Joints IV - 41 Nails IV - 45 Joints IV -45 Non Structural Defects IV -9 Kerb I - 121 Obstructions I -53 Kilometre Stone IV – 97 Obstructions I - 93 Kilometre Stone IV - 129 Obstructions I - 149 Obstructions I - 177 Labour Based Drainage....I -289 Off Loading II -305 Labour Based Patching II - 199 Organisation I -38 Labour Based Reshaping .II - 65 Outfall Basin I - 269 Labour Based Surfacing III - 169 Outfall Erosion I -185 Labour Based Work I - 149 Outlet Erosion I - 193 Landslip I -65 Overlay III -191 Layby I -45 Lengthmen I – 14 9Paint IV - 11 Line Drain I – 245 Painting IV - 53 Lining Damaged I - 183 Patching II - 153 I – 305 GENERAL INDEX GENERAL INDEX CONTINUED Page Page Patching Ill-5 Repainting IV- 113 Patching III - 67 Reshape Drain I - 223 Patching III - 71 Reshape Drain I - 289 Pavement Markings IV -95 Retaining Wall I - 141 Pavement Markings IV - 123 Retaining Wall IV - 65 Paver III -235 Rivets IV - 47 Pitching I - 129 Road Markings IV - 95 Planking IV -41 Road Markings IV - 123 Planks IV - 49 Road Side Areas I - 41 Planning II -270 RoIling III - 155 PlantMix III -197 Rust I -191 Plant Mix III -209 Ruts II - 7 Pointing Masonry IV - 57 Ruts II - 71 Ponding I -179 Ruts II -157 Posts, Guide/Marker I -197 Ruts II -217 Potholes II - 7 Ruts II - 269 Potholes II -71 Ruts III - 15 Potholes II -157 Rutting III -17 Potholes II - 217 Potholes II - 269 Safety I - 35 Potholes III - 23 Safety Barrier IV - 59 Premix III - 69 Safety Barrier IV - 93 Preparation II -293 Safety Barriers IV - 121 Productivity II - 286 Safety Defects IV - 13 Safety Measures IV - 33 Quarry II -243 Sand III - 207 Quarry Preparation II -295 Sanding III -5 Sanding Ill-Si Random Stone IV -61 Sandwich Seal III -87 Rate of Spread Ill - 145 Scour IV -69 Rebuild Drain I - 281 Scour Protection I - 237 Reconstruct Culvert I - 265 Scuppers IV - 9 Regrade I -289 Scuppers IV-41 Regrade Drain I -223 Seal III -67 Regrade Drain I - 233 Sealing, Cracks III - 57 Regravelling (Labour and Sealing, Local III - 53 Tractors) II -263 Seeding I - 125 Regravelling(Mechanised) .II – 213 Setting Out II -97 Regulatory Signs IV - 143 Setting Out Ill - 179 I – 306 GENERAL INDEX GENERAL INDEX CONTINUED Page Page Settlement I - 189 Stabilisation I - 131 Shoulder I - 47 Stockpile I - 155 Shoulder I -149 Stockpiling Gravel II -297 Shoulder Depressions I - 57 Stockpiling Gravel II - 309 Shoulder Gravel I - 149 Stone III - 207 Shoulder Material I - 109 Stone Pitching I - 129 Shoulder, Reshape I - 95 Storage of Signs IV - 139 Shoulder Ruts I - 57 Streaking III - 101 Shoulder Vegetation I - 59 Stripping III - 99 Shoulder, Vegetation I - 101 Structural Defects IV - 11 Shoving III -25 Subsidence III - 17 Sign Replacement IV - 127 Superelevation II -43 Sign Size IV-145 Support II -225 Signs, Regulatory IV - 143 Support II -277 Signs Store IV - 139 Surcharging I - 137 Signs, Temporary IV - 145 Surface Dressing III -83 Silted/Blocked Ditches II -9 Surface Dressing Ill - 165 Silted/Blocked Ditches II -71 Surface Dressing III -169 Silting I - 177 Silting I -187 Tack Coat III -65 Single Seal III -87 Tack Coat III -213 Slip I - 131 Tack Coat III - 233 Slip I - 135 Temperature III - 143 Slope Angle I - 133 Temperature III - 241 Slopes I -49 Temporary Signs IV - 145 Slopes I - 61 Termites IV - 43 Slopes Erosion I - 63 Traffic Signs IV - 81 Slopes Erosion I - 117 Transverse Joint III -251 Slopes, Slip I -65 Turfing I - 123 Slopes, Vegetation I - 61 Turnouts II - 59 Slopes, Vegetation I - 115 Slurry III - 57 Untreated Wood IV - 11 Slurry Seal III -187 Sodding I -123 Vegetation I -149 Soft Spots II -157 Vegetation IV-91 Spot Regravelling II -215 Vegetation Control IV - 119 Spot Regravelling II -267 Vegetation, Shoulder I -59 Spray Bar III - 145 Vegetation, Slopes I -61 Spreading II - 305 Vegetation, Slopes I - 115 I – 307 GENERAL INDEX GENERAL INDEX CONTINUED Page Warning Signs IV - 13 Wattling I -127 Weepholes IV-9 Windblown Debris IV - 9 Windrow II - 51 Windrow II - 143 Wood Preservation IV - 55 Workshop Repair IV - 119 I - 308 ACKNOWLEDGEMENTS The contents of this handbook draw on many sources, past and present, and it would be impossible to acknowledge them all individually. Much of the material is an updating of the UN/ECA Maintenance Handbook for Africa, compiled by experts from France, Germany and the United Kingdom, and published in 1982. Its three volumes encapsulated the broad experience of highway engineers, maintenance managers, consultants and researchers from many different countries. The present revision was undertaken by Mr R.C. Petts of Intech Associates, in close association with the Overseas Centre of the Transport Research Laboratory. The work was funded by the UK Overseas Development Administration and supported and guided by a subcommittee drawn from the PIARC Committee on Technology Transfer and Development (C3). It benefited from the collective wisdom of that committee and the countries represented within it. These included Australia, Algeria, Belgium, Brazil, Burkino Faso, France, Germany, India, Italy, Morocco, Poland, Portugal, Senegal, Spain, Turkey, the United States of America, the United Kingdom and the World Bank. On behalf of the subcommittee I would like to record our sincere thanks to all those who contributed, in whatever way, to the production of this second version of the Maintenance Handbook and to making it more valuable to a wider international