Inelastic Analysis of Steel Moment Resisting Frames in Light-Framed Wood Buildings

Abstract

INELASTIC ANALYSIS OF STEEL MOMENT RESISTING FRAMES IN LIGHT-FRAMED WOOD BUILDINGS by Matthew D. Knutsen A preliminary quantitative analysis of steel moment resisting frames as the lateral force-resisting system for light-framed wood buildings was completed to identify issues requiring more advanced study. A two-story prototype building was evaluated. The lateral force-resisting system of the building contains intermediate steel moment frames with reduced beam section (RBS) connections, wood glulam collectors, and wood structural sheathing diaphragms. Building configuration and cross-sectional properties were assumed based on visual observation and typical design standards for local construction. A simplified pushover analysis and a traditional nonlinear pushover analysis were performed on the typical moment frame. It was determined that a total lateral load of 103 kips on the frame would cause first yielding of the RBS connections with the ultimate strength of the framing being 133 kips. This load was compared to the lateral loads expected to be generated by the seismic masses tributary to the various steel moment frames. An additional comparison was made with the collector design loads. It was determined that the largest tributary seismic mass in the building would be expected to cause the supporting frame to yield. Assuming that all collectors in the building were designed for the highest collector design load, the collectors also would have adequate capacity to transfer the lateral load required to yield the assumed IMF.