Wind Load History: ANSI A58.1-1972 to ASCE 7-05

Abstract

The first consensus wind load design criteria were published as ANSI A58.1-1972 by the American National Standard Institute (ANSI) in 1972. This document delineated wind load criteria based on probabilistically determined wind speed and tabulated forms of design load parameters. Since then, the wind load criteria have gone through major changes as revisions of the standard were made in ANSI A58.1-1982, ASCE 7-88, ASCE 7-93, ASCE 7-95, ASCE 7-98, ASCE 7-02 and ASCE 7-05. Major changes occurred in the wind load criteria in ANSI A 58.1-1982 and in ASCE 7-95. The most significant change is the reference wind speed, which changed from fastest-mile to a 3-second gust. Each revision made changes and adjustments in several different factors including the importance factor, terrain factor, directionality factor, gust effect factor and the pressure/force coefficients. This paper outlines only the significant changes in the wind load criteria as they have evolved over the last three decades.