Abnormmally heavy and abnormally sized vehicles traveling under special permits issued by state highway departments are becoming an increasingly common sight on our nation's highways. These heavy and oversized vehicles, necessary, in part, by our advanced technology, have created the potential for rapid deterioration of the highway system. Thus a need exists for the development of a satisfactory method for determining the effects of these vehicles on highway pavements in order that the destructive effects of these overloads may be assessed and/or alternative methods of distributing the load may be determined such that minimal damage will be experienced by the pavement. Maximum loads carried on these truck-tractor, jeep, low boy-tractor or dolly types of vehicles can be as high as 1,000,000 pounds with the vehicle possessing 116 wheels. The number and distribution of axles and wheels are varied relative to the loads which the vehicle is to support. Section I of this report describes a means of determining if an abnormally heavy load could operate on a flexible pavement which has been developed based upon the U. S. Army Corps of Engineers flexible pavement design procedures. This design procedure can also be used to indicate what can be done to an abnormally heavy vehicle supporting system in order to permit the vehicle to use a roadway. The methodology presented herein makes use of equivalency factors to relate traffic of an abnormally heavy vehicle to traffic of a standard load. This equivalency will indicate the amount of life that will be used up by the heavy vehicle and provide a basis for determining if the vehicle can be permitted to use the road. In Section II of the report a method is described which will allow the engineer to determine the effect of abnormally heavy loads on existing portland cement concrete highway pavements. This method is intended to be a simplified approach and is based on the use of current technology. New concepts are not utilized, but rather existing pavement design methods have been organized into a framework that can be utilized for the solution of the problem.

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Filing Info

  • Accession Number: 00272048
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Oct 5 1974 12:00AM