Below-Grade Structurla Flexibility Study for Seismic-Resistant, Self-Centering, Concentrically-Braced Frames

Abstract

Self-centering, concentrically braced frames (SC-CBFs) are seismic-resistant lateral-load resisting systems for buildings that increase the lateral drift capacity in comparison to conventional CBFs. Two different substructures were examined on a six-story and a ten-story building to see which below grade structure was more efficient and how the flexibility from the addition of a basement compares to previous research of SC-CBFs structures without basements. The study was completed in phases: modeling of forces in SAP2000, sizing of structural members, coding of structure into the modeling program Open System for Earthquake Engineering Simulation (OpenSees), and comparison of the output data. Substructure one proved to be the more efficient geometry choice for the basement design. Substructure two had similar results as substructure one for the 6-story model, but proved to add excessive flexibility when the geometry was examined on the 10-story model