Diaphragm walls are commonly used in congested areas for retention systems and permanent foundation walls. They can be installed in close proximity to existing structures with minimal loss of support to existing foundations. In addition, construction dewatering is not required, so there is no associated subsidence. Diaphragm walls are created by removing and replacing in-situ soil with a material of known characteristics. A series of deep, intersecting, rectangular trenches are excavated in the soil or rock, and are subsequently filled with material of controlled quality, which forms a structural support wall. Diaphragm walls have been used as deep groundwater barriers through, and under dams. In some applications, they are constructed with a non-reinforced plastic concrete material.

RECON was contracted to design and build a Limestone Unloading Pit (LUP) at a power plant in Ohio. Limestone loaded trains pass over the top of the LUP, supported by a 42-inch thick reinforced concrete "diaphragm wall", which is at depths of more than 50 feet below grade.

Project Features

• Excavating segments utilizing a crane and clam bucket, between temporary "guide walls" to maintain alignment
• Securing temporary metal templates on the guide wall
• Reinforcing steel cages were fabricated and carefully lowered into the panel excavation
• Placing concrete into the excavation using tremie pipes to complete the diaphragm wall panel
• Repeating this process to create the individual panels of the permanent wall of the LUP.