Preliminary construction cost estimates for motorway underpass bridges

This paper presents the total cost and cost distribution between activities required for the construction of reinforced concrete underpass bridges. The required material quantities of concrete, reinforcing steel, earthworks (excavation, soil improvement layer and backfilling), waterproofing works, joint formation and drainage system from 34 closed box section and slab frame underpasses from recent highway projects in Greece are statistically processed. Following analysis of this data, preliminary cost estimating formulae for underpass bridges are proposed based on the overpass deck surface area and a new parameter called the theoretical volume. The theoretical volume is a known value even at the preliminary stage of design as it is essentially the dimensions of the local road that must be realigned to underpass the motorway. It is suggested that the use of the proposed formulae will provide decsion-makers with accurate cost estimated of reinforced concrete motorway underpass bridges.