Abstract: Based on the stability function， a calculation method for solving the critical force of the support structure system was given， and the calculation formula for the critical force of three double-layer support structure systems at different load positions was derived. The results show that the analytical solution derived from formula based on the stability function theory is similar to the numerical solution of the second-order elastic analysis with an error less than 3%. The accuracy of the calculation method for the critical force of the support structure system was verified by the the theoretical and experimental values of the total bearing capacity of the double-layer 1~3-span rocking column support structure system. The critical force calculation method of the support structure system provides a theoretical basis for engineering applications due to its universal applicability and high calculation accuracy.

Key words: support structure; stability analysis; critical force; effective length factor; sway column