Fire engine wheel load
Fire engine wheel load
(OP)
To use the Westergaard equations to design slab on grade, I need to know for a fire engine weighing 75,000 pounds (maximum axle load = 27,000 pounds), what is:
- the number of wheels on the axle most heavily loaded
- the tire pressure
- the tire width
Can anyone help?
- the number of wheels on the axle most heavily loaded
- the tire pressure
- the tire width
Can anyone help?






RE: Fire engine wheel load
Tires will have a center-to-center distance of about 14 to 16 inches, so you will have overlapping wheel stresses.
Width of tire will be about 8 to 10 inches, depending on tire size.
Tire pressure would be 100 to 110.
RE: Fire engine wheel load
RE: Fire engine wheel load
If your truck truely weighs 75,000# it will have four axles. It will have a set of rear dual axles with a GAWR of 50,000, a pup axle and then a 20,000# front axle, I would guess. Tire pressure will bepend on the vehicle weight.
RE: Fire engine wheel load
Mike McCann
MMC Engineering
RE: Fire engine wheel load
so "the number of wheels on the axle most heavily loaded" ? ... well, pick a tire ... talk to a tire manufacturer.
and "the tire pressure, the tire width" ? ... see above (ie the tire manufacturer)
bear in mind you might not want to assume all the tire on the axle are equally effective ... 4 tires doesn't mean (IMHO) a tire load of 27000/4 = 6500 lbs; 'cause of non-uniformities ... grade, tire pressure, ...
so you might use 4 8000 lbs tires to support a 27000 lbs load.
Quando Omni Flunkus Moritati
RE: Fire engine wheel load
RE: Fire engine wheel load
RE: Fire engine wheel load
I will follow up with the fire department of the municipality where the building is located...in the meantime does anyone have a feel for the magnitude of the outrigger load?
RE: Fire engine wheel load
RE: Fire engine wheel load
RE: Fire engine wheel load
RE: Fire engine wheel load
"The stabilizer ground contact area for each foot pad shall be 10” x 14” without auxiliary pads
and 26” x 26” with auxiliary pads deployed. The ground pressure shall not exceed 75 psi with
auxiliary pads deployed when the apparatus is fully loaded and the aerial device is carrying its
rated capacity in every position. This shall be accomplished with the stabilizer pads deployed, as
outlined in NFPA 19.21.4.2."
http://www.e-one.com/sites/default/files/137551_sp...