摘要: |
Testing, evaluation, and analysis of two types of rockfall barriers are reported. Rockfall barriers are designed to withstand impacts by falling boulders and are used to protect roadways and structures. Among several types of barriers in use by transportation departments, two designs--a flexible cable-fence barrier and a freestanding mechanically stabilized earth (MSE) barrier--have been developed by the Colorado Department of Transportation in a program of prototype testing and dynamic analysis. In tests, full-size prototype barriers were subjected to impacts by boulders falling freely down a natural slope. The velocity and kinetic energy of the rockfall and the performance of the barrier are basic findings of tests. Simulation of test impacts in dynamic analysis provides information about the load demand on components of barriers. Test data are used to calibrate analytical procedures. Three prototype cable fences have been tested. The fences have proven rockfall capacities up to 129 kJ (95,000 ft-lb) and can halt boulders as heavy as 2,950 kg (6,500 lb). Three prototype MSE barriers have been tested. One prototype was repaired after initial testing and then retested to examine the performance of repairs. MSE barriers offer rockfall capacities in excess of 1,360 kJ (1,000,000 ft-lb) and have been observed to halt boulders as heavy as 13,700 kg (30,100 lb). |