AASHTO TRUCK LOADING

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owillis28

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HELP

What is the difference between HS-20 loading and HL-93 loading? What section in the AASHTO is it in? I haven't been able to purchase extra study material outside of what my company has due to financial constraints.

owillis

 
HELP
What is the difference between HS-20 loading and HL-93 loading? What section in the AASHTO is it in? I haven't been able to purchase extra study material outside of what my company has due to financial constraints.

owillis
My reference is the latest AASHTO LRFD code so the literal section numbers might be a little different from the test code (2003) but they should be close.

3.6.1.2.1 HL-93 is "the design truck OR design tandem" + "design lane load"

The design truck is an HS-20 truck (see section 3.6.1.2.2). The design tandem is two 25 k axles spaced 4 ft apart (see section 3.6.1.2.3).

The design lane load is 0.64 klf uniformly distributed in the logitudinal direction (see section 3.6.1.2.4).

Short answer is that to check an HL-93 load, one must consider the

combined load of the HS-20 truck with the lane load and also.

combined load of the tandem truck and the lane load.

Hope this helps.

 
Does this mean 1 and only 1 truck per span plus the lane loading? That is what I think but would like confirmation if anyone knows.

Cheers

Andy

 
Does this mean 1 and only 1 truck per span plus the lane loading? That is what I think but would like confirmation if anyone knows.Cheers

Andy
The spec is pretty detailed on how to apply the load. You need to consult it for your specific application. IF only one truck is used then a "multiple presence" factor of 1.2 is applied. Also, don't forget impact.

 
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