Fire Truck Loading 2

[Wrightguy]

Could anyone give me some ideas on where I could find the AASHTO load cases or Gross Vehicle Weight of a Large (hook & ladder type) fire truck. I have to check the capacity of a parking garage to withstand this type of loading in the Kansas City, Missouri area.

Thanks ahead of time.

 

[jheidt2543]

How about checking with one of the fire truck manufacturers? I think Oshkosh Truck makes them. Try a search on the web.

 

[redhead]

Is there enough overhead clearance to allow access for a firetruck? Most parking garages are much too low!!!

 

[Qshake]

I agree with the first two comments. However, to answer the question, AASHTO doesn't have a list of truck specific loads. In general specific loads are left to each state, county or local agency to inventory and post ratings. From my experience on load rating bridges there are no specific weight/axle configurations in those guide specifications (National Bridge Inventory System or NBIS) for emergency vehicles such as fire trucks.

Your left to look up fire truck manufacturers on the internet and then contact them for more information.

I also can't believe that a fire truck could enter a garage nor that its Captain would allow a truck to enter a burning building or potentially burning building (assuming it was there for a car fire). It seems rather that the truck would be set aside the location and hose run from there as is typical for highrise structures.

 

[Ron]

Firetrucks and parking garages don't mix. None of the clearances work (vertical or turning radii). Loads are not really a big deal, since it is not likely that you'll have anything greater than 15 to 20 kips as a point load, and most garages are designed for 150 psf or so.

 

[redhead]

Ron:
Sorry to disagree, but a lot of us would be run out of business if we designed parking garages for 150psf. 50psf is all that is required by code.

 

[DaveVikingPE]

I had a similar assignment, though it was related to acceptable surcharge loadings next to a retaining wall...

Anyway, I found this to be a good resource:

http://www.firetrucks.com/antispam/pages/.

 

[LPPE]

I agree with redhead. 50psf for parking garages. Did a similar situation, and the firetruck loadng came to roughly 300 psf. Wouldnt you use the AASHTO HS-20 loading for firetrucks? Also, talk to your local precaster. They'll shed alot of light on truck loadings. Chances are you'll need precast beams at close spacing with a structural slab. Or you might want to try precast box bridge sections. They can handle the firetruck loading. If your parking garage T's are 44 inches deep, see what a precast box beam 44 inches deep will provide, and use them whereever the firetruck lanes are.
Sorry to ramble on!

 

[Wrightguy]

Thanks everyone. Great points to consider! I will be contacting truck manufacturers and getting their input. The parking garage in question can empty out at the top (street level). However, I also wondered why a firetruck would even venture into a garage with the WTC so close in our minds.

I knew this was the right place to post my questions!!!!

You guys (and gals) have been great. Thanks again.

 

[Ron]

Sorry guys...I should proofread and remove my typos. Thanks for pointing it out.

 

[MikeT14]

Wrightguy,

I am encountering the same situation with a garage design in OKC. The top floor of the garage empties out at street level on three sides of my garage. Luckily the architect/contractor/building inspector have agreed to deliniate a "fire lane" for the fire trucks so that I don't have to design the entire upper floor to support the load. Conversations with the local fire marshall stated that the design should be based on HS-20 highway loading.

I was just wondering what you ended up doing in your case?
Was your garage PT or precast?

 

[cap4000]

The Fire Truck is HS-20 Loads I think are per AASHTO. Without knowing your existing structural conditions and spans, I would start with a uniform live load of 300psf to 350psf as a cursory quick and dirty check. If that checks, then calc the lane and points loads from the axles. Good Luck.

 

[Wrightguy]

MikeT14,

The design ended up using AASHTO HS-20 and we intended on using precast. However, due to construction costs at the time, the project was scrubbed.

Thanks for your interest and again thank you everyone for your input.

Wrightguy

 

[mijowe]

In Northern Virgina some local governments have publilshed values for design, The largest truck weights range from 61 kips to 64 Kips, with a 30 Kip outrigger point load. They also list a minimum distributed load of at least 350 psf and as high as 450 psf.