Internal force analysis of precast frame under the influence of node semi-rigid

Through using spiral springs to simulate the semi-rigid of nodes connection,this paper developed the beam element stiffness matrix due to different rotation stiffness of the joints at beam end,and established the internal force analysis model of the precast frame under a vertical load,The results show that: under the influence of semi-rigid connection,the girder bending moment of the frame will decrease,while the mid-span bending moment increases;when the ratio of line stiffness of the beam and the relative node stiffness: ψ0.033,the internal forces of frameworks can be calculated through rigid connection;when ψ4.02,the internal forces of frameworks can be calculated through hinged joint;when 0.033≤ψ≤4.02,the influence of node semi-rigid on internal forces of frameworks should be taken into account.