Au stra li an Br idge Inspe cti on Pro ce sses

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1 Number of structures Au stra li an Br idge Inspe cti on Pro ce sses by Andrew Sonnenberg, Bridge Engineering Manager, pitt&sherry Paper presented at the 2014 Small Bridges Conference pitt&sherry has undertaken thousands of bridge inspections across Australia, from as far north as Cairns to as far south as Hobart. The purpose of this paper is to make councils and other asset owners aware of the differences in inspection procedures from state to state, and suggest improvements that could be made to those procedures. 1 A u s t r a l i a n b r i d g e s In Australia most bridges are managed by councils, state road authorities and rail operators. The largest bridge/culvert asset owner in Australia is the Australian Rail Track Corporation (ARTC), which manages over 20,000 structures etending from to Perth. Eight regional road authorities manage bridge and culvert structures. Ranked by number of bridges and culverts managed, the three largest are VicRoads, the Department of Transport and Main Roads (DTMR) and NSW Roads and Maritime Services (RMS). A breakdown of the number of structures controlled by each authority is shown in the graph below TMR VicRoads Within the boundaries of each regional road authority there are many councils and other state asset owners that control a greater number of structures for eample, approimately 8,000 structures are managed by n councils alone. 2 O b j e c ti v e o f b r i d g e i n s p e c ti o n s Bridge inspections are a necessary and important part of effective bridge asset management. They provide the base information from which decisions can be made about current and future ependiture requirements and the levels of service on a network. Distribution of bridge and culvert structures owned by regional road authorities RMS DTEI TMR Asset owner MRWA (WA) ACT DPI Perhaps the most important objective of bridge inspection is the management of risk. Once structural defects have been identified, their repair can be programmed based on available funds and the perceived risks across the network and across asset classes. The inspection process provides a review and audit process that helps asset owners: build a correct and up-to-date inventory of their structures plan proactively for preventive maintenance and asset repair and replacement, as well as identify works requirements. Inspections may also be used to audit past inspections. In this way the asset owner can see whether defects have been addressed or not, and if they have deteriorated. 3 B r i d g e i n s p e c ti o n p r o c e s s e s Each state road authority s inspection manuals essentially have the same objective to manage the risk associated with the assets. However, the etent and type of information to be collected differs. In this paper we review and compare inspection manuals from the three largest state road asset owners: VicRoads, DTMR and RMS. 1

2 The three road authority manuals we discuss have all evolved from the Pontis system developed by American state road authorities. VicRoads Road Structures Inspection Manual (April 2011) This is the only inspection manual that covers all significant roadside structures, from noise walls and lighting poles to comple bridges. It also contains relevant information with regard to policy, procedures and condition ratings associated with all types of routine inspections. DTMR Bridge Inspection Manual (June 2004) The DTMR manual covers all bridge assets and large culverts and contains information relating to policy, deterioration mechanisms and inspection procedures for all types of routine inspections. RMS RTA Bridge Inspection Procedure Manual (June 2007) This manual contains information relating only to inspection procedure and condition rating for bridges and large culverts. For information relating to policy, RMS makes reference to its RTA Bridge Inventory, Inspection and Condition Rating Policy (2011). 4 C o m p a r i s o n o f m a n u a l s The manuals differ in terms of content, application and approach. The differences considered most relevant to this discussion are: the structures covered inspection levels frequency of inspection scope of inspection data collection requirements condition state definitions and recommended repair treatments. Structures covered Each state authority is responsible for bridge, culvert and roadside infrastructure associated with the roads under its control. Traditionally the requirements for inspection and maintenance for assets not associated with crossing or road support were not as well understood as they are for bridge and culvert structures. VicRoads, which has the most recent inspection manual, has added all significant assets to the scope of the manual, including sign structures, retaining walls, weighbridges and lighting masts. In and the scope of the bridge inspection manuals is limited to bridges and culverts of certain sizes. The manual does not cover other structures, but the Bridge Inventory System (BIS) does allow for individual asset owners to add other structures to their database. Unlike the VicRoads system this option does not provide standard component numbers or condition rating information for these structures. While the manuals are relevant to most bridge structures, there are some unique and more comple long-span and moveable bridges that are not covered. The RMS inspection manual makes allowance for comple structures to have an individual inspection