Seismic Retrofitting Effect of RC Buildings using Perimeter Steel Moment Frames

Abstract

This paper investigates the retrofitting effect for a non-ductile reinforced concrete frame strengthened by perimeter steel moment frames with indirect connection, which ameliorates the direct connection’s problems. To this end, first, full-scale tests were conducted to address the structural behavior of a two-story reinforced concrete frame with non-seismic details (non-seismic specimen), and a WAS seismically strengthened frame (WAS specimen) per the Korean rehabilitation manual. The non-seismic specimen showed a maximum strength of 185.5 kN because the flexural-shear failure at the bottom end of columns on the first floor was governed, and shear cracks were concentrated at the beam-column joints on the second floor. The WAS specimen possessed more than 1.82 times lateral-resisting capacity. A considerable decrease in the number of cracks for the WAS specimen was observed, while there was the apparent appearance of the fracture pattern due to shear cracks. The lateral-resisting capacity of the non-seismic and WAS specimens might be reasonably determined per the reinforced columns’ specified shear strength following the distance to a critical section. The critical section for the WAS specimen was defined. The ultimate strength design methods for the non-seismic and WAS specimens based on the closed results versus the experimental results were proposed.