ANALYSIS OF INTERNAL FORCE OF BOX FRAME WITH CONSIDERING ELASTIC RESISTANCES OF FOUNDATION

Starting from the differential equations for defletion of beam on elastic foundation, the stiffness matrices for beam element on elastic foundation are developed by using matrix trans. formation according to the finite element method. During calculation the elastic resistances of foundation were taken into account. These stiffness matrices can be used to determine box frames on or underground and are characterized by simplicity and practicality.