Hurricane Related Window Glass Damage in Houston

Abstract

The writers performed an examination of glass damage in a localized downtown Houston area due to the effects of Hurricane Alicia. Indications are that the glass damage occurred even though the windspeeds in the area were probably less than applicable design windspeeds. In addition, results of this investigation suggest that the impact of windborne missiles, primarily roof gravel, was the major cause of the glass damage. This dramatic example of glass damage due to small missile impact is the latest example in a continuing pattern of glass damage due to small missile impact. The fact that roof gravel propelled at relatively low velocities can break all common types and thicknesses of glass has been firmly established in prior research. The reason for the extent of the glass damage in Houston is that applicable building codes and design procedures fail to recognize that windborne missiles are a major cause of glass breakage in windstorms. Specific changes to building codes which will help to reduce the extent of future glass damage are presented in this paper. If these or similar changes are not incorporated into building codes and design procedures, glass breakage will continue to occur in relatively mild windstorms.