National Center for Wood Transportation Structures

About the research

Lateral slide–in bridge construction (SIBC) has gained increasing attention as a viable accelerated bridge construction (ABC) approach. With lateral slide construction, the majority of the bridge superstructure is constructed off alignment, typically parallel to the final position, and usually on a system of temporary works.

While many state departments of transportation (DOTs) have completed lateral slide construction of single–span bridges and have common connection details already established, these details do not directly apply to multi–span slides. The addition of more spans creates a more complex system that require connections (and other details) that were previously not needed in a single–span slide. In addition, the fact that the multi–span bridge needs to slide on abutments plus piers (as opposed to just abutments) creates possible uplift and overturning scenarios.

A comprehensive literature search was conducted to find relevant information on the implementation of SIBC on multi–span bridges. However, limited public information was found that directly related to the substructure behavior subject to the lateral slide load. An analytical simulation was conducted to investigate the structural behavior of the bridge piers during the bridge slide–in and to evaluate the drawbacks and advantages of two– and four–point pushing.

A finite element (FE) model was developed and validated against the data collected from a field monitored bridge. The results indicated that two–point pushing increases the loading on the pier diaphragm by 36%. Because of this, the pier response with respect to the tilt about the x and z directions increased; however, this increase was not significant. By analyzing the field and analytical solution results, it was also found that the bridge pier experienced a greater rotation about the bridge transverse direction than about the longitudinal direction.

The results of the FE modeling and the literature search resulted in unanswered questions that would benefit from further study. A detailed research plan including a series of laboratory tests is presented in the Phase I report.