Effect of loading rate on the shear performance of ACC structures

The shear mechanical properties and deformation damage mechanism of the double structural planes of traditional anchor cables and new anchor cables with C-shaped tube structures (abbreviated as ACC) under different loading rate conditions were investigated through experimental and numerical simulation analyses. Dual structural face shear tests were conducted at shear displacement loading rates of 2, 10, 20, 30, and 40 mm/min under 55 MPa concrete specimen strength and 200 kN preload, with shear deformation curves, peak structural shear loads, steel wire damage patterns, and structural plane shear strength contributions as the main parameters considered. The results show that the loading rate significantly affects the shear performance of the structure. Within a certain loading rate interval, influenced by the damage accumulation rate and the strain rate strengthening effect, the structure exhibits characteristics of strength weakening and strengthening, respectively, with a large variation interval in shear load-carrying capacity. Near the structural plane, the support structure shows a combination of tensile and shear damage. However, the ACC structure, due to the presence of the C-shaped tube, exhibits lower stress concentration effects, reduced fluctuation in the test curve, and significantly weakened internal steel wire damage compared to traditional anchor cables. Meanwhile, the numerical model of the double shear test of the ACC structure, constructed based on the test results, exhibits high accuracy. Numerical simulations of dynamic loading tests demonstrate that the anchoring system formed by the ACC structure has a good energy absorption effect, which becomes more pronounced with increasing impact energy. Under high-speed impact, the ACC structure is significantly affected by the strain rate reinforcement effect, with higher shear load capacity at greater impact velocities.