THE WORST STRUCTURAL DISASTER IN U.S. HISTORY Refs: (1) Levy and Salvadori, “Why Buildings Fall Down”, Norton, 1992 (2) Petroski, “To Engineer is Human”, Vintage, 1992 (3) (Fleddermann, p. 70) (4) http://ethics.tamu.edu/ethics/hyatt/hyatt1.htm) Bring: rope * KC Missouri Hyatt Regency: Opened July 1980. Poshest hotel in KC. Owned by Donald Hall (Hallmark Cards). 750 rooms, fine dining, the KC location for posh events * Hotel in 3 sections: (1) Room tower (2) Function room block (3) Atrium connection 3 open “skyways” (floors 2, 3, 4) traversed the atrium connecting the function rooms with the guest room tower. Kansas City Hyatt Regency 7:05 PM, Friday July 17, 1981 114 dead, 200 injured Source: http://lowery.tamu.edu/ethics Engineering Ethics

* What do you think happened? * July 17: Ballroom dance. 1600 people dancing to well-known local band * People on all 3 balconies tapping their feet and swaying to the music * A loud sound. Fourth-floor skyway started to fall, taking second-floor skyway with it. Concrete and steel crashed to the ground on the crowd gathered near the bar and sending shards of concrete flying up to 100 ft. * What do you think happened? * Suspects were: (1) frequency of foot tapping matched resonance of skyway, (2) poor materials or poor workmanship * Answer: Design/build mismatch. A change was made during construction (approved by the designers) which caused the fatal crash Source: Levi & Salvadori, “Why Buildings Fall Down”

Skyway construction * Walkways are 120 ft long, in four 30 ft sections ROOF TRUSS GUEST TOWER FUNCTION BLOCK 4TH FLOOR SKYWAY HANGER ROD * Walkways are 120 ft long, in four 30 ft sections * Sections are supported by transverse box beams * Box beams are fixed to hanger rods anchored to roof truss * Do a “2 person on a rope” demo with 2 volunteers 2ND FLOOR SKYWAY BOX BEAM Adapted from: Levi & Salvadori, “Why Buildings Fall Down” Engineering Ethics

* During construction, the design changed from one continuous rod to two rods. * Original design called for a nut and washer 15 ft. up the 45 ft. hanger rod. Difficult to fabricate (thread whole rod or make threaded section larger diameter than the rest). Suggestion to change to a two rod design must have seemed reasonable. * Other solutions: Use a sleeve nut to couple two rods. Use the box beam as the “sleeve”. Easy to see in hindsight! Source: Levi & Salvadori, “Why Buildings Fall Down”

AS DESIGNED AS BUILT 4th FLOOR 2nd FLOOR 4th FLOOR 2nd FLOOR

* Turns out that original design would not have met code. * Walkway #3 taken down. Now a single, second floor walkway supported by stout posts * Turns out that original design would not have met code. * Design engineering firm sued. Several designers lost their state licenses. Levi & Salvadori, “Why Buildings Fall Down” Source: http://lowery.tamu.edu/ethics

Ethical Issues: Hyatt Regency Case Who is ultimately responsible for checking the safety of final designs as depicted in shop drawings? In terms of meeting building codes, what are the responsibilities of the engineer? The fabricator? The owner? What measures can professional societies take to ensure catastrophes like the Hyatt Regency Walkways Collapse do not occur? (http://ethics.tamu.edu/ethics/hyatt/hyatt1.htm) Engineering Ethics

Curent Configuration Engineering Ethics http://www.sheratonkansascityhotel.com/gallery Engineering Ethics