Seismic Assessment of Buildings with Prepressed Spring Self-Centering Energy Dissipation Braces

The seismic performance of four- and eight-story steel buildings with prepressed spring self-centering energy dissipation (PS-SCED) braces was evaluated using a proposed nonlinear mechanical model. Nonlinear dynamic analyses of conventional steel braced frames (CSBFs) were performed for comparison. Compared with CSBFs, PS-SCED braced frames experienced smaller peak interstory drift, less residual deformation, and lower peak floor acceleration. An orthogonal experiment was used to investigate the influences of three dimensionless design parameters of PS-SCED braces on structural responses. The results indicate that the variation in the ratio of friction slip force provided by the energy dissipation mechanism to the prepressed force of the self-centering mechanism had significant effects on interstory drift and residual deformation of the structure. Additionally, a change in the ratio of postactivation to preactivation stiffness of the PS-SCED brace could elicit significant changes in these two responses. An increase in contact friction between the combination disc springs resulted in a significant increase in peak floor acceleration; therefore, these contact frictions should be avoided when assembling PS-SCED braces. (C) 2019 American Society of Civil Engineers.