Application of Truss Type Safety Barrier for Increasing Span Length of Temporary Bridges

Recently, environmental issues have been raised in offshore bridge constructions, which requires constructing temporary bridges in shallow water levels instead of temporary embankment roads. Therefore, this has significantly increased the amount of trestle required in offshore bridge projects. Due to limitations in using marine equipments to approach shallow waters, the phased forward method needs to be implemented in constructing a trestle in shallow waters. However, depending on the capacity of the crane, the phased forward method restricts the span length of the trestle, which would critically increase the construction period. Therefore, in order to perform offshore bridge projects, more competitive approaches are required to reduce the construction period and the quantity of trestle through optimized designs. This research adopts high strength steel and truss type safety barrier as members to control deflection and propose ways of elongating the span of the trestle. Under the same conditions, the application of SM490 steel and truss type safety barrier enable the trestle span to increase up to 21 m. In addition to considering a trestle at a total length of 1050 m, the proposed approach can reduce the number of spans by 33% and decreasing the quantities of sub-structures and the construction period by approximately 2 months.