Thesis Defense: Hamid Foroughi, “Enhancing Seismic Resiliency of Steel Buildings through Three-Dimensional Modeling of Diaphragm System Interaction with Braced Frame”
THE DEPARTMENT OF CIVIL AND SYSTEMS ENGINEERING
ADVISOR BENJAMIN SCHAFER, PROFESSOR
ANNOUNCE THE THESIS DEFENSE OF
Friday, February 19th
Contact Elena Shichkova for access to this presentation.
“Enhancing Seismic Resiliency of Steel Buildings through Three-Dimensional Modeling of Diaphragm System Interaction with Braced Frame”
Steel deck diaphragms have a number of benefits such as low weight, competitive cost and a wide range of stiffness (from bare deck to composite floor systems). However, steel diaphragm design lacks a design paradigm consistent with seismic performance-based design. To consider the diaphragm system as an integral part of the building, and not just as a distribution element, the seismic performance of steel braced frame buildings can be assessed through material and geometric nonlinear dynamic analysis. Extensive efforts have been conducted in the past, employing 2D building models, and dynamic analysis to predict the collapse probability of steel building and justify seismic response modification coefficients (e.g., R) employed in equivalent lateral force-based design procedures. Little work has been performed on 3D building models where the vertical lateral force resisting system (LFRS) may interact with the floor diaphragm. This work aims to develop fundamental understanding of steel deck diaphragms as structural systems integrated within the overall building performance and improve strategies for accurate modeling of floor systems to enhance the overall structural resilience of the building. To achieve the research objectives, different diaphragm design scenarios based on ASCE 7-16, are investigated for a series of 1, 4, 8, and 12-story archetype buildings with special concentrically braced frame (SCBF) as vertical lateral force resisting system. FEMA P-695 methodology is used to assess the seismic performance of SCBF archetype buildings with different diaphragm response modification factor, Rs, that accounts for diaphragm ductility and propose a reasonable Rs values for the steel braced frame buildings.