Caisson

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Caisson

What is Caisson?

Caisson, A deep foundation element created by drilling large diameter holes and filling with concrete to support heavy structural loads

Description

A caisson is a deep foundation element created by drilling large-diameter holes into the ground and filling them with concrete, often including reinforcing steel, to transfer heavy structural loads to competent bearing materials at depth. These robust foundation systems enable construction of tall buildings, bridges, and other heavy structures on sites where surface soils cannot provide adequate bearing capacity or where deep foundations are required for other engineering reasons.

Purpose includes supporting heavy structural loads, reaching competent bearing materials, providing lateral stability, and enabling construction on challenging sites. Quality caisson foundations are essential for major construction projects requiring deep foundation support.

Construction methods include drilled shaft caissons for most applications, bored caissons for specific conditions, and excavated caissons for special situations. Each method offers different advantages for specific soil conditions and project requirements.

FAQs

  • What’s the difference between caissons and piles?

    Caissons are typically larger in diameter and drilled, while piles are usually smaller and driven; both provide deep foundation support.

  • How deep can caissons go?

    They can extend 200+ feet deep depending on soil conditions and the depth of the bearing layer.

  • What determines caisson capacity?

    Capacity depends on soil properties, caisson diameter and depth, concrete strength, and load transfer mechanisms, requiring engineering analysis.

  • Can caissons be installed in any soil?

    They can be installed in most soil conditions, though flowing sand or artesian water may require special techniques.

  • How are caissons tested?

    Through load tests to verify capacity and integrity tests to confirm construction quality.

  • Do caissons need reinforcement?

    Often yes, especially where lateral loads or tension forces are present; reinforcement design depends on loading conditions.

  • How much do caissons cost?

    They are more expensive than shallow foundations but necessary for heavy loads or poor soils; costs vary by size and depth.

Fun Fact

Fun Fact: The first modern caissons were used for bridge construction in the 1850s, enabling construction of major river crossings.

Links

CSI Code

31 63 13

NAHB Code

330