Light-Frame Design Aids: Correlating Seismic Forces and Wind Rocking Forces

摘要

This report summarizes seismic provisions of the Uniform Building Code and the American National Standards Institute (ANSI) and recommendations of the Applied Technology Council as they apply to the main frame resisting system of one -, two -, and three - story light - frame timber buildings. Then, curves are presented for several typical wood buildings to correlate seismic loads with windloads to determine which will govern the design in a given geopraphic location with specific code jurisdictions. Generalization of these curves is limited to buildings that are symmetric and rectangular in plan, with 9 - foot story heights and equal lumped mass at each story. For horizontal wall racking design, equivalent pressures decrease considerably as roof slope increases, implying that the windload may govern the design of a steep - sloped building whereas seismic may govern the same building with a flat roof. Higher stories receive proportionately more of the seismic base shear than lower stories. Thus, seismic may govern the shear wall design of the upper stories and wind may govern that of the lower stories in a two - or three - story building. References, tables, graphs, and sample problems are included. (Author summary modified).