John M. Hanson, who, as president, helped guide the growth of Wiss, Janney, Elstner Associates Inc. into an industry-leading forensics and failures engineer and who led probes into high-profile collapses of the Kansas City Hyatt hotel  walkway in 1981 and the New York State Thruway Schoharie Creek Bridge in 1987, died on May 26 in Green Valley, Ariz., at 84.

The firm did not release the cause of death.

Hanson, a PhD structural engineer who joined Northbrook, Ill.-based WJE in 1972, was its first non-founder president, from 1979 to 1992.

The firm’s probe of the Hyatt disaster, which killed 114 guests, pointed to changed design parameters, which overloaded walkway connectors, and poor communication.

"If you named the major structural failures that occurred in [the U.S.] in the last 10 years, we would have been involved in [investigating] 90% or more,`` Hanson told the Chicago Tribune in 1985. He told ENR that most catastrophes are “blunders caused by human-related problems, gaps in the process” (ENR 2/19/87 p. 40).

Hanson also propelled WJE’s employee buyout from construction materials maker USG Corp. in 1989.

The engineer ranks at No. 119 on ENR’s Top 500 Design firms list, with $127.6 million in 2016 revenue.

Hanson later joined North Carolina State University’s engineering faculty, but remained a WJE director until 2014. He also was president of the American Concrete Institute and of the International Association for Bridge and Structural Engineering’s executive committee.