PENDULUM IMPACT TESTS ON STEEL W-BEAM GUARD RAILS

The response of a G4(1S) strong post steel w-beam guardrail system to pendulum impacts has been investigated in a series of full-size physic al tests and in simulated experiments using the explicit finite-elemen t analysis code DYNA3D. The physical tests were conducted at the Feder al Outdoor Impact Laboratory at the Turner Fairbank Highway Research C enter of the Federal Highway Administration in McLean, Va. In the pend ulum tests, an 880-kg mass was used to strike the rail perpendicular t o its face. The rail section was attached to steel posts and blockouts and supported in a specially designed fixture. Initial velocities of the pendulum at impact were 9.25, 20, 30, and 35 km/h. Acceleration, f orce, velocity, and displacement histories of the impact event were ob tained from accelerometer data taken during the testing. Data from the DYNA3D simulations of the impact tests compared well with the data ob tained from the full-scale testing. Displacement plots of the deformed shapes of the rails at 25-ms intervals compared favorably with high-s peed film images. Force versus displacement histories showed good agre ement with those obtained from quasi-static experiments. The use of pe ndulum impact tests for screening and evaluation of alternative guardr ail systems is recommended.