How to read bar grating tables

The HL-93 16 kip wheel load is applied to a contact area that is 10" long and 20" wide. Assuming the direction of travel of the wheel across the grate is not defined, or not limited, I think you would apply the 16 kips across 10" of grate perpendicular to the span of the main bars in the grate, divide the 16 kips by the number of bars within the 10", and then spread the load on one bar along the bar as a uniform load that is 20" wide. That will give you a fairly conservative estimate of the moment on the bar.

That would be the hard way, and probably very conservative, because it doesn't account for any distribution of load to other bars in the grate. I couldn't get your link to work, but I would be very surprised if you contacted the supplier, and they were not able to tell you the max span for their grates would be subjected to HL-93 loading.




Rod Smith, P.E., The artist formerly known as HotRod10

The procedure that BridgeSmith lays out is how I understand the footnotes in the load tables that Brown-Campbell use for truck loads: LINK

Please note that is a "v" (as in Violin) not a "y".

Grating Pacific has some good info on their website regarding the design criteria and load tables for traffic rated grating.

If you look at the span table in winelandv's link, the far right column shows the clear span limits for an H-20 truck, which has the same wheel load as an HS-20 and HL-93.

As I look at the table posted by GC_Hopi, I realize I didn't include the increase for Impact (30%), making the load for design 20.8 kips.

Rod Smith, P.E., The artist formerly known as HotRod10