Concrete Footing Problems

Is it possible to shutter the trenches so that a casting can be made regardless of the shape of the surrounding soil?

If you are down to stable ground and as suggested you shutter and maybe even line the shuttering, if you want, it should be alright as long as you allow for joining and it isn't a ring beam for a multi story. Are you sure you do not have a ground water problem as all this could get expensive unless your running up against contract penalties.

I would pump most of the water out and pour it with a little thicker mix than usual. Any extra water will help the concrete cure.

Ever seen the pile of concrete where a driver has washed out his truck a few days later? It is hard as a rock and nearly imposible to break with a sledge hammer because it was soaked with water and allowed to cure wet.

Thanks for the help! Yes I have seen a few truck piles, I drove a mixer for ten years, and I know the water is not a problem in itself, we have poured many bridge caissons, and after the hole is bored, in a "dry" wash bed, the hole fills up with water almost to the surface. They just pump the concrete starting at the bottom, and all the water pours out the top. Our problem is the rain has been so heavy, it brings a lot of dirt in the footings with it, covering the rebar with sand and mud-NOT GOOD. Our inspectors want to see dry footings, dry clean rebar, 3 inches of space rebar to dirt...etc. I wanted to clean a couple hundred feet, tie up the steel, and pour just that section, then do the same the next day, and so-on.

Thats quite good! Hope you r out of hassles. How about preventing trenches from runoff by raising shutters above ground? This may arrest entry of debris and dirt along with water.

The answer to whether you can pour a section at a time is a qualified yes. Qualified because you have a number of consequences in doing so. No matter how well you "tie" the joint between pours, you will have a joint which will transmit building movement differently than if it were a monlithic pour.

Ultimately, this is a question for your structural engineer. I wouldn't do anything without a consultation with him or her. I imagine the inspectors will insist on it anyway, and will want a signed and sealed change order authorizing your segmental pour.

Additional concerns that come to mind is that with the continuing rain, your exposed soil under the footings may be losing compaction. Again, consult with your structural engineer to determine if his calculations for soil bearing capacity would allow for this.

Keep us posted with your progress. We'd be interested in the results.

If there is a potential for water infiltration into the foundation excavation, immediately after the footing is dug to grade (you will have to over-excavate to allow for this) , place about 6 to 8 inches of no.2 crushed stone (1/2" to 2" max. particle size) on the bottom and compact with a hand guided compactor. The stone must be 100% the product of crushing ledge rock at a quarry and have 100% fractured faces to be effective. If the excavation has already gotten wet and there is mud at the bottom, first remove the mud by hand shovel or with a toothless backhoe bucket, going down to firm in-situ soils. Then back fill with the stone as described above. This will harden up the excavation bottom, make it possible to work there without churning up mud, allow uniform bearing on firm soils and allow drainage. The rebar can then be placed on chairs supported on the crushed stone. To dewater the excavation, a sump can be dug outside the footing neat lines and a pump thrown in. A couple inches of stone should be placed on the bottom of the sump. A five gallon bucket with holes drilled in the sides and stone placed around the outside (to keep sandy or silty soils from coming in) makes a good sump. Place the bucket on the stone and then put in the pump or suction hose. As far as whether the strip footing can be poured in sections, that is up to the design engineer. A grade beam will have to be built as designed, but it may be possible to dowel sections of a strip footing together, in accordance with a method approved by the design engineer.

DA Sanford PE

I've never heard of a shutter except on a window. I'd dig a bleeder trenches at a few places around the footing. Make them small. If you read your specs it will probably require you to do this sort of thing.

"Shuttering" you may read as formwork.

Watch for excessive mud and deterioration of your trenches. I have had rebar removed and trenches cleaned prior to placement when we had water in beam trenches.

Yes. You can limit the length of footing cast during each day. The footing joint and rebar splice is typically a standard ACI specification and/or a CRSI detail. I would send an RFI to the engineer to provide a detail for a rebar splice in a footing joint. I would also ask that the engineer identify areas that the footing should not be spliced.

Typically, we leave it up to the Contractor's discretion where he puts the joints and spliced rebar, as long as they are not in areas we identify as critical.

Why don't you just pitch the excavated soil away from the trench? Then clear plastic sheeting hanging on 1x2 upside down "V" frames with a crosspole will keep the rain out of the hole and drain onto the previously pitched soil. Clear plastic will allow inspection. Precut all the framing, put it together with a nail gun. 100 ft rolls of plastic, roll it out and lay it over the frames. Annoying to do it but it certainly sounds faster than what you have been doing and it doesn't require disturbing the actual job in place. Nothing more demorilizing than doing a job over and over.

I thank you all again for your ideas. So actually, we could have poured it in sections, which was my main question, we'd be done by now in that case. I am not the concrete foreman, yet, he almost walked off today, but by darn we're going to pour it all at once come hell or high.... no more water. We have great compaction, jumping jack in all the footings, and that's the only thing that really saved us, it would have been a quagmire

you could always pour out the footing when you have it all cleared of mud and debris, and the steel is cleaned, and not bother with the flatwork during that pour, do that later. You are only talking about pouring out about 31 truck loads. Though i would be concerned about the underlying foundation being too wet. You can also pour concrete through water, if the contractor has sufficient qualifications and experience, though even then there is again concern about the foundation material underlying the pour. Keep in mind the footing is not so much a simple supported beam and a method of transferring and distributing the supported load into the foundation materials.