Saturday, April 3, 2010

Concrete Piers For A Concrete Bridge

Now here is something a bit different. 
Ever need some concrete piers for that backyard project? 
Well when we were in San Carlos, Sonora this winter a new bridge
 was being built to replace one that was washed out by a hurricane last fall
 providing much entertainment to the people wintering there including
 myself. Above the crew is just starting to drill a hole with the auger bit
 you see on the pile driver.

Once the auger bit gets deep enough a sleeve about 12' long 
is inserted in the hole to keep the walls from collapsing in.
 A new bit in a drum is attached to the driver to continue the bore 
and digs deeper. The rebar you see sticking up is from completed holes 
already poured.

The crew prepares the rebar cage that will go
 into the hole before the concrete is poured.
 In the background the shoot to pour the concrete is readied.

That is a deep whole, about 35'. 
The idea is to get the footing down to solid ground
 before building the abutment walls.
The bridge is right next to the Sea of Cortes so it needs to be solid.

Down it goes.

The crew drilling the piers is a sub-contractor to the general contractor 
on this job. All they do is drill pilings with this machine made in Italy 
and bought second hand. The owner is standing in the center of the
 two laborers and the driver of the machine ( not seen in this photo ) has
 worked all over the world including helping with the clean up after 9/11. 
They are a top notch crew, incredibly dedicated
 and hard working in what can be a dangerous job.

The shoot to pour the concrete is put in place.
 The concrete is poured from the bottom up to displace the water that fills the hole.

Up on top the pumper truck is sending the concrete to the shoot 
as the man in the foreground works on the test samples.

You can just barely see the hose from the pumper truck.
 The water pouring out of the sleeve is being displaced
 by the concrete pouring into the bottom of the hole.

The pour is over and the shoot is being removed.

The sleeve is removed.

After the concrete has set the rebar is cut off and the top foot or so of 
concrete is removed to remove any concrete contaminated by the water
 or dirt. Next I will show the wall being built on top of the piers.
 Remember not to try this in your back yard. 
This work is for professionals only.