AN ANALYTICAL METHOD FOR EVALUATING THE DEFLECTION AND LOAD-BEARING AND ENERGY ABSORPTION CAPACITY OF ROCKFALL RING NETS

In this study, an analytical method for evaluating the structural performance, including maximum deflection, load-bearing, and energy absorption capacity of a steel wire-ring net, was proposed to effectively design the ring net of the flexible barrier systems. Puncture tests of the ring nets and two-point traction tests of the three-ring chains with various wire-ring specifications were conducted. Correlation analysis was used to test the results between ring nets and chains, revealing that three structural performance indicators of the test specimens were strongly related. The ring net's structural performance was affected specifically by ring chains on the shortest load transfer path. Accordingly, a three-ring chain with a flexible boundary corresponded to a fibre-spring element. A three-dimensional analytical model of the ring net was established. Explicit formulas for computing the three indicators of the ring net were derived. Comprehensive quasi-static and impact tests, using different shapes and sizes of punching devices, were conducted, providing valuable data to calibrate and validate this analytical method. The ability of the model in yielding consistent results when implemented at the structure scale was then assessed, based on the data of full-scale impact tests on a 1500kJ-energy rockfall barrier. Lastly, the effects of various factors, such as single ring geometry, the length-width ratio of the net, loading area size, boundary stiffness, and load rate, influencing the structural performance indicators of the ring net were investigated, respectively. (c) 2022 The Institute of Steel Construction. All reserved.