Author: Justin R. Vander WerffPublisher:
ISBN:
Category :
Languages : en
Pages : 368
Book Description
Bridges with integral connections exhibit improved seismic performance and are useful in providing increased clearances. Integral bridges with steel girders are feasible and provide decreased seismic mass to further enhance seismic performance. However, most bridges in seismic regions that have been built with integral connections have been designed with concrete superstructures and concrete cap beams, and most of the research that has been conducted on integral connections for seismic regions has also dealt with concrete cap and girder sections. For this reason, the National Cooperative Highway Research Program has funded a project investigating the performance of concrete columns and steel superstructures in integral pier bridges under seismic loading. The focus of the project involved the development of a prototype bridge, investigation of suitable connection details and optimum member dimensions, load distribution in the structure, and overall seismic performance. These areas were examined using a combination of analytical and experimental studies. The prototype bridge developed in this study consists of a concrete column; steel, box-shaped cap beam; and steel girders. Two one-third-scale test specimens were developed, constructed, and tested as part of the experimental investigation. Grillage analyses of the prototype structure and test specimens were developed to work out appropriate loading for the specimens, to analyze the load distribution in the structures, and to develop predicted responses for the test specimens. The design of the first test specimen was governed by geometrical constraints based on the necessary depth to provide adequate anchorage length for the column longitudinal reinforcement. The second test specimen was designed to optimize the efficiency of the superstructure by using mechanical anchorage for the column longitudinal reinforcement, allowing the use of a shallower cap beam and lighter girder sections. Both test specimens exhibited satisfactory seismic performance by developing plastic hinges in the columns and successfully retaining strength under inelastic deformations.
