How can you ensure a caisson foundation is installed correctly?

1 Choose the right type of caisson

There are different types of caisson foundations, such as end-bearing, friction, floating, open, pneumatic, and box caissons. Each type has its own advantages and disadvantages, depending on the site conditions, load requirements, and design specifications. You should consult with a geotechnical engineer to determine the best type of caisson for your project, based on the soil properties, water table, depth, diameter, and spacing of the shafts.

2 Prepare the site and equipment

Before you start drilling the shafts, you need to prepare the site and the equipment for the caisson installation. You should clear the site of any debris, vegetation, utilities, or obstructions that might interfere with the drilling process. You should also check the equipment, such as the drill rig, the auger, the casing, the tremie pipe, the concrete pump, and the crane, for any defects or malfunctions. You should also conduct a test drill to verify the soil conditions and the depth of the bedrock or bearing stratum.

3 Follow the drilling and concreting procedures

Once you are ready to install the caissons, you should follow the drilling and concreting procedures carefully. You should drill the shafts to the required depth and diameter, while maintaining verticality and alignment. You should also clean the bottom of the shafts of any loose soil or water, using a bailing bucket or a compressed air jet. You should then lower the casing and the reinforcement cage into the shafts, and secure them in place. You should then pour the concrete into the shafts, using a tremie pipe to prevent segregation and contamination. You should also monitor the concrete level, slump, and temperature during the concreting process.

4 Inspect and test the caissons

After the concrete has cured, you should inspect and test the caissons to ensure their quality and integrity. You should check the caissons for any cracks, defects, or deviations from the design specifications. You should also perform load tests, such as static, dynamic, or pile integrity tests, to verify the load-bearing capacity and settlement of the caissons. You should also measure the deflection, rotation, and vibration of the caissons under different load conditions.

5 Connect the caissons to the superstructure

The final step is to connect the caissons to the superstructure, such as the bridge deck, the dam wall, or the pier column. You should use appropriate connectors, such as bolts, anchors, or dowels, to ensure a strong and durable connection. You should also apply a protective coating or a waterproof membrane to the caissons to prevent corrosion, erosion, or frost damage. You should also maintain and inspect the caissons regularly to detect any signs of deterioration or distress.