Experimental and numerical study on the effective length of tower cross bracing

Abstract

Based on the present study, a new design formula for the effective length coefficient of the commonly used cross bracing in transmission towers is proposed. A total of 22 structural tests were conducted considering the interaction in the buckling of cross bracing. The test results, including the failure modes and load-response histories, were reported. The numerical simulations were conducted and validated using multiple comparisons. The ultimate strengths, calculated by the Chinese design code of DL/T 5154, are not sufficiently accurate. An extensive parametric study based on a calibrated finite-element model was conducted to investigate several influential parameters. Implicit theoretical equations for effective length were formulated and evaluated. The numerical results were subsequently used to obtain a new design formula for the effective length coefficient associated with the stress ratios. It is shown that the proposed formula, which was obtained from piecewise linear fitting, improves the consistency and reliability of the prediction of the ultimate strength.