Field investigation of joints in precast post-tensioned segmental concrete bridges

Abstract

The precast segmental construction is widely used in the bridge structures erected by balanced- cantilever method. The joints are obviously of the utmost importance in connecting the precast segments of bridge girders. As well as the girders, the joints between segments should be capable of transferring compression, shear, and torsion forces. The basic requirements for match-cast joints are summarised. The joints between segments in many precast concrete bridges constructed by balanced cantilever method were inspected during construction and in service. The results of field survey that are presented in this paper included 5 major bridges. The spans are all precast box girders of constant or varying cross-section. Studies were conducted to determine the geometry and mechanical properties of grouted and match-cast joints. Classification of joint defects is presented. Statistics are given on the defects observed in some box-girder segmental joints. Photographs of typical joint problems are included.