retaining pouring 1

[StewardMM]

there is a plan to construct a 100m long,3m high concrete cantilever retaining wall, does this necessarily be a monolithic pouring, or its ok to have it segmental , by how many meters?

 

[hokie66]

Sure, it can be cast in sections. In fact, I doubt that a wall that long has ever been cast in one placement.

 

[crcivil]

One of your objectives for this job will be saving costs in formwork, so pouring your wall in sections is actually a good idea for this purpose. I would suggest to habilitate for a 25 m. segment of wall and make a total of four pours using the same formwork, if the schedule allows you of course. Good luck and best regards.

 

[StewardMM]

Thank you crcivil. may i ask what is the basis of the 25m segment?

 

[crcivil]

It is just an arbitrary length of wall aiming at having crew continuity. The longer the segment the faster you will finish but then your formwork costs will go up. The shorter the section the more you will save in formork costs but the longer it will take for you to finish due, among other things, to idle time and work discontinuity between construction crews. You will want to balance your production lines (rebar, formwork, pouring, stripping, curing)in such a way that they are more all less paralell and do not intersect with each other; continuity is the aim. Hope this helps StewardMM.

 

[crcivil]

Another issue is concerning the use you will make of your formwork. Fabricating for one 25 m. long section and then reusing it four times sounds like a reasonable think to do for practical matters. Then you can think of SHOTCRETING your wall and saving half of the formwork costs by formworking only the back of the element, speeding up the process at the same time. Regards.

 

[cvg]

casting a large structure in sections helps to reduce stress in the concrete caused by shrinkage. we often require pouring in a checkerboard pattern so that shrinkage cracks can be reduced or eliminated, especially for water retaining structures such as long box culverts and concrete lining for channels as well as large areas of structural concrete pavement such as airport aprons.