Assessment of the effect of residual stresses on the mechanical behavior of steel lattice transmission towers

Abstract

Abstract: Power transmission lines predominantly involve lattice towers, which are typically composed of steel angle members connected together by means of bolted joints. An effective design of such structures requires the consideration of a range of complex phenomena likely to affect either the carrying capacity or the failure mode. In practice, simple numerical models are combined with standard design equations to consider these effects. A few advanced numerical models reported in the literature deal with eccentricities, stiffness of the connections, and joint slippage. However, the impact of residual stresses on the global behavior of lattice towers is not addressed in prior works. In this work, the influence of residual stresses is studied numerically using the finite element software Code_Aster. The proposed model employs multi-fibre beam elements to model the elastoplastic angle members, and discrete elements to represent the bolted connections. Both the connection eccentricity and the rotational stiffness of connections are modeled. The associated problem is solved in an incremental way, so as to deal with geometric and material nonlinearities, and the results are compared with experimental tests. Considering residual stresses in advanced models is an important step for the numerical evaluation of the failure of lattice towers.