Caisson

Caissons

Caisson is borrowed from French meaning box. Caissons are preferred when the load is needed to carry at the end as a foundation. In many places around Southern California such as Los Angeles, Orange and San Diego County, hillside properties need this type of foundation in combination with grade beams to support their building structures.  They are used in critical cases when houses are located on unstable soil or a hill in order to prevent the house from settlement, moving or sliding.

Caisson foundations are similar in form to pile foundations, but are installed using a different method. It is used when soil of adequate bearing strength is found below surface layers of weak materials such as fill or peat.

Caissons constructions are starts with drilling 18 to 36”diameter piles through enough soil and rock layers in order to reach the desired bedrock. In caisson construction, rebar cages are typically used to reinforce the shaft. The design of this cage is critically important to the stability of the cage and the success of the overall construction project. Then rebars are tied based on the engineering plans specifications and pull down to the drilled holes. The last effort is pouring concrete in the hole to finalize the caisson construction.

Grade beams and caissons are usually used together and in combination to be an important solution to prevent slides for residential homes on hillsides.