Wind Related Failures of Temporary Construction Installations

The intent of the paper is to instigate a discussion on the adequacy of wind design and construction practices for temporary installations such as scaffolds, formwork or sidewalk sheds. The paper presents data collected on incidents ranging over a period from January 2006 to July 2009. It describes patterns of collapse for various types of installations following gusts in the range of 40 to 60 mph, significantly lower than the code specified wind speeds. Some of the collapses led to worker and pedestrian injuries. Two cases involved a fatality each. In all the cases, the forensic investigators determined without difficulty that accidents were due to improper contractor practice and/or lack of engineering design. The author suggests that the accidents could have been avoided by some basic rule of thumb instructions. The relative low wind pressures that led to the collapses might also require clarifications and reevaluation of some wind design requirements for temporary installations.