Foundation Specifications 0168

Sub Sections: 1 2 3 4 5 6 7 8 9 10 11 12
Pages: 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174

Our techniques apply when adding new structures: especially rock anchor, microfine cement, soil nailing, micropile installations for foundation support. We specialize in slope stabilization, anchors, permeation grouting, foundation repair and support, grouting, soil nails, rock drilling, micropile installations, and sinkholes. We use a problem-solving approach geotechnical architecture of buildings, bridges, water plants, sewage plants, tunnels, sinkholes, caisson, shoring, underpinning, agriculture, and roads construction. We are experienced in these applications: micro piles, sinkhole repair, permeation grouting, pressure grout, soil nails, chemical grouting, micropiles, compaction grout, and rock anchors. Our specialties are rock anchor, acrylamide and compaction grouting, mini piles, sinkhole repair, micropiles, acrylamide grouting, and soil nailing. We will continue to dedicate ourselves to excellence, including insurance mortgage, in our performance, in our integrity, and in our relationships with our customers. We will carefully weigh our decisions, actions, and results to make sure that we remain the most trusted name in the geotechnical contracting industry. Please visit our website http://www.rembco.com/. Add Concrete Construction URL

Slurry Displacement Piles

The concrete placement operation for a CIDH pile constructed under drilling slurry is an

operation that requires much preplanning. Before the work begins, the contract specifica-

tions require that the concrete mix design meet the trial batch requirements for compres-

sive strength concrete. These requirements are described in Section 90-9 of the Standard

Specifications. The concrete mix must contain at least 658 pounds of cement per cubic

yard. It is also important to compare the maximum aggregate size in the concrete mix

design to the bar reinforcement spacing. The bar spacing should be no less than five times

the maximum aggregate size. The Project Designer should be contacted if this is not the

case. A concrete test batch is also required to show the concrete mix design meets the

consistency requirements of the contract specifications. The concrete consistency require-

ments are to ensure that the concrete will remain fluid throughout the length of the pour.

The Engineer shall not allow the Contractor to exceed the maximum allowable water

requirement to achieve this goal. Chemical admixtures will most likely be necessary. It is

also important for the concrete mix to be properly proportioned to prevent excess bleedwater

due to the high fluidity of the concrete.

The method of concrete placement should not permit the intermingling of concrete and

drilling slurry. The contract specifications allow placement of concrete through rigid tremie

tubes, or through rigid tubes connected directly to a concrete pump. In order to prevent

intermingling of concrete and drilling slurry, the concrete placement tubes must be capped

with a watertight cap or plugged such that the concrete will not come into contact with the

drilling slurry within the concrete placement tube. The cap or plug should be designed to

release when the placement tube is charged with concrete. Charging the placement tube

with concrete shall not begin until the capped or plugged tip of the placement tube is

resting on the bottom of the drilled hole. Once the placement tube has been charged, the

pour is initiated by lifting the tip of the placement tube 6 inches above the bottom of the

drilled hole. This allows the concrete in the placement tube to force the cap or plug out of

the placement tube and discharge. Once the pour has started, it is important to place the

concrete at a high rate until the tip of the placement tube is embedded in the concrete. If

concrete placement operations slow or stop before the tip of the placement tube is embedded

in concrete, there is nothing to prevent the intrusion of drilling slurry into the placement

tube. If this happens, the likely result will be a defect at the tip of the pile. Once concrete

placement begins, the tip of the concrete placement tube shall not be raised from 6 inches

above the bottom of the drilled hole until a minimum of 10 feet of concrete has been placed

in the pile. After this level is reached, the tip of the concrete placement tube shall be

maintained a minimum of 10 feet below the rising head of concrete. The best way to verify