Window Glass Failures in Windstorms

Abstract

Documentations of windstorm induced damage to buildings have revealed patterns of failures in glass which suggest that two phenomena are at work: local wind pressures and windborne missiles. Analysis of damage to glass indicate that these two phenomena account for a large portion of the recorded damage. Phenomena associated with wind flow around multistory buildings produce relatively large surface pressure fluctuations on building surfaces. The mean pressures produced by these fluctuations may reach values which are twice as large as windward wall stagnation pressures. Air flow over gravel surfaced roofs in urban areas has been shown to produce windborne missiles which can break windows in adjacent buildings. This phenomenon is a significant factor in many window breakage incidents. Both local wind pressures and hazards associated with windborne missiles must be recognized by the building designer if the increasing window failure rate is to be mitigated.