Substructuring strategy for pseudo-dynamic testing of steel lattice towers

Abstract

Abstract: Lattice towers are the most commonly used structures in the field of overhead power transmission lines. In the design process of transmission lines, there are several methods for the evaluation of their capacity. The most common design method involves the use of three-dimensional linear elastic truss analyses to evaluate the axial forces in the pin-ended members. The resulting design is normally validated by full-scale experimental tests. These tests are very expensive and time-consuming. Moreover, the rarity of the testing facilities represents an additional difficulty. Hence there is an interest of using substructured pseudo-dynamic testing methods in which the experimental substructure, tested in a laboratory environment, interacts with a numerical model to emulate the structural behaviour of a complete structure. This method has several advantages but requires several preliminary analyses and planning for defining the critical substructure, dynamic parameters, and the setup’s flexibility. This work aims to develop a completely numerical substructuring strategy using the finite element software Code_Aster to ensure relevance and simplify the preparation and planning of pseudo-dynamic tests on lattice towers. An example of a lattice tower, under quasi-static load case is presented and compared with reference numerical analyses’ results. The effect of dynamic parameters (time step, damping ratio and load rate) on the emulated structure’s behaviour is analyzed in detail. Finally, the effects due to the flexibility of a simplified test set-up on the accuracy of the test results is studied.