Plastic Highway Bridges

Plecnik, Joseph; Deshpande, Rahoul; Henriques, Oscar; ,

Plastic Highway Bridges

by Joseph Plecnik, Prof.; Civil Engrg. Dept., California State Univ., Long Beach, CA,
Rahoul Deshpande, Grad. Res. Asst.; California State Univ., Long Beach, CA,
Oscar Henriques, Grad. Res. Asst.; California State Univ., Long Beach, CA,

Serial Information: Civil Engineering—ASCE, 1991, Vol. 61, Issue 7, Pg. 64-65

Document Type: Feature article

Abstract:

For highway bridges, composites are most effective in cables and decks. Researchers have developed and tested cables and deck sections for strength and fatigue resistance. Link-type cables provide continuity between the end anchorage and the main load-carrying part of the cable, transferring loads to the support via bearing stresses and eliminating the shear stresses of potted-type anchorages. The links are manufactured by the racetrack method and are easily adaptable for mass production. The end eyes are reinforced with Kevlar and graphite to reduce stress concentrations. Stress calculations showed the static strength of the cables varied between 239 and 445 ksi depending on configuration. The specimens were fatigue tested at a frequency of 2 Hz. Twelve cables survived at least 200,000 cycles; four survived over 2 million cycles. A composite deck's primary advantages are its lighter weight, greater corrosion resistance and ability to be shop fabricated in modular units that may be rapidly installed without shoring or formwork. Composite decks will probably have a deck cross section consisting of multiple X's. This deck is typically 70-80% lighter than a conventional concrete deck and reduces the total deck load of a conventional bridge's superstructure by up to 54%. Modular composite deck construction will result in large shop- or field-fabricated sections quickly assembled at the bridge site. We also tested decks under static and fatigue loadings.

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