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Figure  7-28.Correct  placement  of  payload.
Loading  Equipment

Equipment Operator Basic - Beginning construction equipment operators manual
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to  the  manufacturer’s  recommendations  for  the specified  operating  condition;  that  is,  ideal,  moderate, or severe. IDEAL  CONDITION.—  An  ideal  condition  is when a truck is operated over improved, level roads, such  as  asphalt  or  concrete,  at  constant,  relatively moderate  speeds  with  no  adverse  weather  or  road conditions.  Under  these  conditions,  recommended payload equals 100 percent of maximum permissible payload. MODERATE CONDITION.— A moderate con- dition is when a truck is operated at high speeds over improved highways, such as asphalt or concrete, with or without long or steep grades. Moderate conditions also include  operating  at  moderate  speeds  over  semi- improved roads with gravel or equivalent surfacing, in gently rolling country with few steep grades and no adverse  weather  or  road  conditions.  Under  these conditions,  recommended  payload  equals  80  percent  of maximum permissible payload. SEVERE CONDITION.— A severe condition is when the vehicle is operated off the highway on rough or hilly terrain or over unimproved or pioneer access roads with deep ruts, holes, or steep grades. These conditions  also  include  operating  where  traffic  has created deep holes or ruts in heavy snow, covering normally good city streets or highways. Under these conditions,  the  recommended  payload  equals  64  percent of the maximum permissible payload. Weight  Distribution Distribution of cargo has a definite bearing on the life of tires, axles, frame, and other parts of the vehicle. The fact that a truck or trailer is not loaded beyond its gross vehicle weight capacity does not mean that the individual tires and axles may not be overloaded by faulty distribution of the cargo. Additionally, states have maximums for GVW, GCW, and axle weights. Axle weights   prevent   the   overloading   of   bridges   and roadways.  Some  examples  of  proper  and  improper placement of the load are shown in figure 7-28. To load a truck or tractor-trailer properly, you have to determine the center of the payload. In a truck, the position of the center of the payload is the center of the body  or  the  point  midway  between  the  rear  of  the driver’s cab and the tailgate. In a tractor-trailer unit, the position of the center of the payload is roughly the center of the trailer body, because the front wheels of the tractor seldom carry any of the payload. When you are loading, ensure that the maximum capacity of the vehicle is not 7-25 Figure  7-29.—Distribution  of  weight. exceeded over any one axle and, if possible, that loads are distributed so there is less-than-maximum axle loading. Examples of approximate distribution of total weight are shown in figure 7-29. The  payload  weight  must  be  distributed  over  the body properly so the percentage of weight carried by the front axle and that carried by the rear axle equals the ratio  for  which  the  vehicle  was  designed,  as  shown  in figure 7-29. Loading Cargo The tractor-trailer can be adapted to transport various  types  of  materials,  such  as  fragile,  bulky, compact,  dense,  rough  and  high  center-of-gravity  items. To accommodate a variety of items, you must plan the load, properly prepare the tractor-trailer, and secure the load to the vehicle. Securing the load by restraining it with proper lines, cargo straps, chains, or fastened by tie-downs or binders should keep it from shifting or falling off the vehicle. Should a load fall from a vehicle, it  could  foul  underpasses,  culverts,  bridge  abutments, and create a hazard to pedestrians. Protect fragile items







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