audience. I am sure it will fulfil its intended purpose of strengthening the capabilities of maintenance workforces and giving them a stronger sense of professional pride in the vital work they are doing. I – 309 ACKNOWLEDGEMENTS continued Any revision of this kind is an ongoing process, and comments or suggestions for further improvements should be made known to the PIARC Central Office at 27 rue Guenegaud 75006 PARIS, France. Fax +33(1) 46 3384 60J Stuart Yerrell Chairman, Subcommittee C3-6d WHAT IS PIARC? Founded in 1909 following the 1 st Internationla Road Congress held in Paris in 1908, the Permanent International Association of Road Congresses (PIARC) is the oldest of the international associations concerned with roads and road engineering. The general aim of the Association is to improve international co-operation and to foster progress in: • the formulation of road transport policies • the planning, construction, improvement and maintenance of roads • the operation and management of road systems within the context of wider policies towards transport. To achieve these aims PIARC: • organises a World Road Congress every four years and various technically oriented events • creates and co-ordinates Committees • publishes a number of documents including a periodic bulletin It is assisted in its task by National Committees. PIARC is a non political and non-profit association It was granted consultative status, category II, to the Economic and Social Council of the United Nations in 1970. The official languages of PIAC are French and English There are several catagories of members: Governments, regional authorities, public bodies, collective members and Individual members As of 1 January 1994, PIARC has 72 member Governments and 2100 members in 100 countries. PIARC has strong links with several regional organisations and is in favour of networking between countries dealing with similar questions. PIARC may help to create and/or develop such networks. I -311 PIARC Committees and Working Groups are composed of engineers and experts appointed by member countries. They act on a continuous basis between each Congress and participate in international meetings dealing with subjects within their competence On average they hold two plenary meetings a year. As of 1 January 1994, Committees and Working Groups gather approximately 700 engineers and experts from 40 countries. Thirteen Committees and four Working Groups are active (period 1991 - 1995) • COMMITTEESC 1 Technical Committee on Surface Characteristics C 3 Committee on Technological Exchanges and Development C 4 Committee on interurban Roads C 5 Committee on Road Tunnels C 6 Committee on Road Management C 7 Technical Committee on Concrete Roads C 8 Technical Committee on Flexible Roads C 9 Economic and Finance Committee C 10 Comm 11cc on Urban Areas C 11 Committee on Road Bridges C 12 Technical Committee on Earthworks Drainage, Subgrade C 13 Committee on Road Safety C 14 Committee on the Environment • WORKING GROUPS G 1 PIARC Winter Road Congress G 2 Natural Disaster Reduction G 3 Modern Traffic Control and Management G 4 Heavy Freight Vehicle issues • PIARC PUBLICATIONS - Committees and Working Groups publish synthetic documents recommendations and state of the art. These documents intended for decision makers, design and field engineers and researchers, are based on wide international consensus I – 312 •CONGRESS DOCUMENTS - The documents published on the occasion of World Road Congresses are an invaluable source of information and experts agree on the fact that they are most interesting and unique. • PERIODICAL BULLETIN “Routes/Roads” - The Association Bulletin was issued for the first time in 1911. It features comprehensive files on road matters in various countries, articles written by members of Committees and Working Groups and news of interest to the world road community. Its issues of a hundred pages are published three to four times a year. • TECHNICAL DICTIONARY OF ROAD TERMS AND LEXICON - The first edition of the DICTIONARY was issued in 1931. The sixth edition (French/English) was published in 1990. The Dictionary is published with the financial support of UNESCO and is translated into eighteen languages: Arabic, Chinese, Croatian, Czech, Danish, Dutch, German, Greek, Hungarian, Italian, Japanese, Lithuanian, Polish, Portuguese, Romanian, Russian, Spanish and Slovak. The Lexicon contains over 12,000 expressions in English and French and is also available on computer disk. All these documents are published in French and English. PIARC publications catalogue is free of charge and can be orderedthrough: ANRTP 32, rue du Marché commun Centre de Gros - Case postale 1220 44082 NANTES Cédex 03 (FRANCE) I - 313 WHERE TO ORDER THE HANDBOOK The English version of Volume I: Maintenance of Roadside Areas and Drainage Volume II: Maintenance of Unpaved Roads Volume Ill: Maintenance of Paved Roads Volume IV: Maintenance of Structures and Traffic Control Devices may be ordered from: Transport Research Laboratory Crowthorne, Berkshire RG1 1 6AU United Kingdom The Road Maintenance Handbook is also being published in French, Spanish and Portuguese. Other languages are under consideration. For more details, please contact PIARC Central Office - 27 Rue Guenégaud, 75006, PARIS, France. Fax: +33 (1) 46 33 84 60. Printed by:- Borough Press (Wiltshire) Ltd, SN2 6YW, UK I - 314