procedure. Tabl e 1 Inspection level Level 1 Level 2 Level 3 Inspection level s State Inspection type Comple structures are defined as those that may, due to their size, material, design or importance, require more targeted inspections. Inspection levels The n and inspection manuals contain three levels of inspection, while in there are four. In general, the levels of inspection are divided into Routine Inspection, Condition Assessment and Detailed Engineering Inspections. The inspection level and inspection type for each state is shown in Table 1. Frequency of inspections The frequency of inspections used by each manual is shown in Table 2 and is relatively consistent across the manuals although the manual has the most scope to etend the frequency of level 2 inspections depending on the location of components to be inspected and the condition of the structure. Visual inspection for routine maintenance issues and possible further inspection. Visual inspection to assess the condition rating of the structure and its components. Detailed engineering inspection to target specific issues and assess load-carrying capacity of a structure or group of structures. Detailed engineering inspection to identify and quantify deterioration and provide a load rating if required. Structural safety inspection of full structure or specific elements to identify and quantify structural issues. Level 4 Load capacity assessment to determine the load capacity of the bridge. 2

3 Ta bl e 2 Fre que ncy o f inspe c tions Scope of inspections Inspection level State Frequency Level 1 6 months maimum 6 12 months According to road maintenance 2 years (1 5 years)* 2 years (1 8 years)* 2 years (1 4 years)* When required When required When required Level 2 Levels 3 & 4 (NSW only) * The absolute maimum duration between level 2 inspections of structures. This is dependent on structure type, condition and location. Ta bl e 3 S cope of le v e l 2 inspe c tion Task Vic. Qld NSW Condition rating of components Condition rating of whole structure Identify structural defects Identify structures/components for further inspection Identify structure/components Identify supplementary testing Obtain photographic record * Sounding of timber members using hammer Timber drilling to test deterioration Soundings to measure waterway profile Underwater inspection * * Recommend maintenance/repairs Recommend timeframe for maintenance/repairs This item is part of the scope of every level 2 inspection The scope of inspections varies from state to state. This appears to be influenced by local factors such as predominant structure type and waterway type. For all states, the scope for a level 1 inspection is so similar that it does not warrant discussion here ecept for the level 1 inspection prescribed by the New South Wales manual, which is limited to signs of obvious accidental damage, deformations or safety issues rather than routine maintenance concerns. In and the inspections are used to identify required maintenance activities and identify any obvious warning signs that would indicate a requirement for further inspection. The scope of works for a level 2 inspection can vary greatly across the authorities. Table 3 outlines some of the tasks that are contained in the scope of a level 2 inspection in each state. The scope of works for a level 3 inspection is similar in all states with the eception of, where a load capacity assessment is always part of the scope of works. In, load assessment may be specified but is not part of the standard scope, while in a level 3 inspection does not include load assessment as this is the entire scope of a level 4 inspection. * This item is part of the scope of some level 2 inspections 3

4 Data collection requirements Each inspection procedure has reasonable differences from state to state. A significant factor in this is the scope of works and the asset databases used by the different authorities that write the procedures. For level 1 inspections, the data that is collected is much the same in and, while in only significant issues need be recorded. In and the inspector is required to record information on maintenance issues and any obvious signs of distress, damage or deterioration of the structure or any of its elements. Inspectors are required to recommend maintenance works and further inspection if required. Inspectors are also required to verify the generic asset data contained in the asset database. For level 2 inspections, the data collection is similar in and while in the data collected is much more specific to each part of the structure. In all of, and, generic asset data and component data are verified, and component condition ratings and structure condition ratings are provided. There are some differences in the manner in which condition data is collected and recorded as well as some differences in the way generic data is recorded. These are recording GPS data for structures, taking a photographic record and recommending actions for defects. In and the inspector is required to record the GPS coordinates of the structure. This is not required in. In each state the requirements for photographic records are different. In an inspector is required to photograph all condition state 3 or 4 defects while in only condition state 4 defects require a photograph. In there is no requirement for obtaining a photographic record of the defects. For level 3 or 4 inspections the data recorded is based on the scope of the inspection and the discretion of the