Based on the concept of basic internal force and generalized constraint matrix, a new method was proposed for calculation of the internal force of truss structures.

It is very important for calculating the internal force of foundation to analyze the interaction of foundation and ground.

Using program of singular function to calculate internal forces of bending pole;

The analysis of internal force for steel frame with semi-rigid connections;

Influences of different directional unloadings upon displacements and internal forces of retaining structure for foundation pit;