مهندسی عمران شریف (May 2022)
EVALUATION OF SEISMIC BEHAVIOR OF SMRFs WITH AND WITHOUT STEEL SHEAR WALL AGAINST SEQUENCING EARTHQUAKES
Abstract
A better understanding of the dynamic behavior and seismic performance of structures has led to advances in structural design in recent years, but despite recent advances, many existing structures are not earthquake resistant. Steel Moment Resisting Frames (SMRFs) are one of the common structural systems in construction that has been considered by engineers due to its ease of implementation, relatively good seismic behavior and architectural considerations. However, Steel Moment Resisting Frames, in addition to being costly and performing defects in joints, has a low lateral stiffness compared to other strong systems and does not have good resistance to high horizontal displacement and structural and non-structural elements are exposed to damage. Near-fault Earthquakes are among the factors that increase damage to the structure and also intensify lateral load intensity. In this paper, the seismic behavior of SMRFs with and without Steel Plate Shear Walls (SPSWs) against 40 artificial near and far fault seismic records are evaluated using nonlinear time history analysis. For this purpose, 8-, 15- and 20- story frames were designed without considering the permissible drift criteria. Then, a steel shear wall was added to the frames and while redesigning, the drift criterion was met. The results show that in both cases with and without SPSWs the need for seismic near the fault sequences is greater than the far fault seismic sequences. The presence of SPSWs reduces the need for deformation (except for absolute floor acceleration), and this effect is more pronounced for near faults scenarios. In all cases, the presence or absence of SPSWs has no effect on the maximum floor acceleration. Adding SPSWs always increases the need for base shear force, but the force is still more significant from near fault than far fault scenarios. The results of comparing the effect of successive earthquakes near and far from the fault show that near-fault earthquakes always act to increase the need for the structure.
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