Improved Seismic Design Procedure for Concrete Bridge Joints

Abstract

Experimental investigation and subsequent analytical studies have shown that the external strut force transfer method of design is insufficient for reinforced concrete bridge joints and overly conservative for prestressed joints, particularly under in-plane seismic loading. Despite these findings, this design method is widely endorsed for use in seismic design practice in the United States. In consideration of the shortcomings of the currently used force transfer model for bridge joints, an improved design model, referred to hereafter as the modified external strut force transfer model, is introduced in this paper. Use of the modified model for bridge tee and knee joints, design equations, a set of prescriptive design steps in a readily applicable form, and reinforced and prestressed concrete bridge joint design examples are also presented.