Seismic behaviour of non-seismically detailed interior beam-wide column joints; part I : experimental results and observed behavior.

Abstract

Four full-scale reinforced concrete interior beam-wide column joints with nonseismic detailing and limited seismic detailing were

designed and tested to investigate the seismic behavior of the joints at Nanyang Technological University, Singapore. In this first part of a two-part paper,* experimental observation and results of tests on the four joints under quasistatic cyclic loading simulated earthquake actions are presented. The two variables in the test specimens were the amount of joint transverse reinforcement and the lap splice details for column and beam reinforcement. The overall performance of each test assembly was found to be unsatisfactory in terms of lateral load capacity, stiffness, drift, and displacement ductility.

Two as-built specimens failed at a low displacement ductility level,

while the other two modified specimens reached a limited displacement ductility level. It was demonstrated that even limited seismic detailing could improve the seismic behavior of the joints. Column main bars lap spliced within plastic hinge regions were detrimental. The beams and columns remained essentially undamaged while shear failure formed in the joints. Further comparisons between experimental and analytical work are given in a companion paper.