Abstract

Light-frame low-rise wood dwellings have typically had adequate levels of safety in terms of collapse prevention. Nevertheless, damage to this type of construction due to earthquakes has resulted in large economic losses and thousands of displaced families. This paper evaluates the benefits, on a regional scale, of using a recently developed design and construction method referred to as unibody. This cost-effective method increases the lateral strength and, particularly, the lateral stiffness of walls of wood-frame houses, leading to significant reductions in lateral displacement demands. For houses at a given distance from the seismic source, reduced displacement demands translate into much smaller probabilities of damage. Consequently, for a region affected by a seismic event, this translates into a much smaller area of damaged houses. It is found that, for short-period structures, increasing the lateral stiffness is more efficient than increasing the lateral strength. Thus, when using unibody construction, which greatly increases the lateral stiffness of wood-frame houses, the number of damaged residential units is greatly reduced. It is shown that these relationships are strongly nonlinear and are positively combined resulting in a substantial reduction of seismic risk on a regional scale.