San Francisco is sitting on a “tectonic time bomb”
– Two major earthquakes that destroyed the city (1906, 1989)
Trans-America Pyramid
– Was the tallest skyscraper in the city
– Use: a commercial building (office workers)
– The design of the building to strengthen structure
– Steel skeleton (flexibility)
– Low centre of gravity (stability)
– Wide base, narrow top
– Pyramid shape
– Reiforced tress at the bottom
– Deep foundation of concrete (more stability)
– Additional features (that save lives)
– Seismic switch (sense the shaking and stop elevator)
Golden Gate Bridge
– Foundation deep enough to reach bedrock (stability)
– 2 towers that help with flexibility
– Concrete blocks/anchors on either side of the bridge stability)
– Steel cables that are connected to the anchors
– Each cable is made up of separate/ a bundle of steel wires (strength)
Oakland Bay bridge
– Features:
– Cables made of separate steel wires (swing freely
– Central tower made up of four pylons.
– Beams that crumple to absorb/disperse the force of the earthquake
– Roadway is made up of several pieces
– Hydraulic joints the provides flexibility and dispersement of force
Mission Bay
– Muddy land
– Features
– Very long foundation piles so it hits bedrock (stability)
– Concrete caps placed on top of piles to increase surface area
– Concrete beams
– Concrete matts
Central Subways Tunnels
– Features
– Tunnel made in segments for flexibility
– Steel mesh
– Tunnels made of concrete (strength)
– Lined with rubber (flexibility)
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