DEVELOPMENT OF EFFECTIVE ROCKFALL BARRIERS

As a part of the construction of Interstate 70 through Glenwood Canyon , in Colorado, three new types of barriers for protection against rock fall were developed through a program of prototype testing, numerical simulation of rockfall events, and analysis of barrier response to imp act by boulders. New barriers include a suspended pendulum system that attenuates the kinetic energy of falling boulders, a flexibly mounted fence of steel cables and mesh, and a free-standing mechanically stab ilized earth wall. The capacity of rockfall barriers, stated as a limi ting translational kinetic energy of falling boulders, ranges from 41 kJ (30,000 ft . lb) for light fences to more than 1,400 kJ (1,000,000 ft . lb) for mechanically stabilized earth walls. Earth walls can halt falling boulders that weigh as much as 13,700 kg (30,100 ib). The thr ee barriers reported here are useful as options to ditches, berms, rig id fences, and rigid walls of rockfall protection for highways. This p aper provides a summary of barriers developed in Colorado, a summary o f associated numerical simulation and analytical tools developed speci fically for the barriers, as well as a guide to more detailed informat ion on development and testing programs for rockfall barriers.