Updated ASCE 7-22 standard includes first-ever criteria for tornado-resistant design

The updated ASCE/SEI 7-22 Minimum Design Loads and Associated Criteria for Buildings and Other Structures includes the first-ever criteria for tornado-resistant design.

“We’re not designing tornado shelters with ASCE 7,” said J.G. (Greg) Soules, senior principal structural engineer for CB&I and vice chair of the ASCE 7-22 Committee, in a news release. “We’re simply designing for somewhat higher wind loads in certain regions of the country.”

The standard, updated every six years, provides up-to-date and coordinated loading provisions for general structural design. It prescribes design loads for all hazards including dead, live, soil, flood, tsunami, snow, rain, atmospheric ice, seismic, wind, and fire, as well as how to evaluate load combinations.

The new update draws on new models for more accurate snow loads and includes a new multipoint seismic spectrum for certain soft-soil sites. ASCE 7-22 now requires use of digital data identified in hazard-specific geodatabases for all environmental hazards.

New York City has two very large buildings dedicated to answering the 911 calls of its five boroughs. With more than 11 million emergency calls annually, it makes perfect sense. The second of these buildings, the Public Safety Answering Center II (PSAC II) is located on a nine-acre parcel of land in the Bronx. It’s an imposing 450,000 square-foot structure—a 240-foot-wide by 240-foot-tall cube. The gleaming aluminum cube risesthe equivalent of 24 stories from behind a grassy berm, projecting the unlikely impression that it might actually be floating. Like most visually striking structures, the building has drawn as much scorn as it has admiration.