Live Load Terms
| Setting | Description |
|---|---|
| ID | The name of the live load. |
| Description |
A short description of the specific live load. |
| Truck Width |
Width of the truck, which is 10 ft (3048 mm) for most trucks (for calculating live load distribution factors using lever rule). |
| Wheel Spacing | Transverse spacing between wheels, which is 6 ft (1829 mm) for most trucks (for calculating live load distribution factors using lever rule). If the option to use refined methods of analysis to compute distribution factors is selected, and the Wheel Spacing is not equal to the standard gage width of 6 feet, then the distribution factors are recomputed using the actual user input value of the wheel spacing based on the grillage model as specified in Appendix F. This option is only available during the load rating phase of the analysis, and all design results use the standard gage width to compute even the refined distribution factors. This modified wheel spacing is not used to compute DFs using Lever Rule. |
| Lane Load | The adjustable UDL (uniformly distributed load) magnitude. The uniform lane load is adjustable; that is, the program will adjust the location of the load to maximize the bending moment or shear when calculating the envelopes. |
| Truck Load |
The truck load consists of one or more concentrated axle loads with variable spacing between them. See Example below. Example for Design Truck Load First Axle Intensity: 8 kips (35 kN) Remaining Axles Parameters: |
| Increment |
Defines spacing between axles. Precast/Prestressed Girder will first analyze a truck using the minimum spacing then continually increment this spacing by the value of the spacing increment. See example below. Example for Increment If you specify the spacing increment between axles 2 and 3 equal to 8 ft for a design truck, three analyses will be performed. For spacing between Axles 1 and 2, the spacing will be fixed at 14 ft, since the minimum and maximum spacing are both 14 ft and the increment is zero. For spacing between Axles 2 and 3, where minimum spacing is 14 ft and maximum spacing is 30 ft), three spacing will be considered, 14 ft, 22 ft, and 30 ft. However, if you enter 18 as the spacing increment for a design truck, the only spacing between Axles 2 and 3 that will be used is 14 ft and 30 ft. When the program calculates the next spacing as 14 + 18 = 32 ft, it finds that it is larger than the maximum spacing (30 ft) and therefore will not use it. |
Additional Uniform Load
| Setting | Description |
|---|---|
| Preceding and Trailing Uniform Load |
You can specify additional preceding and trailing uniform loads respective to the LFD (Truck type) and LRFD (Permit Vehicles type) component. Typically used to simulate railroad loads, such as AREA (Cooper E-80) loads or special trucks. These loads are adjustable; the program will adjust the location of the load to maximize the bending moment or shear when calculating the envelopes. |
| Intensity |
The intensity of the preceding and trailing loads. |
| Distance | For preceding load, the distance from the truck loads first axle to the end of the preceding load. For trailing load, the distance from the truck load last axle to the beginning of the trailing load. |
| Length | The length of the preceding or trailing load. |
