New Earthquake Proof Bridge For San Francisco Bay
San Francisco Bay will soon house the largest self-anchored suspension bridge ever built. It will be designed to be able to sway when an earthquake of magnitude 6.7 or greater strikes in the future. Being constructed parallel to the already existing bridge, the new bridge will have concrete towers rising 160m above the mean sea level. These will hold the cables at the top and the other end of cables will be fixed to the road on either side of the bay without being anchored to the land.
![[IMG]](proxy.php?image=http%3A%2F%2Fwww.crazyengineers.com%2Fwp-content%2Fuploads%2F2011%2F11%2Fsan-fransisco-bridge2.jpg&hash=957a0e7465f749d73f8bafd778049ad6)
A major earthquake of magnitude 6.7 or greater is expected to strike the area within 30 years. The old bridge is already giving away after all the quakes it has faced. So before the big one strikes, this new bridge has to be ready and the traffic must be transferred to this new one. And the milestone in this project is not the completion time but the time when it’ll start carrying the traffic.
The bridge, which has to carry 2,80,000 cars a day when it is open to the public, will be finished by 2013. This bridge being a “life line†structure cannot be rushed to completion. This structure will be allowed to sway up to one meter in the sides and still not collapse and must be capable of serving the emergency vehicles that have to cross the bay after a quake.
![[IMG]](proxy.php?image=http%3A%2F%2Fwww.crazyengineers.com%2Fwp-content%2Fuploads%2F2011%2F11%2Fsan-fransisco-bridge.jpg&hash=35f37f62c5f0f469963bd4f31c075bb3)
A look at the pictorial representation of the bridge will show that there is a tall tower, actually made of four smaller concrete columns that are connected to each other by the use of shear beams. The shear beams are the relatively weak steel components that will break if the towers move. The concrete towers have their foundation drilled into the bedrock.
There are two roadways that are held by the cables but not attached to the towers. So the tower and the roads will be capable of moving when the Quake strikes. This will send data regarding the sway to the motion sensors which will transfer the data via the radio and let the officials know the extent of damage and the location. This will enable quicker and appropriate repair plans.
Source: #-Link-Snipped-#
A major earthquake of magnitude 6.7 or greater is expected to strike the area within 30 years. The old bridge is already giving away after all the quakes it has faced. So before the big one strikes, this new bridge has to be ready and the traffic must be transferred to this new one. And the milestone in this project is not the completion time but the time when it’ll start carrying the traffic.
The bridge, which has to carry 2,80,000 cars a day when it is open to the public, will be finished by 2013. This bridge being a “life line†structure cannot be rushed to completion. This structure will be allowed to sway up to one meter in the sides and still not collapse and must be capable of serving the emergency vehicles that have to cross the bay after a quake.
A look at the pictorial representation of the bridge will show that there is a tall tower, actually made of four smaller concrete columns that are connected to each other by the use of shear beams. The shear beams are the relatively weak steel components that will break if the towers move. The concrete towers have their foundation drilled into the bedrock.
There are two roadways that are held by the cables but not attached to the towers. So the tower and the roads will be capable of moving when the Quake strikes. This will send data regarding the sway to the motion sensors which will transfer the data via the radio and let the officials know the extent of damage and the location. This will enable quicker and appropriate repair plans.
Source: #-Link-Snipped-#
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