Alternate structural system of incorporating flat bed rail wagons as low volume road bridge decks

The stimulus for this project rose from the need to find an alternative solution to aging superstructures of road-bridge in low volume roads (LVR). The solution investigated, designed and consequently plans to construct, involved replacing an aging super-structure of a 10m span bridge with Flat-Bed Rail Wagon (FBRW). The main focus of this paper is to present alternate structural system for the design of the FBRW as road bridge deck conforming to AS5100. The structural adequacy of the primary members of the FBRW was first validated using full scale experimental investigation to AS5100 serviceability and ultimate limit state loading. The bare FBRW was further developed to include a running surface. Two options were evaluated during the design phase, namely timber and reinforced concrete. First option, which is presented here, involved strengthening of the FBRW using numerous steel sections and overlaying the bridge deck with timber planks. The idea of this approach was to use all the primary and secondary members of the FBRW in load sharing and to provide additional members where weaknesses in the original members arose. The second option, which was the preferred option for construction, involved use of primary members only with an overlaying reinforced concrete slab deck. This option minimised the risk associated with any uncertainty of secondary members to its structural adequacy. The paper will report selected results of the experiment as well as the design phases of option one with conclusions highlighting the viability of option 1 and its limitations.

Effects of opening in the cross girders of the flat bottom rail wagons to the load transferring mechanisms when used as road bridge deck

A Flat Bed Rail Wagon (FBRW) has been proposed as an alternative solution for replacing bridges on low traffic volume roads. The subject matter for this paper is to investigate the impediment to load transfer from cross girders to main girder, through visually identifiable structural flaws. Namely, the effect of having large openings at close proximity to the connection of the main girder to the cross girder of a FBRW was examined. It was clear that openings locally reduce the section modulus of the secondary members; however it was unclear how these reductions would affect the load transfer to the main girder. The results are presented through modeling grillage action for which the loads applied onto the FBRW were distributed through cross girders to the main girder.

Performance load testing and structural adequacy evaluation of road bridge decks

Many ageing road bridges, particularly timber bridges, require urgent improvement due to the demand imposed by the recent version of the Australian bridge loading code, AS 5100. As traffic volume plays a key role in the decision of budget allocations for bridge refurbishment/ replacement, many bridges in low volume traffic network remain in poor condition with axle load and/ or speed restrictions, thus disadvantaging many rural communities. This thesis examines an economical and environmentally sensible option of incorporating disused flat rail wagons (FRW) in the construction of bridges in low volume, high axle load road network. The constructability, economy and structural adequacy of the FRW road bridge is reported in the thesis with particular focus of a demonstration bridge commissioned in regional Queensland. The demonstration bridge comprises of a reinforced concrete slab (RCS) pavement resting on two FRWs with custom designed connection brackets at regular intervals along the span of the bridge. The FRW-RC bridge deck assembly is supported on elastomeric rubber pads resting on the abutment. As this type of bridge replacement technology is new and its structural design is not covered in the design standards, the in-service structural performance of the FRW bridge subjected to the high axle loadings prescribed in AS 5100 is examined through performance load testing. Both the static and the moving load tests are carried out using a fully laden commonly available three-axle tandem truck. The bridge deck is extensively strain gauged and displacement at several key locations is measured using linear variable displacement transducers (LVDTs). A high speed camera is used in the performance test and the digital image data are analysed using proprietary software to capture the locations of the wheel positions on the bridge span accurately. The wheel location is thus synchronised with the displacement and strain time series to infer the structural response of the FRW bridge. Field test data are used to calibrate a grillage model, developed for further analysis of the FRW bridge to various sets of high axle loads stipulated in the bridge design standard. Bridge behaviour predicted by the grillage model has exemplified that the live load stresses of the FRW bridge is significantly lower than the yield strength of steel and the deflections are well below the serviceability limit state set out in AS 5100. Based on the results reported in this thesis, it is concluded that the disused FRWs are competent to resist high axle loading prescribed in AS 5100 and are a viable alternative structural solution of bridge deck in the context of the low volume road networks.

Performance testing of road bridge deck containing flat rail wagons

A road bridge containing disused flatbed rail wagons as the primary deck superstructure was performance tested in a low volume, high axle load traffic road in Queensland, Australia; some key results are presented in this paper. A fully laden truck of total weight 28.88 % of the serviceability design load prescribed in the Australian bridge code was used; its wheel positions were accurately captured using a high speed camera and synchronised with the real‐time deflections and strains measured at the critical members of the flat rail wagons. The strains remained well below the yield and narrated the existence of composite action between the reinforced concrete slab pavement and the wagon deck. A three dimensional grillage model was developed and calibrated using the test data, which established the structural adequacy of the rail wagons and the positive contribution of the reinforced concrete slab pavement to resist high axle traffic loads on a single lane bridge in the low volume roads network.

Alternative structural design strategies for bridge decks in low traffic volume roads

This research is part of a major project with a stimulus that rose from the need to manage a large number of ageing bridges in low traffic volume roads (LTVR) in Australia. The project investigated, designed and consequently constructed, involved replacing an ageing super-structure of a 10m span bridge with a disused Flat-bed Rail Wagon (FRW). This research, therefore, is developed on the premises that the FRW can be adopted as the main structural system for the bridges in LTVR network. The main focus of this research is to present two alternate deck wearing systems (DWS) as part of the design of the FRW as road bridge deck conforming to AS5100 (2004). The bare FRW structural components were first examined for their adequacy (ultimate and serviceability) in resisting the critical loads specified in AS5100(2004). Two options of DWSs were evaluated and their effects on the FRW examined. The first option involved usage of timber DWS; the idea of this option was to use all the primary and secondary members of the FRW in load sharing and to provide additional members where weaknesses in the original members arose. The second option involved usage of reinforced concrete DWS with only the primary members of the FRW sharing the AS5100 (2004) loading. This option inherently minimised the risk associated with any uncertainty of the secondary members to their structural adequacy. This thesis reports the design phases of both options with conclusions of the selection of the ideal option for better structural performance, ease of construction and cost. The comparison carried out here focuses on the distribution of the traffic load by the FRW as a superstructure. Advantages and disadvantages highlighting cost comparisons and ease of constructability of the two systems are also included.

Assessment Of various sensors for structural health monitoring for bridge weigh-in-motion (B-WIM).

In recent years, Structural Health Monitoring (SHM) systems have been developed to monitor bridge deterioration, assess real load levels and hence extend bridge life and safety. A road bridge is only safe if the stresses caused by the passing vehicles are less than the capacity of the bridge to resist them. Conventional SHM systems can be used to improve knowledge of the bridges capacity to resist stresses but generally give no information on the causes of any increase in stresses (based on measuring strain). The concept of in Bridge Weigh-in-Motion (B-WIM) is to establish axle loads, without interruption to traffic flow, by using strain sensors at a bridge soffit and subsequently converting the data to real time axle loads or stresses. Recent studies have shown it would be most beneficial to develop a portable system which can be easily attached to existing and new bridge structures for a specified monitoring period. The sensors could then be left in place while the data acquisition can be moved for various other sites. Therefore it is necessary to find accurate sensors capable of capturing peak strains under dynamic load and suitable methods for attaching these strain sensors to existing and new bridge structures. Additionally, it is important to ensure accurate strain transfer between concrete and steel, the adhesives layer and the strain sensor. This paper describes research investigating the suitably of using various sensors for the monitoring of concrete structures under dynamic vehicle load. Electrical resistance strain (ERS) gauges, vibrating wire (VW) gauges and fibre optic sensors (FOS) are commonly used for SHM. A comparative study will be carried out to select a suitable sensor for a bridge Weigh in Motion System. This study will look at fixing methods, durability, scanning rate and accuracy range. Finite element modeling is used to predict the strains which are then validated in laboratory trials.

BRITE report 2004

This document reports on an innovation survey of the Australian construction industry undertaken by the BRITE Project of the CRC for Construction Innovation in 2004. The survey sample was drawn from 3,500 businesses in the road/bridge and commercial building sectors in NSW, Vic and Qld, covering main contractors, trade contractors, consultants, suppliers and clients. One-third of this population was sampled and a response rate of 30% was achieved. The survey investigates innovation determinants in the industry, comprising various aspects of business strategy and business environment.

Brite innovation survey : executive summary

This report summarises the fi ndings of an innovation survey of the Australian construction industry undertaken by the BRITE Project of the CRC for Construction Innovation in 2004. The BRITE Innovation Survey can be viewed in full at www.brite.crcci.info.The objective of the BRITE project is to improve the incidence and quality of innovation in the Australian construction industry. Many stakeholders in the industry are sceptical about the potential for innovation and its likely benefi ts. Many also lack the linkages and capabilities required for successful innovation. The BRITE Project is redressing this situation through demonstration and benchmarking activities. The term ‘innovation’ is defi ned as a new or signifi cantly improved technology or advanced business practice. Innovation may be technological or organisational, and it may be new to the world, or just new to the industry or business concerned. The defi nition includes the adoption of existing advancements developed outside a particular business. The survey sample was drawn from 3,500 businesses in the road/bridge and commercial building sectors in New South Wales, Victoria and Queensland, covering main contractors, trade contractors, consultants, suppliers and clients. Onethird of this population was sampled and a response rate of almost 30% was achieved. The survey collected information about respondents’ perceptions of innovation determinants in the industry, comprising various aspects of business strategy and business environment.

An experimental research investigation into disused flat rail wagons as bridges with applications for low volume rural roads in Australia

An experimental laboratory investigation was carried out to assess the structural adequacy of a disused PHO Class Flat Bottom Rail Wagon (FRW) for a single lane low volume road bridge application as per the design provisions of the Australian Bridge Design Standard AS 5100(2004). The investigation also encompassed a review into the risk associated with the pre-existing damage in wagons incurred during their service life on rail. The main objective of the laboratory testing of the FRW was to physically measure its performance under the same applied traffic loading it would be required to resist as a road bridge deck. In order to achieve this a full width (5.2m) single lane, single span (approximately 10m), simply supported bridge would be required to be constructed and tested in a structural laboratory. However, the available clear spacing between the columns of the loading portal frame encountered within the laboratory was insufficient to accommodate the 5.2m wide bridge deck excluding clearance normally considered necessary in structural testing. Therefore, only half of the full scale bridge deck (single FRW of width 2.6m) was able to be accommodated and tested; with the continuity of the bridge deck in the lateral direction applied as boundary constraints along the full length of the FRW at six selected locations. This represents a novel approach not yet reported in the literature for bridge deck testing to the best of the knowledge of the author. The test was carried out under two loadings provided in AS 5100 (2004) – one stationary W80 wheel load and the second a moving axle load M1600. As the bridge investigated in the study is a single lane single span low volume road bridge, the risk of pre-existing damage and the expected high cycle fatigue failure potential was assessed as being minimal and hence the bridge deck was not tested structurally for fatigue/ fracture. The high axle load requirements have instead been focussed upon the investigation into the serviceability and ultimate limit state requirements. The testing regime adopted however involved extensive recording of strains and deflections at several critical locations of the FRW. Three locations of W80 point load and two locations of the M1600 Axle load were considered for the serviceability testing; the FRW was also tested under the ultimate load dictated by the M1600. The outcomes of the experimental investigation have demonstrated that the FRW is structurally adequate to resist the prescribed traffic loadings outlaid in AS 5100 (2004). As the loading was directly applied on to the FRW, the laboratory testing is assessed as being significantly conservative. The FRW bridge deck in the field would only resist the load transferred by the running platform, where, depending on the design, composite action might exist – thereby the share of the loading which needs to be resisted by the FRW would be smaller than the system tested in the lab. On this basis, a demonstration bridge is under construction at the time of writing this thesis and future research will involve field testing in order to assess its performance.

The determinants of multinational contractors' willingness to bid for Australian public sector major infrastructure projects : deploying the eclectic paradigm of internationalisation

Based on Dunning's dominant international business theory and the unique characteristics of construction, a novel framework is developed and tested to explain multinational contracting into Australia. Beyond contributions to theory, Australian governments now have clear evidence upon which to develop more effective procurement reform towards increasing the attractiveness of public sector major infrastructure projects and competition in this sector.

Non-destructive structural integrity assessment of a decommissioned rail wagon system

This paper presents a multi-criteria based approach for nondestructive diagnostic structural integrity assessment of a decommissioned flatbed rail wagon (FBRW) used for road bridge superstructure rehabilitation and replacement applications. First, full-scale vibration and static test data sets are employed in a FE model of the FBRW to obtain the best ‘initial’ estimate of the model parameters. Second, the ‘final’ model parameters are predicted using sensitivity-based perturbation analysis without significant difficulties encountered. Consequently, the updated FBRW model is validated using the independent sets of full-scale laboratory static test data. Finally, the updated and validated FE model of the FBRW is used for structural integrity assessment of a single lane FBRW bridge subjected to the Australian bridge design traffic load.