ASSESSMENT OF THE EFFECTIVE PARAMETERS ON DIRECT DISPLACEMENT-BASED DESIGN OF STEEL MOMENT RESISTING FRAMES

Abstract

Direct displacement-based design (DDBD) method as one of the new performance-based earthquake engineering methods has been developed widely in the recent years. Although DDBD method provides a suitable framework for seismic design, it is not economically viable in some cases. In this paper, the assumptions used in DDBD method are assessed and their effects on the results are discussed. Seismic performance of 6, 10, 12, 15 and 20-story steel moment resisting frames designed based on force-based design (FBD) and DDBD methods is compared using pushover analysis and nonlinear time history analysis first. In addition, the material usage of the designed frames are compared. Using the results of nonlinear time history analyses, important parameters that affect the structural performance of DDBD frames have been identified using sensitivity analysis. Results show that although DDBD method has been able to improve the seismic performance of the designed frames, it is not economically efficient for short and medium-rise frames compared to FBD method. On the other hand, not all the assumptions used in DDBD method agree with the nonlinear time history analyses results. Also, based on sensitivity analysis results, higher mode drift amplification, beam depth, yield displacement, equivalent viscous damping ratio and dynamic amplification of column moments have the greatest effect on the frame weight respectively. Results clarify that DDBD method assumptions need some improvement to optimize its results. © 2024, International Association for Earthquake Engineering. All rights reserved.