Truck Loads

Case 1:

The first position is obtained by placing the left wheel of the truck at a distance of 2 feet from the face of the left curb per AASHTO. The next position is obtained by moving the centerline of the truck 10 feet to the right so that a minimum of 4 feet is maintained between the right wheel of the original position and the left wheel of the new position. This process is repeated and additional positions are created until the minimum distance requirement of 2 feet between the right wheel of the truck and the face of the right curb is not violated.

Figure 1. Truck Loads - Case 1

Case 2:

Substructure repeats the same process as Case 1, but starts by placing the right wheel of the truck at a distance of 2 feet from the face of the right curb. Additional positions are obtained by moving the centerline of the truck in 10 feet increments transversely across the bridge until the minimum distance requirement of 2 feet between the left wheel of the truck and the face of the left curb is not violated.

Figure 2. Truck Loads - Case 2

Case 3:

Next, the left wheel of the truck is placed directly on each of the bearings and additional positions are created by moving the centerline of the truck 10 feet to the left and to the right of the previous positions until the minimum distance requirement of 2 feet between either of the two wheels and the face of the curb is not violated.

Figure 3. Truck Loads - Case 3

Case 4:

Next, the right wheel of the truck is placed directly on each of the bearings and additional positions are created by moving the centerline of the truck 10 feet to the left and to the right of the previous positions until the minimum distance requirement of 2 feet between either of the two wheels and the face of the curb is not violated.

Figure 4. Truck Loads - Case 4

Case 5:

Next, the centerline of the truck is placed directly on each of the bearings and additional positions are created by moving the centerline of the truck 10 feet to the left and to the right of the previous positions until the minimum distance requirement of 2 feet between either of the two wheels and the face of the curb is not violated.

Figure 5. Truck Loads - Case 5

Case 6:

Lastly, the centerline of the truck is placed coincident with the center of each of the columns and additional positions are created by moving the centerline of the truck 10 feet to the left and to the right of the previous positions until the minimum distance requirement of 2 feet between either of the two wheels and the face of the curb is not violated.

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