SEISMIC PERFORMANCE OF CODE-DESIGNED FIBER-REINFORCED CONCRETE JOINTS

An experimental investigation is presented on the use of steer fiber r einforced concrete to provide ductility in beam-to-column joints durin g earthquake excitation; Four full-scale exterior beam-column joints, part of a prototype building designed according to the National Buildi ng Code of Canada, were tested under cyclic reverse loading. The first specimen was made of normal concrete but ignored all the special seis mic recommendations related to the spacing of lateral reinforcement in the beams, columns and joints. The second specimen was also made of n ormal concrete and incorporated full seismic details. The third and fo urth specimens were similar to the first one but used steel fiber rein forced concrete in the joint region. Experimental results indicated th at fiber reinforced concrete is an appealing alternative to convention al confining reinforcement. Steel fibers bridging across cracks in the concrete mix increase the joint shear strength and can diminish requi rements for closely spaced ties. The performance of a joint is closely related to the volume content and aspect ratio of the fibers.