engineer carrying out the inspection. Data collection methods Each inspection procedure has reasonable differences from state to state. A significant factor in this is the scope of works and the asset databases used by the different authorities that write the procedures. DTMR, RMS and VicRoads provide paperbased inspection forms to be filled out on site at the time of inspection, and entered at a later date into the bridge asset database. Condition ratings Each inspection manual has guidelines for rating the condition of the components of a structure. Surprisingly, these vary significantly. Some eamples of the differences are eplained below. Component codes When rating the condition of steel open girders, the component code used is 2S in, 22S in and SBJI for the same component in New South Wales. Detail used for recording condition In the manual, the condition data is recorded down to a span-by-span condition for components, while in the components are recorded for the bridge as a whole, making the n system much less tedious to implement. When a defect is observed, however, all states require a specific description of the defect s location. Units of measurement for recording condition In the and manuals the condition of a component is measurement by the physical quantity, such as metres, whereas for the n roads system the measurement of quantity is as a percentage of the total. Recommended maintenance and repairs Each bridge inspection manual requires that inspectors recommend actions, treatments or maintenance for defects observed during inspections. Again there is no general consensus on the approach that should be taken. In and the inspector is provided with a list of the possible maintenance and repair actions to recommend. These actions range from generic actions such as concrete patching to specific actions such as providing temporary abutment support or concrete sleeving of timber piles. The provision of such a list of recommendations provides consistency in recommendations from different inspectors with different eperience, and allows asset owners to plan works more effectively. In the inspector is required to recommend the action that seems most appropriate to them. This can lead to vague or very specific repair items that may not be favoured by the asset owner and could be difficult to plan for effectively. None of the manuals stipulates any requirement to record the cost of recommended maintenance or repairs, which is essential for developing a program of works and getting an initial understanding of the magnitude of defects, particularly for Councils who may not have the technical capacity to appreciate the severity of a defect and therefore the associated costs to repair it. All three manuals require the inspector to recommend a completion date for repairs or maintenance. RMS and DTMR leave it to the inspector to determine the urgency of treatments, while VicRoads has a predefined system to determine the urgency of a treatment. 4

5 5 I m p r o v e m e n t s t o b r i d g e i n s p e c ti o n p r o c e s s e s Each asset owner has a similar objective in mind when conducting bridge inspections, yet a review of the bridge inspection manuals of the three regional road asset owners that control the greatest number of bridges and culverts indicates differences in a number of areas. By reviewing these differences we have questioned which manual has the best practice, or whether all manuals could be improved. The following areas were identified for improvement: inspection forms guidance notes data collection requirements urgency recommendations condition rating risk scoring soundings inspection frequency review of past inspections. Inspection forms The manuals are tailored to the collection of data using a paper based system and then entering the data into a corporate database. Unfortunately, large state road authorities often lag behind current best practice which is to collect data once at the source. The manual forms are perhaps the most tedious to fill out, with multiple pages of repetitive data. Although much could be done to make these forms easier to use it is suggested that consideration be given to updating the manuals to require electronic data collection and then focusing on the types of reports that are to be generated from the data collected. For eample the road authorities could stipulate a data format for the data they want to collect. Guidance notes The manual contains an incomplete set of guidance notes for eternal parties. It is suggested that consideration be given to providing access to all guidance notes to allow other authorities to benefit from the DTMR valuable eperience. Data collection requirements Photographic requirements Photographs are essential for understanding the nature of a defect and tracking how the defect changes over time. It was observed that only photos for condition 4 defects in are required and the RMS manual is silent on this matter. It is suggested that asset owners adopt the VicRoads approach and ensure photographs are taken of all condition 3 and 4 defects. GPS records GPS records are important for locating structures. While street, line names, and chainages my change, GPS coordinates remain stable and allow the asset owner to readily map the location of the structures and inspectors to readily find the structures. It is suggested that GPS coordinates are collected as part of the inspection process, even though the manual does not currently require this to be done. It is also suggested