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A system of bridge inspection and data management in developing countries. 6th Conference of REAAA, Kuala Lumpur, 4-10 March 1990

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Department For International D FID ~~~~Development TITLE: by: A system of bridge inspection and data management in developing countries J Parry Overseas Centre Transport Research Laboratory Crowthorne Berkshire RG45 6AU United Kingdom PAI 222190 Parry, J D, 1990. A system of bridge inspection and data management in developing countries. In: REAAA. Proceedings of the 6th Conference of REAAA. Kuala Lumpur 4 -10 march 1990. A SYSTEM OF BRIDGE INSPECTION AND DATA MANAGEMENT IN DEVELOPING COUNTRIES BY j D PARRY, Overseas Unit, TRRL ABSTRACT This paper describes a system of bridge inspection designed to assist a District Engineer, who may not be a~bridge specialist but-nevertheless has a number of structures in his charge. This situation has been shown to exist in developing and industrialised countries. Overseas Road Note 7, Volumes 1 and 2 (1988) describe the system and give guidance on the management of bridge inspection procedures, reports and other bridge data in the forms of the bridge inventory and drawings. The main features of this publication are: i. A manual for the engineer in charge, ii. An instruction and reference book for technician inspectors and i~ii. A comprehensive check-list to be used as the inspection report form. The system was given field trials in several countries before publication, the most extensive being in Malaysia with the Co-operation of Jabatan Kerja Raya. INTRODUCTION 1 In most countries it is now well recognised by those involved with highways that timely, appropriate maintenance is cost effective, from the point of view of the maintenance organisation as well as that o-f the road user and the national economy. It is also clear that the maintenance problem is larger now than ever before, because of the large increase in the size of national networks over recent decades and because of deterioration due to age and wear. Good maintenance management is the aim of all highway departments but highway maintenance is universally under-financed and under-staffed. 2 In order to meet the demand for efficient use of maintenance resources, highway departments are now employing maintenance management systems of varying complexity, all claiming to improve the efficiency of the maintenance process, and all based on detailed inspection of the road network. However, these systems tend to concentrate on the road carriageway and give little or no attention to the structures, which form a small but none-the-less essential part of the network. 3 When road structures deteriorate, extensive sections of the road network may be affected by weight, height or width restrictions on vehicles, and road closure in cases of bridge failure. The result is a large and often preventable expense to the road users and the highway department. The problem is extensive in both developing and industrialised countries. 4 ~~It its fifth annual report to the US Congress, the Federal Highway Administration (1984) rated about 45 percent of the existing bridges in 'the Unfited States as either functionally or structurally deficient. 5 It is a false economy to assume that bridges are in good condition until faults become apparent to the road user, because by then the damage may be extensive and difficult to repair. One of the main purposes of a regular bridge inspection system is to detect faults when they are still minor and relatively cheap to rectify. 6 ~~This paper describes a system of bridge inspection and management of bridge data, which can be incorporated into a road maintenance management system, or operated by a highway department independently of any such system. 7 The efficient maintenance of roads and bridges alike is dependent on frequent inspections of the stock, and then interpretation of inspection data, followed by appropriate remedial treatment. In industrialised as well as developing countries there are rarely enough engineers to perform the first stage, i.e. bridge inspection. In practice the bridge engineers at highway department headquarters show little interest in maintenance and are too few to take on the task of regular inspection nationwide. The engineers responsible for highway~ in the separate districts are rarely experienced in bridges and either reluctant, or too busy, to inspect personally all the bridges in their charge. 8 There is, therefore, in many countries, a requirement that bridges should be inspected more frequently than at present. TRRL OVERSEAS ROAD NOTE 7 (1988) 9 This is a further publication in the series of practical guides published by the Overseas Unit at the Transport and Road Research Laboratory in the UK, primarily for developing countries. It is entitled, "A Guide to Bridge Inspection and Data Systems for District Engineers." In this subject as in many others, there is no simple division between industrialised and developing countries, and although this guide was written primarily for the latter, it has been well received in the United States as well as in countries of varying development in Asia and Africa. 10 There are two fundamental problems addressed by ORN 7. The first is the organisation and use of the various bridge records and the second is the management of bridge inspection. This corresponds with the basic requirements for the maintenance management of any commodity, i.e. (1) a complete record of the stock and (2) regular bulletins of current condition. Bridge Records 11 ~These are divided into four categores i. The bridge inventory. ui. Drawings and calculations. iii. Inspection reports. iv. Maintenance records. 12 The guide recommends that the Bridge Inventory should take the form of one A3 size card for each bridge. A sample layout is shown in Figures 1 and 2. 13 As well as showing all the, basic information about each bridge or culvert, the cards contain information used in the inspection process. 14 Two sides of an A3 size card provide sufficient space for photographs, location sketch, plan, elevation, and cross-section 'of the structure, construction drawing and calculation references and notes, as well as use restrictions which may be in force. It is recognised that such detailed information may not be available in all cases but the engineer is encouraged to obtain as much data as possible to enable him to assess the importance of faults subsequently recorded. 15 The guide contains a detailed description of each item of data on the bridge record card with recommendations for a bridge numbering system, based on route number and distance to the bridge from the road origin. Advice is given on methods which may be used to establish a new inventory. 1 6 It is rare that a full set of Drawings and Calculations is available for bridges more than a few 'years old. The types of drawings and calculations commonly found are described as: i. Standard - drawings that may be suitable for a number of sites, without specific site details. ii. Original design drawings not marked "as built."- These will not include changes made during construction. iii. As-built drawings. These will not record modifications made since construction, such as widening,, strengthening, etc. iv. As-built with all modifications shown and dated, with any calculations made in connection with the passage of unusual loads. 17 It is important that Inspection Reports should be clearly understood by all who refer to them. ORN 7 includes a standard format for an inspection form that covers all common types of bridge design and commonly used materials. It is simple to complete and to read, and allows for more detailed reporting in the form of further notes or sketches. 1 8 One advantage of using a standard format is that consecutive reports may be easily compared to detect small, progressive deterioration which can z 4, k Ii. A 7' '1, ill1 V-' I- ' 4 P