Abstract

This paper explores the design profession’s evolving understanding of lateral design. It shows how the United States building codes’ handling of seismic and wind forces has changed over time, often in response to extreme events or technological developments. Prior to the early 1900s most buildings were designed without an explicitly defined lateral force resisting system. Up to that time period earthquakes and strong wind events produced little in the way of code requirements to address lateral forces. It was the advent of steel and high-rise construction in the late 19th Century that triggered a need to consider lateral loads. During the early 20th Century little consensus existed regarding the lateral forces that needed to be resisted. Wind loading provisions began appearing in the codes of large cities in the early 1900s, but it would not be until the 1930s that seismic provisions started to be codified, and then only in California. Throughout the 20th Century significant lateral events have continued to expose vulnerabilities that have been subsequently addressed with changes in construction detailing and code restrictions. In the mid-1900s regional building codes developed, focusing on the lateral hazards present in their locality. By 2000 these regional codes were replaced by a national code, and lateral design has now started to shift from prescriptive requirements towards performance-based design. This paper will help structural engineers better understand the historic building stock by exploring how lateral design has evolved in the US over the last hundred years.