ANTI-WIND CAPACITY CHECK AND COLLAPSE ANALYSIS OF EXISTING TRANSMISSION TOWER

"With the implementation of the new code for the design of overhead transmission line in China, the design check, maintenance and reinforcement for the existing transmission towers are indispensable. In this paper, based on an existing transmission line project, firstly, the differences of the wind load calculations between different design codes are analyzed contrastively, and the safety stock of the tower primary members is checked. Then, the tower’s ultimate bearing capacity is analyzed, in which the parameters of the fiber hinges are determined by the solid element model simulation. Last, the tower collapse process is simulated, and a similar accident case is investigated briefly. It is revealed that by the new code, the evaluated safety stock of this existing tower decreases obviously; at the 1/3 of the tower height and the position under the lowest crossarms, the primary members perform as the weak parts; and the progressive collapse resistance of the tower is low, which is triggered by the primary member buckling. Therefore, to reinforce the weak parts of the existing towers, increase the redundancy to resist a local failure and avoid the total collapse of the entire structural system is imperative."