InTrans / Aug 14, 2018
Design and evaluation of two bridge railings for low-volume roads
The U.S. Department of Agriculture (USDA) Forest Service, Forest Products Laboratory (FPL) and Headquarters Engineering Staff, in cooperation with the Midwest Roadside Safety Facility undertook the task of developing bridge railing systems for roads with low traffic volumes and low speeds. Two low-cost bridge railing systems were developed and successful full-scale crash tests were conducted for their use on timber bridge decks using longitudinal lumber laminations. A curb-type timber railing system was designed to redirect a 3/4-ton pickup truck hitting at a speed of 24 km/hr (15 mph) and an angle of 15 degrees. The curbtype rail system used square, trapezoidal, or rectangular rail shapes. A flexible railing system consisting of steel W-beam supported by breakaway timber posts was designed to redirect a 3/4-ton pickup truck hitting at a speed of 50 km/hr (31 mph) and an angle of 25 degrees. The flexible railing system was developed according to Test Level 1 of NCHRP Report 350, Recommended Procedure for the Safety Performance Evaluation of Highway Features.