Deformation Design Guidelines of Retrofitted Deep Coupling Beams by Restrained Bolted Steel Plates

Abstract

Existing deep reinforced concrete (RC) coupling beams with low shear span ratios and conventionally reinforced shear stirrups tend to fill in a brittle manner with limited ductility and deformability under reversed cyclic loading. Experimental and numerical studies have demonstrated the effectiveness of laterally retrained steel plate (LRSP) retrofitting method in improving the seismic performance of deep RC coupling beams. In this way, the deformability and energy dissipation of the retrofitted beams are greatly enhanced. Based on the experimental studies and numerical simulation of LRSP coupling beams, an original deformation design procedure of LRSP coupling beams is proposed. The proposed design guidelines consist of seven parts, which are (1) estimation of shear capacity of RC component, (2) estimation of plate size, (3) estimation of axial force, (4) bolt group design, (5) rotation capacity of bolt group, (6) rotation capacity of steel plate, and (7) rotation compatibility of retrofitted coupling beam.