ROAD STRESS BY ALL VEHICLES AND MODIFICATION OF THIS STRESS BY HIGHER AXLE LOADS

STRASSENBEANSPRUCHUNG DURCH ALLE KRAFTFAHRZEUGE UND IHRE VERAENDERUNG DURCH HOEHERE ACHSLASTEN

A METHOD OF CALCULATING THE REPRESENTATIVE DISTRIBUTION OF AXLE LOADS IS DESCRIBED. STARTING FROM THE NUMBERS OF COMMERCIAL VEHICLES IN THE COUNTRY AND AVERAGE ANNUAL MILEAGES, THE DISTRIBUTION FUNCTION FOR THE REAR AXLE LOAD IS CALCULATED BY MEANS OF DEGREES OF LOADING AND AXLE LOAD DISTRIBUTIONS. A COMPARISON OF DISTRIBUTION CALCULATED IN THIS WAY AND MEASURED AXLE LOAD DISTRIBUTION SHOWS GOOD AGREEMENT. ROAD STRESS IS EXPRESSED PROPORTIONALLY TO THE 4TH POWER OF THE AXLE LOAD AND TOTAL ROAD STRESS BY ALL VEHICLES AS A SUM OF THE INDIVIDUAL STRESSES. THE EFFECTS ON TOTAL ROAD STRESS CAN BE OBTAINED FROM THE AXLE LOAD DISTRIBUTIONS OF INDIVIDUAL COMMERCIAL VEHICLES IF TECHNICAL FEATURES ARE MODIFIED. AN EXAMPLE SHOWS HOW THE AXLE LOAD DISTRIBUTION AND THE ROAD STRESS CHANGE IF THE PERMISSIBLE TOTAL WEIGHT OF INDIVIDUAL VEHICLES IS INCREASED. AS EXPECTED THE TOTAL ROAD STRESS INCREASES. FROM THE CALCULATED AXLE LOAD DISTRIBUTION ONE SEES A DECREASE IN THE FREQUENCY OF AXLE LOADS OF 6-9 TONS, AND A SIMULTANEOUS INCREASE IN 10 TON AXLES. BY MODIFYING TYRES AND DECREASING DYNAMIC WHEEL LOADS HOWEVER, THE TOTAL STRESS ON THE CARRIAGEWAYS BROUGHT ABOUT BY ALL COMMERCIAL VEHICLES COULD BE LESS THAN THE PRESENT STRESS.