earthstory reblogged
Why seismic design is important, a three decade remembrance.
These images are of the formerly two-deck Cypress Structure on the route of Interstate 880, the Nimitz Freeway in Oakland, California after the 1989 Loma Prieta Earthquake. When we arrived in the SF Bay Area in the early 1960s, the highway was known as State Route 17 and there was some amount of scandal over alleged shortcuts taken in the construction. Not enough rebar, not enough portland cement in the concrete and more. It didn’t help that the pilings were set into bay mud that wasn’t particularly stable. Even with normal traffic, the structure shook and vibrated badly and I hated driving on it.
So with just 15 seconds of shaking, down it came.