Citation

Wiles EO, Kimball CE, Michie JD. Transp. Res. Rec. 1977; 631: 82-87.

Copyright

(Copyright © 1977, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The inadequate performance of many current bridge-railing systems in vehicle collisions has resulted in a large number of injuries and fatal accidents. An analysis of representative bridge-railing designs submitted by 44 highway agencies in 1974 showed that most did not fully conform to the 1973 American Association of State Highway Officials specifications. Most of these bridge-railing installations have been in service for more than 10 years and were designed to less restrictive requirements. An alternative to replacing inadequate installations with conforming systems is to upgrade the existing installation with a modification or retrofit design. To reduce the number of potential retrofit designs, existing bridge-railing systems can be grouped in four categories according to their profile geometries and features. Each category has its own constraints for retrofit modification (i.e., curbs, parapets, and such), but a properly conceived retrofit design for a category can be adapted to any bridge-railing system in the category. About 82 percent of the existing systems reported in the survey can be placed in Southwest Research Institute categories II and III. Five retrofit designs for these categories were developed and evaluated by a 22-vehicle crash-test program. These five designs are judged suitable for carefully monitored in-service use to up-grade the safety performance of substandard systems.