Fire Truck loading using AASHTO LRFD 2

[hsustersic]

There are a number of older threads on the topic of fire truck loading on this site. None of these seem to reflect the HL-93 notional live load model currently used for bridge design under AASHTO LRFD.

I have an underground parking garage which will have a fire truck access lane at the highest (grade) level. For the access lane support structure, I wonder whether the HL-93 loading is appropriate for this condition... or should I do some research including fire truck manufacturers as suggested by previous threads?

Thanks.

 

[SteelPE]

Please note that I am not a bridge guy and have only a very small familiarity with the AASHTO code (enough knowledge to pass the PE exam).

I faced a similar problem a few years ago. You probably came across it in one of my threads. I struggled with the problem for quite some time. I called a mfr. only to find out that they design their outrigger pads, which were 24” x 24” at the time, for 100 psi (I think). In the end I ended up using loading that was represented by the City of Denver building code which can be found here:

http://www.denvergov.org/Portals/646/documents/buildingcodes/DBC2008.pdf

If you go to page 68, you will find the loading they recommend specifically for fire trucks. It is the only code that I have seen that specifically gives you the loads you are to design for.

Does this fit your application… you will have to decide.

 

[lkjh345]

Excellent Post SteelPE. We have found this outrigger criteria to be the controling load case in some instances as well. Like you, we found this in the Denver Building Code, but choose to apply it to conditions where a fire truck could be on top of our structure in other cities/states.

 

[msquared48]

I have seen some outrigger loads in the range of 7 to 800 psi and posted in another string the details. Utterly ridiculous.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask