Bridges form a vital link in the physical infrastructure and must be maintained in a "safe working order" at all times. It is estimated that there are currently 20,000 timber road bridges in service throughout Australia. Increasing demands on these bridges due to heavier and faster moving loads, together with deterioration are placing these aging structures at a higher risk of collapse. Unfortunately, many local governments and government departments have neglected the benefits of preventative maintenance and have opted for "just in time" repairs. This is especially true for timber bridges. This past neglect has placed bridge stock in a poor state that is only now being recognised as a significant problem. A key component of this research is to develop improvements to this current situation. This research thesis generates detailed knowledge on the load carrying capacities of timber bridges and new non destructive testing techniques that can be substituted for conventional testing procedures. For the first time guidelines have been developed for undertaking capacity assessment on timber bridges by specifying intervention levels for notched timber and limiting maximum allowable strains in timber members. This newly acquired knowledge will enable Asset Managers to more accurately determine the capacity of sniped timber bridge girders to enable appropriate retrofitting and maintenance while also allowing the safe movement of heavy vehicles. The knowledge generated through destructive testing of timber girders and the analysis of the vast amount of experimental data has enabled the first instance of developing specifications for replacement girders. These specifications detail both functional and performance related targets for three different types of replacement girders. Testing of these replacement girders also demonstrates that through some minor modifications that the specification targets can be met. The outcomes of this thesis provide an innovative approach to accessing the condition and capacity of timber girders and to increasing the safety and life of timber bridges in Queensland. By using new techniques such as Non-destructive testing, species identification and limiting maximum allowable strains, as described in this thesis, the road transport network can be safety used by heavy and permit vehicles. It is only through the effective management of timber bridge maintenance and rehabilitation that Australia can have an efficiently running road transportation network.
| Identifer | oai:union.ndltd.org:ADTP/265834 |
| Date | January 2008 |
| Creators | Wilkinson, Kym |
| Publisher | Queensland University of Technology |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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