BRIDGE PARAPET TESTS CARRIED OUT IN COLLABORATION WITH THE BRITISH ALUMINUM COMPANY

SIX FULL-SCALE IMPACT TESTS WERE MADE ON DESIGNS OF ALUMINIUM BRIDGE PARAPETS WHICH ARE REPRESENTATIVE OF STRUCTURES CONFORMING TO THE GEOMETRY AND STATIC LOADS SPECIFIED IN MINISTRY OF TRANSPORT TECHNICAL MEMORANDUM NO. BE5. SINCE THE MEMORANDUM IS OF AN INTERIM NATURE, THESE TESTS WERE MADE TO FIND THE DYNAMIC BEHAVIOR OF THIS CLASS OF STRUCTURE IN CONTAINING AND RE-DIRECTING CARS OUT-OF- CONTROL AND TO DETERMINE THE OPTIMUM SPACING OF POSTS FOR SATISFACTORY VEHICLE RESPONSE AND CONSISTENT WITH LIMITED DEFLECTION OF THE PARAPETS. IN ALL SIX TESTS THE POSTS IN THE IMPACT ZONE FRACTURED AT THEIR BASES, THUS TRANSFERRING THE LOAD TO MORE DISTANT POSTS AND REDUCING THE SEVERITY OF THE IMPACT. IT WAS FOUND THAT WHEN THE POST SPACING WAS 2.85 M (112.5 IN) AND THE STATIC RAIL STRENGTH WAS 1.6 TIMES ABOVE THE PERMITTED MINIMUM, THE THREE-RAIL GROUP P1 PARAPET DESIGN PERFORMED SATISFACTORILY FOR THE 113 KM/H (70 MILE/H) IMPACT AT 20 DEGREES, THE CAR STAYING CLOSE TO THE PARAPET. A DESIGN FOR A GROUP P2 PARAPET WITH UPPER AND LOWER RAILS CONNECTED BY CLOSELY SPACED VERTICAL BARS FAILED TO RE- DIRECT A CAR STRIKING IT AT 74 KM/H (46 MILE/H) AND 20 DEGREES. WHEN THE VERTICAL INFILL WAS REMOVED AND A THIRD RAIL ADDED VEHICLE RE-DIRECTION WAS ACHIEVED, BUT WITH THE POSTS AT A SPACING OF 3.8M (150 IN) THE CARS VEERED ACROSS THE ROAD. TWO ADDITIONAL RESEARCH TESTS WERE CARRIED OUT; IN ONE A COACH WEIGHING 5140 KG (11300 LB) WAS IMPACTED AGAINST THE GROUP P1 PARAPET AT 73 KM/H (45 MILE/H) AND 21 DEGREES. THE KINETIC ENERGY OF THIS BLOW WAS 1.5 TIMES THAT OF THE CAR AT 113 KM/H (70 MILE/H) AND THE PARAPET FAILED TO CONTAIN THE VEHICLE. IN ANOTHER TEST WITH POSTS DESIGNED NOT TO FRACTURE AT THEIR BASES A CAR WHICH STRUCK THE PARAPET AT 111 KM/H (69 MILE/H) AND 21 DEGREES WAS VERY SEVERELY DAMAGED, BUT STAYED CLOSE TO THE PARAPET AFTER IMPACT. DAMAGE TO THIS PARAPET WAS SLIGHT, AND THE PARAPET MAY BE ABLE TO STAND UP TO A HEAVY VEHICLE IMPACT BUT FURTHER RESEARCH IS REQUIRED TO PROVIDE AN OPTIMUM SOLUTION FOR BOTH CARS AND HEAVY VEHICLES. /A/RRL/

• Supplemental Notes:
  • Rrl Report LR 281, 30 PP, 8 FIG, 3 TAB, 8 PHOT, 2 REF
• Corporate Authors:

  MINISTRY OF TRANSPORT, LONDON (UK)

  ,    
• Authors:
  • JEHU, V J
  • Laker, I B
  • Blamey, C
• Publication Date: 1969

Subject/Index Terms

• TRT Terms: Aluminum; Bridges; Crash tests; Deflection; Geometry; Parapets; Posts; Static loads; Vehicles
• Subject Areas: Bridges and other structures; Highways; Research; Vehicles and Equipment;

Filing Info

• Accession Number: 00208658
• Record Type: Publication
• Source Agency: Road Research Laboratory /UK
• Files: TRIS
• Created Date: Apr 27 1970 12:00AM