July 2008 | Volume 78, Number 7

ON THE COVER: Constructed in 1927 in the California Mediterranean style, the Pasadena City Hall features a massive circular tower and dome that rise above a rectangular office edifice. But this beautiful and elegant building, which in 1980 obtained a listing the National Register of Historic Places, has also been subjected to numerous earthquakes throughout its life, including four moderate earthquakes in the past 25 years. The resulting damage from these seismic events prompted the city to seek a seismic evaluation and upgrade that included the installation of a friction pendulum base isolation system.

(Photograph by Victor Muschetto.)

Features

Normal but Not Ordinary

By N. Dillon Beck, P.E., and Daniel R. Shiosaka, P.E., S.E., M.ASCE

The most obvious solution to designing a highway overpass that crosses a roadway and canal on a skew would have been long, curved steel girders. But the engineers working on the last leg of a major highway near Phoenix instead designed a creative concrete crossing that uses inverted T-shaped saddles to keep the substructure normal to the obstacles while the superstructure maintains its alignment. The $2 million saved by the client was then reinvested in widening the bridge.

Old Above, New Below

By Jason T. Swartz, P.E., M.ASCE, Mark F. Cline, P.E., M.ASCE, and James G. McKelvey, P.E., M.ASCE

In the 1990s, the elaborate and critically important wastewater collection system buried deep below historic Charleston, South Carolina, was found to have experienced significant deterioration. Since then, Charleston Water System has moved quickly to upgrade its deep tunnel sewer system, overcoming challenges related to seismic conditions and impediments associated with underground construction in an urban area.

Towering Feat

By Dennis C.K. Poon, P.E., M.ASCE, Ling-en Hsiao, Ph.D., Steve Zuo, P.E., and Yi Zhu

Tower 2, a recent addition to Plaza 66, in Shanghai, China, posed a number of engineering challenges, among them determining solutions for poor foundation conditions in an area that sees seismic activity and typhoons and constructing a complex steel roof lantern with two-way slopes. Because the tower is linked by a bridge to a sister structure recently completed at the site, differential settlement also was a significant issue.

A Saving Isolation

By James Guthrie, S.E., Stephen Marusich, S.E, and Geoff Bomba, P.E.

Over the past eight decades, the Pasadena City Hall has survived numerous earthquakes and suffered moderate damage. But a recent seismic upgrade and major rehabilitation should protect and preserve the structure well into the 21st century.

Arizona Public Services and Abengoa Solar

Civil Engineering News
New home for American Jewish history museum • Tunnel uncovered • Subway station expanded • International infrastructure spending • Stream revitalized • Solar power in Arizona • Wetlands restore river • News Briefs

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