Page 265 - Forensic Structural Engineering Handbook

DESIGN ERRORS, CONSTRUCTION DEFECTS, AND PROJECT MISCOMMUNICATION 8.5

FIGURE 8.3 Hanger assembly: bending and prying under lateral force.

more water to accumulate, which started the vicious cycle of ponding. A structural analysis
of the full roof structure, including the deflections of the main trusses and portals, would have
indicated that up to 9 in of water could collect at the drains, overloading the structural system.
These nonlinear effects do not appear to have been considered in the design.
The final analysis revealed that the collapse of the Kemper Arena could not be explained
by a single cause and that intensity of rain downpour, drain deficiencies, wind effects, fatigue
of bolts, and lack of redundancy all contributed to the collapse; these were clearly design defi-
ciencies. Media reports of a single bolt collapsing the arena masked the complexity and sub-
tlety of the effects that led to this collapse. The Kemper Arena was rebuilt with a slightly
raised roof at the center, more drains, modified ductile hangers, and deeper joists.

The Kansas City Hyatt Regency Walkway Collapse
When completed in July 1980, the Hyatt Regency complex consisted of a 40-story rein-
forced concrete tower housing the guest rooms at the north end, a central atrium, and a four-
story “function block” containing all the service areas at the south end. Three walkways,
suspended from the atrium roof trusses, connected the tower to the function block through
the 120-ft atrium span: two, one above the other, at the second- and fourth-floor levels on
the west side of the atrium, and one at the third-floor level on the east side.
On the evening of July 17, 1981, the atrium and walkways were filled with over 1,600
people for a tea dance competition. At 7:05 p.m., a loud crack echoed throughout the build-
ing and the second- and fourth-floor walkways crashed to the ground killing 114 people and
injuring over 200 others. It was the worst structural failure in the history of the United
States, and one with more than a single lesson that should be learnt. Within hours, theories