Estimation of yield displacement of steel bending frames with elliptical bracing, required in displacement-based direct design method

One of the important parameters in the process of calculating the basic shear force in the direct design method based on displacement is the estimation of the displacement displacement based on the geometric characteristics of the structure. In this article, an attempt has been made to investigate the relationship between displacement and yield of steel structures with elliptical bracing in the direct design process based on displacement. For this purpose, 24 models of bending frames with oval braces with different number of floors 6, 9, 12 and 15 floors, with different number of openings 3 and 6 openings have been studied. The various analyzes performed include non-linear static analyses, non-linear dynamic analyzes with seven artificial acceleration maps and seven natural acceleration maps according to the design spectrum of the structures. SAP2000 software has been used for the design and analysis. The obtained results show that for structures with 6 floors and above, this relationship should be reduced by 30%.The basic philosophy in the displacement-based direct design method is that structures should be designed to achieve a specified level of performance, this performance level can be defined by specifying strain limits or relative lateral displacement under the effect of specific hazard levels. In fact, this method can be considered a step-by-step method leading to the limit forces of the members. In this method, instead of using the characteristics of the original multi-degree-of-freedom structure, an alternative single-degree-of-freedom structure with inelastic characteristics of the original structure is used.