Tacoma Narrows Bridge Photo Album

Bridge Deck

Piecing together a suspended roadway represents the represents the fifth and final phase of the new Tacoma Narrows Bridge project. The entire deck-lifting process will take four months to complete.

The mile-long roadway is made up of 46 deck sections. The deck sections that average 120-by-78 feet and weigh 450 tons will be lifted one at a time with “gantry cranes” (special lifting hoists) that straddle the cables. Each section will be attached to vertical suspender cables, and then connected to the main cables.

The first deck section will be placed in the center span location. The remaining 45 blocks will be lifted in an order that, to the casual observer, may appear almost random. That is not the case. Rather, the non-linear order of lifting sections is designed to maintain equal stresses on the bridge’s two towers. The weight of all 46 sections will pull and lower the main cables about 25 feet below its present and non-weighted profile. This stretching process will place the new bridge deck at the same level as the 1950 bridge deck.

As construction gets underway in July 2006, passersby will notice crews simultaneously building the deck out from the east and west anchorages. In the initial assembly of the sections, the deck pieces will be joined temporarily with shear lugs and bolting fixtures. When the majority of deck sections are in place and the cables near their final profile, the crews will weld the deck plates and bolt all other truss sections together, then top the surface with two inches of asphalt.

Deck lifting and assembly of all sections is scheduled to be complete by late 2006.

Click on any thumbnail for enlarged image and description.

(Last updated 08/02/06)

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