Evaluation of mechanical performance and optimization design for lattice girders

Abstract

The present study investigated the mechanical performance of the LG and its cost-efficiency. The analyses were performed using loading capacity test and numerical approach. Influential factors such as main steel bar, diagonal bar, welding and stirrup were considered. First, different cases were designed to investigate the contribution of each component. An experimental system which could simulate the resistance of rock mass was developed. Then, a performance index was introduced to evaluate the relationship between the ultimate loading capacity and cost of construction material. A simple design procedure for engineers to optimize the LG was also provided. After that, a series of plain lattice girders, shotcreted lattice girders were studied and optimized. Meanwhile, refined numerical models were developed in ABAQUS to further validate the results. Finally, the structural performance of lattice arch girders was studied. The results revealed that under the large eccentric mechanical model, the main steel bar on the rock mass side, the diagonal bar, welding length and the stirrup have limited contribution to the ultimate loading capacity of the lattice girders. Thus, the researchers proposed the optimization strategies for the lattice girders: decrease in the diameter of the main steel bar on rock mass side and the diagonal bar, reduction of the welding length, and cancellation the stirrup.