Study on the law of structural response variations considering the joint stiffness characteristics

The joint connection of steel structure usually includes bolt connections, pin connections, welding connections, which are assumed to be hinged or rigid connection in the finite element simulation analysis. It is difficult to reflect the law of the actual structural response using the simulation analysis with such hypothesis for the joint connection, where the differences between the performance of the joint in the simulation analysis and the joint in actual structure are existed. The law of structural response variations considering the joint stiffness characteristics is studied in the paper. The solid element is used to establish a three-dimensional solid model of the joint, the bending moment-rotation curve of the joint in the elastic stage is determined, and the rotational stiffness of the joint is extracted. By releasing the constraint at the end of the beam, the value of the rotation stiffness of the joint is given, while the boundary conditions of the joint are determined, and the structural model considering the characteristics of the joint stiffness is established. Based on the actual construction monitoring system of engineering structure, the influence of the change of joint stiffness on the structural response under different unit load forms is compared and analyzed, and the sensitivity of different joint stress forms to the change of joint stiffness is explored, which provides a theoretical basis for the importance evaluation of joint stiffness in the structural simulation analysis.