Failure mechanism of steel arch trusses: Shaking table testing and FEM analysis

To study the failure mechanism of steel arch truss structures that are subjected to severe earthquakes, a series of shaking table tests were conducted, and the results are discussed in this paper. Furthermore, the effect of bracing forms on the structure failure mode and the cumulative damage effects on the member internal forces were evaluated using the Finite Element Method (FEM). The results from the numerical model are compared with the experimental measurements in terms of displacement, acceleration, steel strain and amplification factor of the structural model. The comparison shows that the numerical results are significantly consistent with the experimental measurements. Under severe earthquakes, structural cumulative damage and plastic deformation increased, whereas the structure stiffness declined, which leads to structural failure. The failure load of the structure was 0.8-1.0g, and in-plane anti-symmetric deformation was found in the main trusses after loading. The maximum strain in the test model is larger than those in the cumulative damage model and the ideal elasto-plastic model by 7-15% and 8-26%, respectively. Increasing the number of rigid tied bars slightly enhances the stiffness of the main truss, whereas using cross diagonal bracings enhances the stiffness of the main truss by 2.9 times.