An approximate cost estimation model based on standard quantities of steel box girder bridge substructure

Cost estimation during early stages of construction should be swift and accurate. However, approximate estimation of the costs of bridge construction in Korea is flawed because it is calculated using average construction costs per length or area and do not reflect bridge characteristics. For quick and accurate cost estimates of the substructure of steel box girder bridges with minimum input data, this study proposes an approximate cost estimate model that is based on standard quantities of major work items. The data for 52 steel box girder bridges in Korea were collected. 42 bridges were analyzed for the model development and 10 for validation. Five major work items were identified that accounted for 80% or more of construction costs. The developed estimation model utilizes only six input data: overall height of the bridge abutment, number of piers, overall height of piers, types and numbers of bridge shoes, number of locations where steel pipes are used, and length of steel pipe. It shows an error range of -5.78% through +3.93%.