International Institute of Earthquake Engineering and Seismology Journal of Seismology and Earthquake Engineering 1735-1669 27 1 2025 01 01 Effect of Composite Action on Seismic Response of Steel Structures with Dampers Designed by the DDBD Method 89 102 716066 10.48303/jsee.2024.2034260.1110 EN Seyed Behdad Alehojjat Researcher in Structural Engineering, Department of Civil Engineering, Qa. C., Islamic Azad University, Qazvin, Iran 0000-0003-2450-9381 Masood Yakhchalian Assistant Professor, Department of Civil Engineering, Qa. C., Islamic Azad University, Qazvin, Iran 0000-0003-2672-6187 Omid Bahar Associate Professor, Structural Engineering Research Center, International Institute of Earthquake Engineering & Seismology (IIEES), Tehran, Iran 0000-0002-9655-4512 Journal Article 2024 07 01 This paper investigates two important engineering demand parameters for assessing seismic performance of steel moment resisting frames equipped with linear fluid viscous dampers designed using the modified direct displacement-based design (DDBD) method. These parameters include the inter-story drift ratio (IDR) and the residual inter-story drift ratio (RIDR). For this aim, nonlinear dynamic time history analyses are performed at two seismic hazard levels, involving the design basis earthquake (DBE) and the maximum considered earthquake (MCE). The effects of panel zone flexibility and gravity framing are modeled in the analyses. In addition, the effect of considering and neglecting composite action on gravity framing and beam elements in moment resisting frames is investigated. The results show that in<br>both cases, the structures designed using the modified DDBD method could acceptably meet the performance target IDR limit. Additionally, it is shown that accounting for the effect of composite action leads to a reduction of about 4% in the maximum value of mean IDRs at both the DBE and MCE hazard levels. However, an increase of up to 12% is obtained for the maximum value of median RIDRs at the MCE level when the composite action is considered. https://www.jsee.ir/article_716066_567b7c54f21e7be84ac78c83a2253614.pdf