Development and Evaluation of New Connection Systems for Hybrid Truss Bridges

摘要

This study focused mainly on prestressed concrete box girder bridges with steel truss web members, also known as Hybrid Truss Bridge (HTB). Previously, French engineers worked to improve the structural efficiency of prestressed concrete box girders by using concrete-steel hybrid subcomponents in an effort to reduce the weight of the superstructure. As a result of these efforts, several HTBs have recently been constructed in Japan and Korea. All of these bridges have unique connection systems between the concrete slabs and web truss members, which dictate the safety as well as the failure behavior of the hybrid girders. Thus, evaluation of both construction and structural safety of the connection systems regarded as an essential step in the design of HTB. In this study, four new connection systems using either hinge devices or T-type perfobonds have been proposed as improvements to the assemblage and to eliminate the need for welding during construction while satisfying load carrying capacity requirements. The static loading tests for six connection specimens in real scale were carried out in order to fully evaluate structural safety of the newly proposed connection systems. Also, a real scale railway bridge specimen with a 20m single span and an embedded hinge connection system was designed and constructed in a structural laboratory to perform for static and dynamic tests. Using this specimen, the possibility of using an embedded hinge connection system in a HTB, both for railway and general roadway usage, was evaluated.