In this paper a method of equi valent stiffness is applied to calculate the critical load for compression bar with lateral struts.

This article calculated the choice of optimum position of a superfluous lateral support on variable section press bar and one or two superfluous lateral support on isosection press bar in all kinds of supports with the method of transmit matrix given by the writer in reference article, which has a definite reference value to the engineering reality.

Computer aided design for stay bar of piling ship;