Hawaii's Interbase Interstate

Robinson, Rita; ,

Hawaii's Interbase Interstate

by Rita Robinson, Aztec Village, 3000 Aztec Rd., NE6, Albuquerque, NM 87107,

Serial Information: Civil Engineering—ASCE, 1995, Vol. 65, Issue 1, Pg. 42-45

Document Type: Feature article

Abstract:

Connecting two major military installations, Hawaii's third Interstate highway (H-3) is the largest ($1 billion) HDOT project to date as well as the longest in time (planning began in 1966) although only 15 miles long. Its centerpiece is a world-class, state-of-the-art twin-bore tunnel sandwiched between two one-mile state-of-the-art segmental viaducts. There are also three major interchanges, 16 major bridges, two cut-and-cover tunnels, relocation of Hawaii's Quarantine Station (a $20 million project in itself), all designed after studies that resulted in a highway sensitive to the fragile environment. The Trans-Koolau Tunnel is the key to routing H-3 from the leeward to windward sides of Oahu, from Honolulu up through the Halawa Valley and down the Haiku Valley to Kaneohe. Twin bores, 4,890 ft long inbound and 5,165 ft outbound, will each carry two lanes of traffic plus shoulders. Services are supplied from two buildings at each portal, one for inbound and one for the outbound bores. They house ventilation and control systems, electrical and communications equipment and water supply as well as emergency vehicles. Each concrete building steps up four levels, structurally and architecturally incorporated into the portal. The leeward twin viaducts are cast-in-place concrete segments placed by overhead steel trusses, while the windward twin viaducts are precast segmental box girders placed by a self-launching steel erection truss.

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