Date of Award
Summer 2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Civil, Construction, and Environmental Engineering
First Advisor
Andrew Sen
Second Advisor
Baolin Wan
Third Advisor
Jamie Hernandez
Abstract
Special concentrically braced frames (SCBFs) and ordinary concentrically braced frames (OCBFs) are seismic-force-resisting systems often used in steel building construction. Previous research has shown that lower brace width-to-thickness ratios delay brace fracture during cyclic inelastic loading that is typical during moderate-to-large earthquakes. To ensure adequate seismic performance, SCBF and OCBF brace shapes are thus limited by the highly and moderately ductile width-to-thickness ratio limits, respectively, presented by the American Institute of Steel Construction Seismic Provisions for Structural Steel Buildings. To justify these limits, system-level analysis of SCBFs and OCBFs during high seismic events is needed. This study uses nonlinear response-history analysis to evaluate the deformation demands and collapse performance of these systems using square hollow-structural-section braces. Study buildings are designed with variations of brace configuration and number of stories for comparable SCBF or OCBF systems. An alternative set of OCBFs designed with a relaxed brace width-to-thickness ratio limit is also analyzed . These systems are designed for a generic site in Seismic Design Category D and are subject to a ground motion suite that was scaled to both the MCER and the back-calculated, minimally acceptable ŜCT based on the FEMA P-695 standard. Drift, brace, and column demands are collected from these analyses, which are utilized to develop target force and deformation capacities for these systems. Collapse performance is also evaluated and used to inform recommendations for modifications to the Seismic Provisions.