ASSESSMENT OF PRECAST WIDE U BEAM-COLUMN SYSTEM FOR MITIGATION OF STRUCTURAL FAILURE FROM SEISMIC HAZARD IN THAILAND

Abstract

A large number of low to moderate earthquake incidents have been witnessed in the northern and western parts of Thailand. These incidents usually lead to various damage levels in various structures. Therefore, a sufficient lateral force resisting structures should be designed for the construction in such earthquake-prone areas. This paper presents the relevance of using a typical composite wide U beam-column system for mitigation of structural failure and collapse from the seismic hazard in Thailand. The investigated composite structural system consists of precast U beams, precast columns, and cast-in-situ concrete over the precast U beams and in the joint regions. The system also includes post-tensioning in the cast-in-situ area of the composite beams. The system has widely been used in low- to mid-rise commercial building in Thailand. In order to scrutinize the seismic performance of the system, a half-scale specimen of the post-tensioned precast U beam-column joint was tested under an incremental displacement-controlled lateral cyclic load. The laboratory test revealed the drift capacity, damage pattern, strain development in the rebars etc. of the precast wide U beam-column interior joint. Based on the obtained drift capacity, displacement-based assessment of the system was carried out. In addition, the observed damages on the tested structure were evaluated using damage grading criteria for building subjected to earthquake. The assessment showed a high potential of the post-tensioned precast wide U beam-column system to mitigate the structural failure and collapse from the earthquake hazard. However, some improvements in the current seismic performance of the system are required to employ the system in high seismic zones.