Seismic performance of precast concrete segmental bridges: Summary of experimental research on segmentto-segment joints

Abstract

Segmental construction of precast concrete bridges can accelerate construction and minimize the cost of bridges in congested urban environments and environmentally sensitive regions. Despite proven benefits, the use of precast concrete segmental bridges in e seismic regions of the United States remains limited. A main obstacle to their use is concern regarding the seismic response of segment-to-segment joints. To address this concern, researchers recently completed a three-phase research project to investigate the seismic performance of precast concrete segmental bridges. The first and second phases of the project studied the performance of precast concrete segments in superstructure regions of high moment-low shear and high moment-high shear, respectively. The third phase of the project investigated the performance of a large-scale, balanced-cantilever, superstructure-pier system under two stages of seismic loading. The first loading stage studied the system performance when the superstructure segment joints were designed to remain closed, per current design practices. The second loading stage investigated the system performance when nonlinear elastic response was permitted in the superstructure. This paper summarizes the major experimental results from all three phases of the research project and will show that segment joints can undergo large rotations that open gaps in the superstructure without significant loss of strength. In addition, this research showed that damage in a superstructure-column system is limited to the column when vertical earthquake demands are not considered. However, when vertical earthquake demands are included and the clamping force at the superstructure segment joints is reduced, some segment joints may open but the behavior of the system is not compromised.