Cal Memorial Stadium, nearly 90 years old, was built directly on top of the Hayward Fault line. In preparation for a planned $200 million retrofit, the project consisted of temporary safety measures prior to the start of the football season. The Interim Measures project consisted of (1) reinforcing the ancient concrete scoreboard towers; (2) a system of steel shores to support the existing concrete "bowl"; (3) a design-build system of egress protection; and (4), miscellaneous architectural work. This was on a very fast-track schedule.
The scoreboard pediments are reinforced with steel plate collectors and vertical stiffener channels, fished up from below and hoisted down from above, and with new concrete footings and grade beams. The shoring system consists primarily of steel tube shapes, installed out of plumb and designed to right themselves in reaction to an outward thrust of the stadium's bowl. These articulating posts bear on new footings and grade beams, and concrete "catch walls" are additionally installed to support and cushion a failing beam. The egress protection system consists of overhead steel and chain link fence fabric, designed to protect persons below from spalling concrete.
In addition, Overaa was awarded a second emergency contract to provide steel light pole supports and light poles. The light pole supports are 20' - 14"x14" tubes, picked from an adjacent site, and hoisted down through holes in Cal's Press Box, with 32" light pole bases of 2" steel plate. The project also includes extensions of the Press Box decks to provide for egress clearances, as well as new egress stairs down to field level and other small projects.