Quality Control in Seismic Design and Construction

This paper presents research on quality control in seismic-resistant construction. The research objective was to verify compliance with seismic safety features in light residential and commercial wood construction. While the study was on quality control in seismic-resistant construction, the results apply to wind conditions and design flaws as well. The study included two methods: (1) mail surveys of architects and engineers; and (2) site surveys of projects under construction. Results are presented in graphs for visual comparison. Both surveys revealed that more than one-third of seismic safety items were missing or flawed in over 40 of surveyed units (apartments, etc.). It is alarming that the key items to resist wind and seismic loads are among those most frequently missing or flawed, including shear wall hold-downs, nailing, and proportion (aspect ratio); wall-to-wall straps and tie-downs, diaphragm blocking and nailing, drag strut splice, and roof-to-wall anchors. Conclusions include recommendations to improve quality control.