Development of Economical Low‐Volume Road Bridges

Abstract

Low‐volume road bridges are currently designed according to the same specifications as urban highway bridges. Thus, many of the low‐volume bridge designs are overly conservative and uneconomical. This paper addresses this issue and proposes modifications of the existing specifications in the area of fatigue, deflection, allowable stress, composite action of timber decks, bridge width, lane loading, and the use of guardrails. All of the systems selected were combinations of prefabricated components. Jointless bridges received very high rankings and are strongly recommended for the 60‐ft and 100‐ft span ranges. A precast voided slab system and a timber deck and steel stringer system received the highest ranking on the 30‐ft span range. This study proposed a method of selecting the type of bridge system to be built in a particular area and a priority scheme to select which bridges must be replaced first. The scheme models the Federal Highway Administration (FHWA) sufficiency ranking with some of the ranking criteria being changed to better meet the needs of low‐volume road bridges.