Research on the control limits of cable length errors of cable-strut tensile structures for prestressed relaxation under load effect

Abstract

Cable-strut tensile structures (CSTS) are mainly composed of cables, and the cable length errors are bound to exist in the manufacturing of cables. The cable length errors have significant impacts on the mechanical properties of CSTS under load effects. Meanwhile, CSTS generally uses flexible membrane material as roofs, therefore cable length errors will result in the wrinkle of roofs and then cause the secondary accumulation effects of rain and snow load. Therefore, it is necessary to reasonably control the manufacturing errors of cable length. In order to solve the problem, the method of solving the control limits of cable length errors of CSTS is proposed due to the prestressed relaxation under load effects. The reliability index of CSTS is firstly given based on the reliability theory. Then, based on the reliability index and the criterion of prestress relaxation under load effect, the critical state equation and constraint inequality group are constructed, and the coefficient matrix of constraint inequality group is derived. Meanwhile, the nonlinear finite element method for solving the coefficient matrix of constraint inequality group is proposed. The procedure of solving the control limits of cable length errors of CSTS is given based on the proposed method. The crossed spoke cable-truss structure is taken as an example to verify the feasibility of the new method. The research contents provide an effective solution for controlling cable length errors of CSTS for prestressed relaxation under load effect.