Design of laterally loaded piles
The ultimate lateral resistance and the working load deflections of single piles and pile groups depend of the dimensions, the strength, and flexibility of the individual piles, and on the deformation characteristics of the soil surrounding the loaded piles. Methods are presented for the determination of the ultimate lateral resistance based on the concept that the ultimate lateral resistance at relatively small penetration depths is governed by the passive lateral resistance of the soil surrounding the loaded piles, and that the ultimate lateral resistance at relatively lare penetration depths is governed by the ultimate or yield resistance of the pile section. The concept of the over-load and under-sterngth factors is introduced. The numerical values of these factors depend on the danger of loss of human lives and the economic consequences in the case of failure. Accordingly, the factors have been so chosen that the probability of failure is less than a certain quantity. Methods for the calculation of lateral deflections at working loads are presented. These methods are based on the concept of a coefficient of subgrade reaction. I has been assumed that the coefficient of subgrade reaction increase linearly with depth in the case of cohesionless soils and that it is constant with depth for cohesive soils.