Thursday, December 10, 2009

Mexico's Bridges: Puente sobre el Río (2)

Another view of a four span steel girder bridge on stone masonry pierwalls on Route 115 in the State of Colima. I've seen the use of stone bridge supports in India and other places where economics require the minimum use of concrete and the maximum use of filler material.

It looks like this dry river bed is periodically flooded (note the debris collecting against the side of the pier). Perhaps cutwaters could be designed at the upstream end of the piers to deflect the water and debris downstream.

I wonder how this bridge would perform during a large earthquake? The pierwalls are very short and stiff and would attract large forces, and they may not have much reinforcements. Still, the bridge bearings may fail first, lowering the forces on the bridge, and the resulting displacement may not be large enough to cause unseating. Probably flooding is a bigger hazard. My impression is that the engineers did a good job of building the girders above the 100 year (500 year?) flood.

I like the deck overhangs that look like they were formed with thin strips of wood. I also like the bright red color of the girders and the bright yellow of the railing. That reminds me of the Accelerated Bridge Construction blog where he shows a video of how great New Jersey barrier is at keeping vehicles on the road. I haven't seen much New Jersey barrier in Mexico.

The steel girders look well designed with plenty of vertical stiffeners and cross-bracing. I don't see any signs of fatigue or any maintenance problems, but the bridge looks fairly new.
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Mexico's Bridges: Puente sobre el Rio (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

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