Experiments on flexural strength on composite modular bridge pier cap for CFT columns

Abstract

Modular bridge substructures consisting with Concrete-Filled steel Tube (CFT) columns, composite precast segments have been suggested to accelerate bridge construction. The precast segmental pier cap consists of a composite pier table and prestressed precast concrete segments on the table. The pier table has embedded steel sections to mitigate stress concentration at the connection between concrete pier cap and small steel tubes. The shear strength of the pier cap was obtained by extending vertical reinforcing bars from the table to the precast segment. Transverse prestressing was introduced to control tensile stresses of the segments with service loadings. Structural performance of the proposed modular system was evaluated by static tests. Test results showed that the horizontal shear force from the vertical load should be resisted by bond, friction and vertical reinforcements crossing the interface. When the anchorage of vertical reinforcements and preventing of premature fracture of prestressing steels were provided, the flexural strength of the pier cap module at the joint location showed reasonable prediction.