BRIDGE REPLACEMENT ALTERNATIVE FOR LOW VOLUME ROADS

In Iowa there are over 20,000 bridges on the secondary system. The majority of these bridges are the responsibility of the local county engineers. As county engineers have limited budgets, in many counties the engineers design and construct their own short span bridges with their own labor forces. The primary objective of this research is to perform laboratory testing on two bridge alternatives (Concept 1 and Concept 2) that counties can design and construct with their own crews. Concept 1 involves the fabrication of precast units which consist of steel beams connected compositely with a concrete deck. Deck thickness is limited so that the units can be lifted and transported to the field where several of these units can be connected and the remaining portion of the deck placed. Concept 2 involves testing and modifying a system of steel beams with concrete fill between them that has been used by several Iowa counties on low water stream crossings for 20 pIus years. There is no reinforcing steel in this system or connection between the steel beams and the concrete. Due to page restrictions, only Concept 1 is presented in this paper. For the covering abstract see ITRD E111699.