Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 56 8 2024 10 22 Seismic performance evaluation of RC bridge piers designed with direct displacement-based design Seismic performance evaluation of RC bridge piers designed with direct displacement-based design 1027 1052 5503 10.22060/ceej.2024.22631.8010 FA Alireza Sepahvand Department of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran Horr Khosravi Department of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran 0000-0002-8972-4894 Journal Article 2023 08 27 In Direct Displacement-Based Design (DDBD), the performance objective is to achieve the design displacement (target displacement), and the stiffness and strength of the structure are determined in such a way that the maximum displacement of the structure in an earthquake reaches this displacement. For this purpose, the design base shear is determined based on 3 key parameters equivalent damping, damping modification factor, and P-Delta effect. Due to the variation of relationships for each of these parameters, in this study, the influence of using different relations on achieving performance objectives is investigated. In this study, 8 bridge piers with 2 different heights, 2 different span lengths, and 2 seismic hazard levels were selected. In order to design the piers, the displacement design spectra were extracted from AASHTO acceleration design spectra. Then, each of these piers was designed for 27 different design paths resulting from 3 distinct relationships for each of the 3 key parameters, and a total of 216 bridge piers were designed by the DDBD approach. Then, to evaluate the seismic performance of the piers, each of the 216 piers was modeled in OpenSees software and subjected to 14 far-field earthquake records scaled on the design spectrum. After determining the maximum displacement of each pier, the proximity of this displacement to the target displacement was studied as a performance objective indicator. The results of the analysis show that the use of different design relations has a significant effect on the maximum displacement of piers and their construction cost. So for the most designed bridge piers, the use of different relationships causes a 20% decrease or increase in the maximum displacement compared to the target displacement and up to 40% changes in the construction cost. Among 27 design paths, using the Priestley relationship for equivalent damping, the Japanese regulation formula for the damping modification factor, and the Pettinga and Priestley formula for the P-Delta effect, provides a more suitable performance for all bridge piers designed with different heights, different span lengths and different seismic hazard levels. In Direct Displacement-Based Design (DDBD), the performance objective is to achieve the design displacement (target displacement), and the stiffness and strength of the structure are determined in such a way that the maximum displacement of the structure in an earthquake reaches this displacement. For this purpose, the design base shear is determined based on 3 key parameters equivalent damping, damping modification factor, and P-Delta effect. Due to the variation of relationships for each of these parameters, in this study, the influence of using different relations on achieving performance objectives is investigated. In this study, 8 bridge piers with 2 different heights, 2 different span lengths, and 2 seismic hazard levels were selected. In order to design the piers, the displacement design spectra were extracted from AASHTO acceleration design spectra. Then, each of these piers was designed for 27 different design paths resulting from 3 distinct relationships for each of the 3 key parameters, and a total of 216 bridge piers were designed by the DDBD approach. Then, to evaluate the seismic performance of the piers, each of the 216 piers was modeled in OpenSees software and subjected to 14 far-field earthquake records scaled on the design spectrum. After determining the maximum displacement of each pier, the proximity of this displacement to the target displacement was studied as a performance objective indicator. The results of the analysis show that the use of different design relations has a significant effect on the maximum displacement of piers and their construction cost. So for the most designed bridge piers, the use of different relationships causes a 20% decrease or increase in the maximum displacement compared to the target displacement and up to 40% changes in the construction cost. Among 27 design paths, using the Priestley relationship for equivalent damping, the Japanese regulation formula for the damping modification factor, and the Pettinga and Priestley formula for the P-Delta effect, provides a more suitable performance for all bridge piers designed with different heights, different span lengths and different seismic hazard levels. https://ceej.aut.ac.ir/article_5503_4b85256c4881edb6c0776df5d81f6236.pdf