Page 163 - Forensic Structural Engineering Handbook

4.12 DESIGN AND CONSTRUCTION PRACTICES

contractor (through an indemnity clause in the construction contract) and awarded the
widow and stepdaughters more than $1 million in damages.
Low bidders and “can-do” types kill people. Construction is dangerous, and builders
sometimes take undue risks in order to save time or money. The engineer may be forced to
accept the consequences of that risk under the worst circumstances. In this case, the jury
decided that the general contractor and the owner actively prevented the SER from fulfill-
ing his obligation to exercise care and diligence. The jury found the actions of the SER were
not beneath the standard of care, and the jury placed responsibility where it belonged.

Tacoma Narrows Bridge Collapse

In 1940, wind-induced oscillations destroyed the brand new Tacoma Narrows suspension
bridge. One hundred years earlier, the dangerous dynamic effects of the wind were known,
and suspension bridge design of that era included measures to counter those effects. The
engineer for the Tacoma Narrows Bridge superstructure, described as “among the highest
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authorities in suspension bridge design,” was not thought by many at the time to be neg-
ligent. This was in spite of the fact that normal competence of suspension bridge designers
of a century earlier included avoidance of this kind of failure.
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Diane Vaughan wrote about the Space Shuttle Challenger explosion. She describes
the engineers and managers of the space shuttle program as succumbing to the “normal-
ization of deviance,” the gradual acceptance of sequential minor errors and failures, accu-
mulating and culminating in a major catastrophe. The Tacoma Narrows failure may have
been an example of this phenomenon.
The advancement of the state of the art is not always forward. It is important to know
the history of the technology you are working with. Contrary to Henry Ford’s opinion, history
is not bunk.

Hyatt Regency Kansas City Walkway Collapse
A minor, “nonstructural” feature of a hotel—a walkway suspended from the roof and span-
ning a central atrium—collapsed suddenly, killing 114 and injuring a great number of people.
The detail of the connection of the walkway beam to the suspender was never designed or
completely detailed. A drawing was sent from the design engineer to the steel fabricator, but
the drawing was incomplete and ambiguous. Construction of the walkway took place with-
out complete design drawings, and without engineering review of the actual conditions.
The structural engineer of record for the building was found to be negligent. Several
important lessons can be learned from this tragedy: (1) Attention to the constructibility of
a detail is essential to good design; (2) Communication of field changes to the designer is
essential; (3) Shop drawing and change order review is important, and should not be per-
formed without the participation of an experienced practitioner; (4) The smallest detail can
cause a major problem; and (5) In practice, the consequences of an error can have a bearing
on the evaluation of negligence.

CitiCorp Building, New York
To accommodate a smaller building on the site, the high-rise CitiCorp tower was designed
and constructed with its main columns at the middle of each side, rather than at the corners.
The New York City Code, and high-rise structural engineering practices, required the
building frame to be analyzed and designed to resist winds acting perpendicular to each