Calculation of Stiffness of Vertical Springs
When back calculating the stiffnesses of vertical springs it is necessary to input a typical load in the frame "Vertical springs" that will serve to the determine the spring stiffnesses. This load should be selected such as to characterize the structure behavior as close as possible.
The stiffnesses are determined as follows:
- Typical load is applied to individual piles
- The stiffness of shear vertical springs distributed along the pile is calculated depending on the soil parameters.
- The stiffness of vertical spring at the pile-base is calculated depending on the stiffness of the subsoil below the pile-base and the depth of influence zone. For tensile piles this stiffness is equal to zero.
These stiffnesses are further adjusted according to their location in the pile group - the shear stiffness is reduced by the coefficients equal to 0.5 and 0.1 for the outer and inner piles, respectively.