Concrete Trench Wall Movement

[m1e9r5c6]

Hello All! This is my first post here, although I have been reading here alot before taking the plunge to ask a question.

The question I have involves a problem we are having with road crossings over a concrete trench wall. The force of vehicles crossing the trench has moved the walls inward. The task before me is to find a simple way to straighten the walls and support them adequetly to prevent this from happening again. The trench houses electrical cables (placed in trays attached to the walls) in a transformer station.

The trench is 4' wide and 3' deep with 8" thick concrete walls on either side for soil retention. The wall is supported by piles and an 8" slab bridges the trench at these locations (crossings are 20' wide). As far as I can tell, the walls were installed as 10' precast sections, and are supported by steel bracing across the trench at the joints however, the slabs seem to be bending at the mid point.

Soils are sandy below 12" of pit run gravel and 2" of crushed rock. The floor of the trench is sand.

My current plan involves digging out the back side of the wall to relieve pressure, then using hydraulic jacks to move the wall back into alignment. Support the walls at multiple points prior to back filling. Would this be feasible? Do I run the risk of wall failure while jacking?

What are your thoughts for a possible solution, keeping in mind it must be inexpensive, fast and done with limited equipment (a small back hoe and hand tools).

I look forward to hearing your thoughts.

 

[cdh61]

m1e9r5c6,

You have a few options,

1st, if you could live with the existing movements then you may be able to tie back wall to prevent further movements.

2nd, soil removal then jacking can work, but most likely the wall is already cracked if it has moved any noticeable amount. And you will then still have to have some tie back or pouring of more concrete for reinforcement.

3rd, could you add steel external bracing to aid in preventing further bending.

4th, you could add more bracing across the trenchs, just like there is now at the joints.

As for pricing, contact local contractors and ask then out to the site to discuss. Pricing will depend on site conditions and level of work. Be careful of contractors who are not versatile.

regards