BRIDGE RAIL SERVICE REQUIREMENTS AS A BASIS FOR DESIGN CRITERIA
FULL SCALE CRASH TESTS HAVE BEEN CONDUCTED ON BRIDGE RAILINGS IN RECENT YEARS, BUT THERE IS NEED FOR A DEFINITION OF BRIDGE RAILING SERVICE REQUIREMENTS. A STUDY WAS CONDUCTED TO DEVELOP A FUNDAMENTAL CONCEPT OF THE PURPOSE THAT RAILINGS AND THEIR COMPONENT PARTS, SUCH AS SUPPORT POSTS AND APPROACH ELEMENTS, ARE EXPECTED TO SERVE UNDER VARIOUS SITE CONDITIONS, SPEED LIMITS, AND OTHER OPERATIONAL CONDITIONS. SEVERAL STATE HIGHWAY DEPARTMENTS WERE VISITED TO PROVIDE A CROSS-SECTION OF THE BRIDGE RAILING SYSTEMS EMPLOYED IN THE SEVERAL STATES. ACCIDENT INFORMATION FURNISHED BY SEVERAL HIGHWAY DEPARTMENTS WAS REVIEWED. THIS REVIEW INDICATED THAT APPROXIMATELY 35 PERCENT OF FATAL ACCIDENTS RESULTING FROM COLLISIONS WITH RAILING SYSTEMS OCCUR AT THE APPROACH END. AN OBSERVATION WAS MADE THAT APPROACH RAIL-BRIDGE RAIL JUNCTURE MUST PROSSESS STRUCTURAL COMPATIBILITY AS WELL AS ALIGNMENT COMPATIBILITY. A SAFE BRIDGE RAILING SHOULD RESTRAIN A VEHICLE WITHOUT POCKETING, SNAGGING, OR SEVERE REDIRECTION. A MATHEMATICAL EXPRESSION WHICH WAS DERIVED FOR DETERMINING IMPACT FORCES IS PRESENTED. THIS RELATIONSHIP ASSUMES THAT A COLLISION IS IMMINENT AT A FIXED SPEED AND ON A FIXED COLLISION COURSE DEFINED BY AN ANGLE. USING THIS RELATIONSHIP, IT IS POSSIBLE TO COMPUTE REALISTIC VALUES OF IMPACT FORCES WHICH MIGHT BE EXPECTED WHEN A VEHICLE COLLIDES WITH THE BARRIER RAILING. THE SERVICE REQUIREMENTS FOR A BRIDGE BARRIER RAIL SYSTEM ARE: (1) THE BRIDGE BARRIER RAIL MUST RESTRAIN THE VEHICLE, (2) A BRIDGE APPROACH RAIL IS REQUIRED AND IT MUST PREVENT A VEHICLE FROM HITTING THE END SECTION OF THE BRIDGE BARRIER RAIL, (3) THE BRIDGE BARRIER RAIL SYSTEM MUST BE DESIGNED TO MINIMIZE THE VEHICLE DECELERATIONS, (4) THE VEHICLE IMPACT MUST NOT DISLODGE ANY ELEMENTS OF THE BARRIER SYSTEM, (5) ALL ELEMENTS OF A BARRIER SYSTEM MUST BE SO DESIGNED THAT REPAIRS CAN BE MADE QUICKLY AND WITH A MINIMUM OF SPECIAL EQUIPMENT, (6) THE BRIDGE BARRIER RAIL SYSTEM SHOULD BE DESIGNED SO THAT OTHER SERVICE REQUIREMENTS WILL BE FULFILLED IF A SECOND VEHICLE COLLISION WERE TO OCCUR, (7) CURBS WHICH EXTEND HORIZONTALLY MUST NOT BE ALLOWED ON THE VICINITY OF BRIDGE STRUCTURES, (8) BRIDGE STRUCTURES INTENDED TO HANDLE PEDESTRIAN TRAFFIC MUST BE DESIGNED TO PROVIDE MAXIMUM PROTECTION TO THE PEDESTRIAN, (9) THE TRAVELING PUBLIC SHOULD NOT BE REQUIRED TO REACT IN ANY MANNER TO THE FACT THAT IT IS TRAVELING ON A BRIDGE, (10) THE BRIDGE BARRIER RAIL MUST ALLOW GOOD VISIBILITY TO THE TRAVELING PUBLIC, (11) THE BRIDGE RAIL SYSTEM MUST REQUIRE A MINIMUM OF MAINTENANCE, AND (12) THE FINAL DESIGN OF A BRIDGE BARRIER RAIL SYSTEM BASED UPON A RATIONAL APPROACH SHALL BE SUBJECTED TO FULL SCALE DYNAMIC TESTS.
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Supplemental Notes:
- 13 Pp, 13 REF
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Authors:
- Olson, R M
- Publication Date: 1968-12
Media Info
Subject/Index Terms
- TRT Terms: Bridge approaches; Bridge railings; Crash rates; Crash tests; Crashes; Dynamic tests; Fatalities; Impacts; Maintenance; Mathematical analysis; Pedestrian safety; Testing; Vehicles; Visibility
- Old TRIS Terms: Pedestrian protection
- Subject Areas: Bridges and other structures; Design; Highways; Maintenance and Preservation; Research; Safety and Human Factors; Vehicles and Equipment;
Filing Info
- Accession Number: 00208914
- Record Type: Publication
- Files: TRIS
- Created Date: Apr 28 1994 12:00AM