Abstract:  The practical calculation formula for lateral buckling load of the tied-arch bridge with transverse braces in the railway passenger transport line is proposed using the Ritz approximation method. The trial displacement functions are assumed to satisfy the boundary conditions in lateral flexural torsion buckling conditions. The potential energy
formulations for the arch bridge structure under lateral buckling conditions are determined. The critical lateral buckling load for the tied-arch bridge is deduced based on the minimal potential principle. As an example, the lateral buckling load for a tied-arch bridge in a railway passenger transport line is investigated using the proposed method. The comparison is made between the practical method and the buckling analysis of the finite element method. The result shows that the proposed method is easy to apply and can predict the critical lateral buckling load for the tied-arch bridge precisely.