Wind Loading—Practicing Engineers and the Code

There is widespread concern among practicing engineers that the clarity and usability of the building codes have radically diminished as the size and complexity of the codes have increased. One tool for assessing the ability of practicing engineers to consistently and reliably implement the code is the use of Trial Design Problems. The Trial Design Problem process consists of (a) developing a common engineering problem, (b) enlisting practicing engineers to complete the engineering problem using the code, (c) evaluating the engineering solutions submitted by practicing engineers, and (d) conveying the results of the problems to the engineering community and code development committees. The Design Practices Committee of the Structural Engineering Institute recently completed several Trial Design Problems related to wind loading per the ASCE 7-05 code and the new Alternate All Heights Method of the 2009 IBC. The quantitative analysis of the Trial Design Problem solutions indicated serious concerns with the ability of practicing engineers to reliably and efficiently implement several provisions of the ASCE 7-05 wind procedures including: (1) Using ASCE 7-05, only 1/2 of the practicing engineers properly accounted for the internal pressures. (2) Using ASCE 7-05, only 1/3 of the practicing engineers properly accounted for torsion or end zone pressures. (3) The new Alternate All Heights Method in the 2009 IBC yielded more reliable and accurate results in less than 1/2 the time as compared to ASCE 7-05 Method 2. Considering the Trial Design Problem results, a follow up study was performed to evaluate the committee structure of the ASCE 7 wind committee as compared with other ASCE 7 committees. The study indicates a clear connection between the usability of the code provisions and the number of practicing engineers on code committees.