
May 15, 1998

WACA Award: Special Applications -- Technical

Journal staff

Projects entered in this category ran the spectrum -- from a giant retaining wall in Magnolia, to the Key Arena ice rink slab, to five miles of concrete slab and shell for a gravitational wave observatory in Richland.

The LIGO project

The LIGO project in Richland took the top spot for Special Applications -- Technical.

The observatory took the top spot in this category. The project involved building a precise measuring device housed in two 4-foot-diameter metal tubes connected at a 90-degree angle at the ends. Each tube is 2.5 miles long. To anchor the tubes, two 8-inch-thick and 14-foot-wide concrete slabs running the length of the tubes were poured. Each continuously reinforced slab had to be constructed to be within 1 inch of being perfectly flat for the entire 2.5 miles. To do this, the curvature of the Earth had to be considered.

To protect the tubes, concrete enclosures were used. The enclosures were cast in arched segments, each about 14 feet wide at the bottom, 9.5 feet tall, 10 feet long and 6 inches thick. Over 2,700 segments were cast to cover the tubes, requiring nearly 14,000 cubic yards of concrete.

Project teams

Magnolia Bridge slide repairs-retaining wall: Seattle Public Works, owner/developer; Sverdrup Engineering, structural engineer; Atkinson Construction, general contractor; Air Placed Concrete Specialists, concrete contractor; and Stoneway Concrete, concrete supplier.

The new Key Arena ice slab: Seattle Center, owner/developer; Cary Kopczynski & Co., structural engineer; PCL Construction, general and concrete contractor; NBBJ, architect; and Stoneway Concrete, concrete supplier.

Laser Interferometer Gravitational Wave Observatory: National Science Foundation, owner; Caltech, developer; Parsons, architect and engineer; Acme Materials and Construction, general and concrete contractor, and concrete supplier.