Progressive collapse analysis of long-span transmission tower-line system under multi-component seismic excitations

Research on progressive collapse has a practical significance for long-span transmission tower-line system. Considering material damage effect, the Tian-Ma-Qu model is used to capture the nonlinear behaviors of element. The damage index is selected as the failure criteria of element. A three-dimensional finite element model, which consists of steel-latticed towers supporting transmission lines, is created in ABAQUS. Seven seismic records are selected based on site conditions and adjusted to match the design spectrum required. The collapse mechanism of the long-span transmission tower-line system under El Centro is investigated, and the incremental dynamic analysis is conducted to obtain the collapse resistant capacity of the structure. The amplification factor is proposed to evaluate the collapse resistant capacity of the structure. The displacement responses of electricity transmission towers are studied based on inter-segment displacement ratio results. The analysis results can provide a meaningful reference for the seismic design of long-span transmission tower-line system.