Rion Bridge (Cable Stayed Bridge) in Greece

[KAYTWO]

The following is the web link for Rion Cable Stayed Bridge.

http://enr.construction.com/news/transportation/archives/070530.asp

http://enr.construction.com/news/transportation/2007/ss/070530/070530.asp.

If you read the article, it says among the novel features of the bridge is seismically isolated. Supported solely by cables, the deck makes no direct with pylons or abutments. In other words the cables are holding the deck. Can anyone explain the design or fundamental concept for the cables holding the deck? I would appreciate your response at your earliest convenience.

Thanks.

MAK

 

[rb1957]

if the deck was attached to the pylons, and there was an earthquake, there'd be an enforced displacement on the deck which woould probably fracture it.

if the deck is isolated from the pylons, being supported by cables attched to the pylons, then the enforced displacement effects will be mitigated (by the elastic strain energy of the cables).

 

[kelowna]

rb1957 is right. The deck is 2.2 kilometers long, so it 'floats over the 4 intermediate support towers rather than bein supported on them. What that allows is that during an earthquake, the whole deck is allowed to move around, both transversally and longitudinally. Longitudinaly, the different inclination of the cables will damper the movement. Transversally, there are 4 x 3600kN elastoplastic dampers per pier which will achieve the same effect. If I remember right, the expected movements are on the range of 1.5 to 2 meters, but not completely sure.
The connection detail at the abutments is rather complex, given the magnitude of the expected movements, so there is a rotation frame and more dampers.

That is not the only seismic protection feature on the bridge, but it one of the more obvious

 

[csd72]

I imagine the drape of the cables from the center of the tower to the side of the deck acts like bicycle spokes providing some lateral resistance to minimise drift.

Otherwise you would just get a pendulum effect.

 

[kelowna]

"Otherwise you would just get a pendulum effect"

Hence the lateral dampers