that rather than collecting just one coordinate at least two coordinates are taken at etremes of the structure so that the orientation of the structure may be determined and later represented in either a 2-D or 3-D form. Cost of repairs It is not currently a requirement of the inspection manuals to record the cost of repairs and maintenance. In many instances, to gain an appreciation of the cost of a repair a site inspection is required. It is suggested that asset owners request that at the time of inspection the inspector estimates the cost of the recommended action and that the authorities systems have the ability to record this cost and then revise it as required. It is also suggested that the asset owner records the cost of past repairs and uses this information to audit and enhance the inspector s estimate. Past records could also be used to provide a set of rates in the inspection manuals for inspectors to use when conducting inspections. Urgency recommendations The urgency of treatment is important in risk management as it relates to the priority given to mitigation measures. In the DTMR and RMS procedures the inspector is given the freedom to select a timeframe for treatments. Depending on the inspector s appetite for risk and personal eperience the timeframe for treatment could vary significantly. With the VicRoads system the timeframe is given but is not specifically linked to the component or defect types. Therefore although it adds some understanding to the required timeframe to provide a treatment, it cannot be relied upon. The process could be improved by adding response times for the treatment of defects for particular components based on condition. Such an approach has been adopted by a number of rail authorities including the ARTC. Condition rating The review has determined that there are differences in the condition rating guidelines between the road authorities. A national bridge inspection manual or guidelines on condition rating could overcome the discrepancies between authorities and reduce the cost of each authority maintaining its own manual. Consideration should be given to an organisation such as the National Transport Commission or an Austroads committee addressing bridge inspection procedures and accreditation at a national level. 5

6 Risk scoring The risk scoring procedures for assessing the over-risk of structures is not well defined by any of the risk scoring methodologies to provide for consistency in the application of federal government funding. Soundings for scour Soundings for scour are standard for the DTMR manual but not for the other manuals. It is recommended that soundings be conducted for structures unless an authority is able to deem that the structures are not susceptible to scour. Inspection frequency It is recommended that consideration be given to modifying the bridge inspection manuals of VicRoads, RMS and DTMR to include for regular level 3 inspections as currently none of the manuals calls for regular loading rating. Load rating of the structures is one of the key methods for understanding the risk of structural failure and the effect of defects in structures on their load carrying capacity. Including load rating on a regular basis would also align these manuals with a number of overseas manuals. Moreover the ARTC uses a process of regular engineering (level 3) inspections. During these inspections the capacity of each key element of a structure to safely carry current design loads and actual loading based on the current condition of structures is determined. Review of past inspections It is not a requirement of the level 2 inspection process to review past inspections and it has been the practice of VicRoads not to supply such information to their inspectors. pitt&sherry often conducts inspections for asset owners and uses past data collected or the data supplied by council during the inspection to audit whether defects have been repaired, stayed the same or deteriorated. Although it takes longer to conduct an inspection when auditing past data it provides an opportunity to correct previous mistakes and avoids inconsistencies in current inspections. The review also assists in understanding the urgency of repairs. 6 C o n c l u s i o n By reviewing the inspection manuals of the three largest road bridge asset owners a number of differences between the manuals were observed, with some manuals adopting better practices than others. Each manual could be improved by adopting the best practice between the manuals as well as by reviewing and adopting the best practice of the rail asset owners and overseas authorities. Give the effort required to maintain and update inspection manuals it is considered that there would be benefit in developing a national bridge inspection manual and accreditation process that not only addresses the needs of the largest road bridge asset owners but other asset owners, such as councils and rail authorities. Improved and consistent practices across Australia s bridge infrastructure would lead to efficiencies with respect to risk management and service levels across the country. R e f e r e n c e s Austroads 2012, Investigating the development of a bridge assessment tool for determining access for high productivity freight vehicles, research report, February Department of Transport and Main Roads 2004, Bridge inspection manual, June Roads and Maritime Services 2007, Bridge inspection procedure manual, June VicRoads 2011, Road structures inspection manual, April