반복하중을 받는 고강도 철근콘크리트 보-기둥 접합부에서 강섬유의 보강효과에 관한 연구

Abstract

Modern buildings are becoming taller and larger, and thus the use of high strength concrete has been increasingly adopted to produce a slender high-rise building. However, high strength concrete is very brittle which may not be acceptable for seismic design. The use of steel fibers in reinforced high strength concrete beam-column joints can improve seismic performance of beam-column joints and reduce the amount of joint transverse reinforcement that greatly complicates reinforcing fabrication in the joint with seismic details. To investigate the characteristics of reinforced high strength concrete beam-column joints using steel fibers and minimal joint transverse reinforcement, seismic testing of ten beam-column joint subassemlages was performed by applying two reversed cycles at each cycle up to 19 cycles. The primary variable was the amount of steel fibers and joint transverse reinforcement. The results of tests indicate that the seismic performance of the beam-column joints were improved with the application of steel fibers with 1 to 1.5% volume fraction that might replace at least one layer of closed joint transverse reinforcement, as the crack width control, load capacity, energy dissipation capacity, joint shear strength and ductility were better due to the steel fibers. Also, a new shear strength equation for a beam-column joint with steel fibers and minimal transverse reinforcement is proposed.