The double lines strengthening elastic-plastic model was developed by simplifying the concrete constitutive law according to Saenz formula. The formulae for the model parameters were given. The structural analysis procedure Algor was taken to conduct the linear elastic and elastic-plastic FEM analysis on the joints of segments. The strain distribution of segment, the displacement of joints, the rotary angle of joints and the tensile force of joint bolts were given. The comparison between FEM calculation and test results was made, which shows that the finite element analysis results correspond with the test results. The FEM analysis results can bean effective measure to observe the distribution patterns of the strain and stress.