EVENT DETAIL

The AASHTO LRFD Bridge Design Specifications (AASHTO LRFD) was written in the early 1990’s with wind load provisions that were derived from the American Society of Civil Engineering (ASCE) Minimum Design Loads for Buildings and Other Structures/ASCE 7-88 and adapted for bridge design. These provisions were based on the fastest-mile measure of wind speed which was used by the National Weather Service. However, since then, the National Weather Service has changed to the 3-second-gust measure of wind speed and recent editions of ASCE 7 have also been based on the 3-second gust. The revisions were based on years of ongoing research of wind loads on structures and included new wind speed maps based on the 3-second gust.
 
The current method in the AASHTO LRFD does not provide consistent reliability for different regions and locations. Also, there have been some reports of typical bridges experiencing excessive motions and vibrations due to wind loads during construction. This presentation discusses the revisions to AASHTO LRFD wind load provisions that were recently adopted by AASHTO and introduces the provisions proposed to identify bridges prone to excessive motions and vibrations due to wind loads during construction.