Caisson foundations subjected to lateral forces

This paper treats the analysis of a caisson foundation subjected to lateral loads and embedded in a multi-layered soil with special emphasis on their use in transmission line structures. The method developed which is based on the subgrade modulus concept, aside from being useful for the design of a caisson foundation for limited displacements, can be used for determining the stiffness of a given foundation. A rational method of evaluating, the foundation stiffness is very useful to the designer since he can then treat the superstructure and the foundation as an entity rather than two separate entities and can thus optimize the total cost of the structure/foundation system. Results from load tests on a prototype caisson in sand and clay, designed by this method, indicate reasonably fair correlation with those predicted by the theoretical analysis.