Caltrans Permit Live Loads

[CivilStructural07]

Does anyone know the axle spacing between any one set of axles which produce the 48 kip loading? Or if not the spacing then what does the 2'-3" and 4'-6" signify on the top right side of the sheet in the Caltrans Bridge Design Specifications?

 

[bridgebuster]

http://www.dot.ca.gov/hq/esc/techpu...ridge-design-specifications/page/section3.pdf

 

[CivilStructural07]

I have the specifications already bridgebuster, but I don't know what the spacing is between the two rear axles for example. Or waht the 2'3" and 4'-6" means.

 

[bridgebuster]

forgot the rest. From the diagram it would appear that the loads are placed as shown for a particular vehicle. The 4'-6" looks like the out to out width of the last dolley, which is consistent with the rest of the sketch. Notice that the dimensions are given from the CL of the front axle.

 

[CivilStructural07]

What is the significance of the dimensions based off the front axle?

 

[bridgebuster]

Look at the sketch. The front axle is a single axle. The remaining loads are based on double axles. As a matter of simplicity, they assume that each double axle load acts a concentated load.

As I mentioned above 4'6" appears to be the out to out width of the double tires.

 

[CivilStructural07]

OK, thanks.

 

[bridgebuster]

no problem