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 constructed, 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 two alternate structural systems 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 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, 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 some selected results of the experiment as well as the design phases of both options with conclusions of selection of the ideal option for better structural performance, ease of construction and cost.