DYNAMIC IMPACT PRESSURES GENERATED UNDER ROADS BY SPRUNG AND UPSPRUNG VEHICLES

THE INVESTIGATION WAS MADE TO DETERMINE (1) WHETHER UNSPRUNG VEHICLES USED FOR CONSTRUCTION AND AGRICULTURAL PURPOSES ARE LIKELY TO CAUSE MORE DAMAGE TO ROADS THAN SPRUNG VEHICLES AND (2) WHETHER REDUCTION OF TIRE INFLATION PRESSURE WOULD REDUCE THE DAMAGE. MEASUREMENTS WERE MADE OF THE VERTICAL PRESSURE GENERATED IN THE SOIL SUBGRADE BENEATH THE ROAD, AS THIS IS KNOWN TO GIVE AN INDICATION OF THE DAMAGE TO THE ROAD STRUCTURE. COMPARISONS WERE MADE BETWEEN THE PRESSURES GENERATED BY SPRUNG AND UNSPRUNG VEHICLES TRAVELLING ALONG A SMOOTH ROAD AND WHEN TRAVERSING A PLANK, USED TO SIMULATE A SEVERE SURFACE IRREGULARITY. THE NUMBER OF PRESSURE PULSES CAUSED BY THE "BOUNCING" OF THE VEHICLES AFTER CROSSING THE PLANK WAS OBTAINED BY MEASURING THE VERTICAL ACCELERATIONS OF THE AXLE AND BODY. THE EFFECT ON THE SOIL PRESSURES OF CHANGING THE TIRE PRESSURES OF THE UNSPRUNG VEHICLES WAS ALSO INVESTIGATED. THE GENERAL CONCLUSION IS THAT THE DAMAGE CAUSED TO ROADS BY UNSPRUNG VEHICLES SIMILAR TO THOSE TESTED WHEN OPERATING AT THE MANUFACTURERS' RECOMMENDED TIRE PRESSURES AND NORMAL WORKING SPEEDS, WOULD NOT BE GREATER THAN THE DAMAGE CAUSED BY CONVENTIONALLY SPRUNG VEHICLES OF SIMILAR WHEEL LOAD. /RRL/A/

• Supplemental Notes:
  • Rrl Rpt Lr 137 24 PP, 8 FIG, 5 TAB, 5 PHOT, 2 REF
• Corporate Authors:

  MINISTRY OF TRANSPORT, LONDON (UK)

  ,    

  Road Research Laboratory /UK

  ,    
• Authors:
  • POTTER, J F
• Publication Date: 1968

Subject/Index Terms

• TRT Terms: Axles; Defects; Dynamics; Highways; Impacts; Measurement; Pressure; Soils; Springs (Vehicles); Subgrade (Pavements); Tires; Vehicles; Wheel loads
• Uncontrolled Terms: Highway damage
• Subject Areas: Geotechnology; Highways; Vehicles and Equipment;

Filing Info

• Accession Number: 00219313
• Record Type: Publication
• Source Agency: Road Research Laboratory /UK
• Files: TRIS
• Created Date: Jun 1 1970 12:00AM