Bridges

As part of the NACOE research project ‘Deck unit bridge deck analysis under live load’, a comprehensive load testing program has been conducted in Queensland to investigate the behaviour of transversely stressed precast prestressed concrete deck unit bridges. The project seeks to address the disparities between theoretical assessments and actual performance of deck unit bridges and provide input for developing consistent guidelines for analysis to ensure that rating and assessment results of existing bridges are accurate. In order to achieve this, responses of in-service bridges and ultimate strength/capacity of deck units need to be determined and/or confirmed through load testing.

The test program includes load testing of an in-service bridge under controlled loads and random traffic, destructive testing of individual deck units in bending and shear, and testing to failure of a part bridge built in a laboratory using decommissioned deck units. Results obtained from the test program provide in-depth knowledge of the behaviour of this type of bridge under service live loads as well as at high loading levels up to failure. Particularly, information on the load transfer mechanism between the units, the failure modes of individual units and of the bridge as a whole, and the effects of transverse stressing on the overall performance of the bridge, is of interest. The test results will be used to calibrate computer grillage models to improve the accuracy and confidence in modelling and theoretical predictions of these structures.

This paper provides a summary of the test program and discusses key findings to date.