Abstract

Wind-induced natural disasters have been frequently reported as some of the most fatal and costly catastrophes. Of particular intensity was the disastrous effect on low-rise residential properties that suffered in several cases from a complete damage. The intense research efforts of the wind engineering community contributed significantly towards the development of more complex yet safer wind standards and building codes of practice. Numerous studies have been carried out focusing on the estimation of wind-induced envelope pressures using in most cases wind tunnel experimental techniques and less often field studies. A key component that has not yet been investigated adequately is the flow of wind-induced forces through the structural system and their attenuation due to dynamic and other structural aspects of light frame construction.
The field monitoring of a low-rise wood building provided valuable information related to its wind-induced structural response. The building was equipped with a state-of-the-art data acquisition system to monitor weather, pressure and force data. In addition, detailed wind tunnel tests on a scaled model and finite element analysis were used to study the wind effects in a simulated environment.
Despite the vast amount of field data that were acquired, only a limited number was qualified as stationary and considered for further interpretation. The analysis revealed a non-uniform upstream exposure which was incorporated in the wind tunnel experiments and improved the agreement between the two experimental approaches. Of particular importance were the findings related to wind-induced uplift force distribution, especially those related to the attenuation of the wind load. For this analysis, data from pressure taps and foundation load cells were considered and incorporated in the finite element analysis. A significant reduction was identified as the wind-induced load is transferred through structural and non-structural elements to the foundation level. This attenuation was evident in the field data but was not predicted by finite element analysis, indicating that wind design practices based on static analysis of structural systems will tend to conservatively estimate actual building performances. Another interesting finding was that the wind load is transferred predominantly to the two side walls whereas the end walls have a significantly smaller contribution. Last but not least, the comparisons of the findings to current wind provisions, such as ASCE 7 and NBCC, revealed that in certain cases the recommended by the standards values could underestimate the total uplift wind force.