Finite element modelling of modular precast composites for railway track support structure : a battle to save Sydney Harbour Bridge

Railway networks in Australian alone require replacing a large amount of aging timber components in excess of 280,000 m3/a. The replacement of timber track components is responsible for producing greenhouse gas emissions six times greater than equivalent reinforced concrete counterparts. Sydney Harbour Bridge presently experiences similar problem. A feasibility study to develop an innovative solution for the replacement of aging timber transoms installed on the Sydney Harbour Bridge was conducted to evaluate environmental, safety and fmancial benefits. The development of alternative composite structure to replace llze timber components overcomes some potential compatibility issues with track stiffness as well as structural and geometrical/rack systems. This study firstly presents a novel and resilient alterative by incorporating steel-concrete composite theory and combining the capabilities of being precast and modular, in order to reduce the depth, weight and required installation time relative to conventional concrete track slab systems. Finite element analysis of the composite structures and its behaviours incorporating the bridge system are highlighted in this paper. A three-dimensional model of steel-concrete composites was developed by using ABAQUS. Non-linear material properties and contact inteifaces have been simulated to mimic actual support conditions of existing stringers on the Sydney Harbour Bridge. This investigation demonstrates the safety of the composite panels under train derailment loads.