Constant Spacing Method
Using this method, the user specifies the Minimum Distance from Curb between the left curb and the left wheel of the truck or the right curb and the right wheel of the truck. The Constant Center to Center Spacing between two consecutive live load positions is also specified. Once the user inputs these two values, the program will generate the first position by placing the truckload at the minimum distance from the left curb. The next position is obtained by moving the live load (truck) to the right of the first position by the constant center-to-center spacing. This process is continued transversely across the bridge width as long as the distance between the right wheel of the truck and the right curb is greater than or equal to the minimum spacing allowed.
Once all the live load positions are determined, Substructure creates the different live load combinations depending upon the number of loaded lanes selected.
Setting | Description | ||||||
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Minimum Distance from Curb (For Constant Spacing) |
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Center to Center Spacing (For Constant Spacing) | This is the user-specified, center-to-center spacing for placement of various live loads (lane, truck or tandem) for the generation of different live load positions. For example, if center-to-center spacing = 5 ft, Substructure will first, determine the initial position of the live load from the left end of the bridge (first live load position). Assume that the first position is 6.5 ft from the left end; the program will then add the center-to-center spacing to the first position to obtain the second live load position, which is 11.5 ft away from the left end of the bridge. Substructure will repeat the same process by starting from the right side of the bridge. | Default values: 10 ft or 3 m. | Range of values that can be input: 1 to 20 ft (or 0.3 to 6.0 m). |