91-0008 Nonlinear Analysis of Steel Frames with Semi-rigid Connections Using the Capacity Spectrum Method G.G.Deierlein, S-H.Hsieh, Y-J.Shen, J.F.Abel 1991 Cornell University 96 PB92-113828 15 This report summarizes the development and application of a computer aided system for the inelastic analysis, evaluation, and design of three-dimensional steel frames with semi-rigid connections under static loading. Main components of the work include: 1) development of a model to represent the nonlinear moment-rotation response of partially restrained connections; 2) development of a matrix-based method for incorporating the connection model in a nonlinear finite element program for framed structures; 3) implementation of the connection model in CU-STAND, a workstation based program for interactive analysis and design of steel framed structures; 4) computer implementation of the capacity spectrum method for estimating inelastic seismic response using modal analysis; 5) demonstration of the system for sensitivity studies on the inelastic response of a planar frame with semi-rigid connections. Through a case study, overall frame response is found to be relatively insensitive to variations in the connection response parameters. The case study also includes application of the capacity spectrum method to investigate the inelastic limit state under seismic loading and comparisons are made with results based on equivalent static code-based loading. Semi-Rigid Frames, Nonlinear Response, Computer Programs, Inelastic Analysis, Capacity Spectrum Method, Three Dimensional Frames, Static Loading, Inelastic Response, Steel Frames, and CU-STAND.