Historic Yorktown: New Bridge Keeps Old Design

Abrahams, Michael J.; ,

Historic Yorktown: New Bridge Keeps Old Design

by Michael J. Abrahams, Parsons Brinckerhoff Quade & Douglas, Inc., One Penn Plaza, New York, NY 10119-0061,

Serial Information: Civil Engineering—ASCE, 1994, Vol. 64, Issue 11, Pg. 46-47

Document Type: Feature article

Abstract:

In historic Yorktown, Va., the best solution to reconstructing an obsolete 1952 bridge was to keep its unique design while widening it for '90s traffic. Like the original, the George P. Coleman Bridge had to remain invisible from the Colonial National Historical Park, and the U.S. Navy kept the 135 clearance requirement. The solution was to widen the bridge and replace the two 500 ft center-pivot swing spans, closing the bridge to traffic for only one two-week change-out period. Key economic considerations were 1) the original caissons could be reused as is and 2) the river piers could be widened at their tops. On land, additional piles will be driven so the entire piers can be widened. The new bridge is 74 ft wide with two lanes in each direction, a median divider, 2 ft shoulders on the inside lanes and 10 ft shoulders outside. The new wider truss spans and swing spans will look like the originals, as use of higher strength Grade 50 and 70 steels permit similar truss depths. Where the originals were riveted, the new trusses will be shop welded and field bolted. The existing girder approach spans--two riveted steel girders with floorbeams and stringers supporting the deck slab--will be replaced so that the roadway slab will be supported on parallel prestressed concrete girders. Decks will be regular weight concrete except on the swing spans, where lightweight concrete will be used instead of the original open grid steel decks.

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