FEATURE ARTICLE: Items of special interest, tutorials, and surveys SEISMIC BEHAVIOR OF LOW-RISE WOOD-FRAMED BUILDINGS

Abstract. This article reviews the performance of wood-frame buildings in recent earthquakes, and summarizes research performed to more fully understand their seismic behavior. Past experience has shown that properly con-structed wood-framed buildings can resist the damaging effects of seismic ground motion. Structures that are symmetrical in plan, built of lightweight materials and constructed of components that act as a unit generally perform well. The inherent damping found in wood and nailed and bolted connections also helps in the mitigation of earthquake damage. This paper is a review of recent research that has been performed to quantify the begavior of wood buildings subjected to seismic motion. The focus will be directed towards component response since most recent research has been performed in that area. Low-rise, wood-framed buildings will be emphasized. This type of construction represents most residential and a large numbere of commercial and industrial buildings constructed in the United States. PAST PERFORMANCE Damage to wood buildings resulting from the 1964 Alaska earthquake (8.6 Richter) and the 1971 San Fernando earthquake (6.6. Richter) has been well documented [1-9]. Although the Alas-kan earthquake was of higher magnitude, the damage to wood buildings was less severe than witnessed in San Fernando. The Alaskan homes were more symmetrical in cross section and had smaller openings than their San Fernando coun-terparts. In both events, the primary cause of damage was a lack of adequate lateral support [3,5,6,10, 11]. The San Fernando event indicated that two-story and split-level homes with large garage openings at ground level are particu-larly susceptible to damage. Failures at sill plate connections and homes shifting off foun-dations were also observed. Fuller [2] noted that a deficiency of some buildings was a lack of resistance to torsional racking caused by the second story being stiffer than the first