TACOMA, Wash. -- The Washington Toll Bridge authority today proceeded with plans to rebuild the four-month-old $6,400,000 Tacoma Narrows suspension bridge, the remains of which were lying in the mud in the bottom of Puget Sound.
The bridge, third longest suspension span in the world, was whipped to pieces Thursday in a 35-mile an hour wind. It linked the Pacific northwest's three major defense units -- Fort Lewis and McChord field near Tacoma, and the Puget Sound navy yard at Bremerton. Hastily reconditioned ferries were put into service today between Point Defiance and Gig harbor.
While bridge experts argued about what caused the span to disintegrate, engineers at the University of Washington tinkered with a $14,500 model to eliminate the "bugs" from the new one.
Charles E. Andrew, former assistant chief engineer on the San Francisco Oakland bay bridge, who built the Tacoma Narrows span, said he originally had planned for open truss construction, which would offer less wind resistance. Another engineer, he said, had substituted flat girders. Another theory was that the wind against the side of the structure had caused it to vibrate as a paper vibrates when the edge is blown. Still another suggestion was that the bridge had collapsed under harmonic motion set up by the wind.
Whatever it was, the bridge began to sway like a porch swing Thursday. Two trucks and an automobile were plunged into the sound when the bridge gave way. The lone casualty was a cocker spaniel owned by Leonard Coatsworth, who jumped from his careening automobile and crawled 500 feet on his hands and knees to safety.
Patrick Henry Wilson, executive secretary of the bridge authority, said that full insurance covered would permit immediate reconstruction.