Experimental and Numerical Investigation of Steel Moment Resisting Frame with U-Shaped Metallic Yielding Damper

This study introduces U-shape metallic yielding damper (UMYD) as an energy dissipation system. This damper may be used as a replaceable and cost-effective tool and fuse in structural frames to improve lateral ductility, energy absorption and damping of structural systems under earthquakes. A series of static cyclic tests were conducted in order to examine the performance of UMYD and the response of force-displacement, lateral strength, elastic stiffness and energy absorption were achieved. Finite element numerical studies were conducted through changing damper geometrical parameters. Mathematical model was presented to estimate elastic stiffness of damper and was compared with numerical specimen results, which acceptable conformity. Finite elements models indicated that UMYD abilities energy absorbability in large displacements without loss of strength and stiffness, which may be a proper complementary system for lateral load-bearing systems. The behaviour of two 4- and 8-storey steel frames with moment resisting frame system was analysed under four different earthquakes under two states of with and without damper. The seismic performance of frames was analysed with respect to floors inter-storey drift, frame base shear and floors shear. The non-linear time historey analysis results demonstrated that 8-storey frame without UMYD failed to maintain the structure performance level within life-safety level, whilst under all states using damper, performance level remained within such level and a decrease in floors shear and inter-storey drift was observed.