Compass

Sept. 12, 1993: Rebuilt I-90 bridge opens in Seattle

Compass

Construction of the bridge in 1940. (Photo: Washngton State Archives, via Wikimedia Commons)

Twenty years ago today, the rebuilt Lacey V. Murrow Bridge over Lake Washington opened in Seattle. The bridge closed one of the last major holes in the interstate highway system. Now, a person could drive all the way from Boston to Seattle without ever leaving I-90.

How did we get all the way to 1993 without a bridge across Lake Washington? Well, we had one, but it broke.

In 1940, the original bridge opened. It was two miles long and floated on more than 20 hollow concrete pontoons. It was, at the time, the largest floating structure in the world and the first floating concrete bridge. It connected Seattle and Bellevue across Lake Washington. It also carried US Route 10, late I-90, across the lake.

But in November 1990, the original bridge was destroyed in a flood. The bridge was closed at the time for repairs to resurface and widen the lanes. Water used in the hydrodemolition – a process through which high-pressure water is used to remove or destroy unwanted parts – was going to be stored temporarily in some of the pontoons that helped keep the bridge afloat. To do this the watertight pontoons were opened, but a massive storm hit over the Thanksgiving holiday weekend, filling the pontoons with rain and storm water. One pontoon sunk, pulling the others with it because they were cabled together. The bridge slowly sunk into the lake.

On Sept. 12, 1993, the new bridge reopened, re-connecting I-90 across the country.

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