Saturday, June 16, 2012
Rio Antirio Bridge-Megastructures
Rio Antirio Bridge. Megastructures - Impossible Bridge.
The water is too deep and the soil is too soft and the earthquake fault line cut through the middle. How do you design the bridge to overcome the nature if the worst ??
There are four types of bridge :
Beam Bridge, Arch Bridge, Suspension Bridge, Cable Stayed Bridge.
Overseas Highway / Beam Bridge. Movie : True Lies.
1.Beam Bridge :
The design of the beam bridge couldn't work, because the flat road span must be supported from
the below, probably every 100 meters has the pier that would block the ships traffic.
2. Arch Bridge :
It is too big to build.
3. Suspension Bridge :
The main cable of suspension bridge is too expensive, Greece can not afford it.
4. Cable Stayed Bridge :
In this design, there is no expensive main cable, instead the small cables hang directly to
the tower.
Because there is no sturdy base, using metal cylinders to create the base. As the earthquake this design should hold the soil firmly. Avoid the soil liquefaction.
Metal cylinders to build the base.
Due to the soil is soft, they use the anchors made of the concrete slag. The crew sails the barge to the position, lower the anchor and pull the chains tied.
The pier need to be rested on the perfect flat surface.
Gravel. How to smooth the gravel under water.
Using the guided tube to pour the gravel.
Sonar scan shows the gravel level.
The foundations were built on shore.
Pour the concrete into the reinforcement steel. But the crew just can not pour it on, due to the air bubble.
The workers use the vibration deep into the concrete to compact it.
Too heavy to lift. So engineers design the colossal structure incorporates air compartments that allow it to float.
The tower really height was never visible.
The tower was tugged to the position.
Sink the tower to the foundation.
The pier faces the dilemma. The tower needs to be strong to withstand the earthquake, but the more structure weight, the more impact by the earthquake.
To reduce the mass, the pier's shell is hollow.
Engineers go down to the pier to check.
The bottom of the pier.
To help the tower survive the earthquake, engineers come up with other design. The tower doesn't anchor to the seabed in any way. It simply rests on the top of three meter thick gravel. It means, in the case of earthquake, the tower would slide on the top of gravel and the shaking would not be transmitted to other parts of the bridge. Engineers calculate that the tower would be able to slide nearly 2 meters without compromise the bridge integrity.
Burj Al Arab. The Dubai hotel used the same way to build the foundation.
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