Fire vehicle weight - LA County FC 503.2.3

[Yikes]

LA County Fire Code 503.2.3 requires fire apparatus access roads to support an apparatus weighing at least 75,000 lbs.
Question: does than mean I have to consider a point load of 75,000 lbs., or is it reasonably assumed to be distributed across several axles and wheels?

503.2.3 Surface
Facilities, buildings or portions of buildings hereafter constructed or moved into or within the jurisdiction shall be accessible to fire department apparatus by way of an approved fire apparatus access road that is designed and maintained with an asphalt, concrete or other approved driving surface capable of supporting the imposed load of fire apparatus weighing at least 75,000 pounds (34 050 kg). The fire apparatus access shall be surfaced so as to provide all-weather driving capabilities, as approved by the fire code official.

 

[Yankee Chronicler]

I would assume it's distributed, but then the question becomes HOW is it distributed? For a typical automobile, the weight has historically been roughly 60% on the front wheels and 40% on the rear wheels. For a fire truck, especially if it's a tanker, it probably has at least two rear axles, fairly close together, and more of the weight is probably on the rear axles than on the front axle.

And then there's the question of what the requirement is trying to accomplish. For something like a bridge span, the critical factor would probably be the total weight acting on the bridge at whatever the center of mass is for the truck. When discussing ground surface and pavement strength, then the actual load on each wheel becomes important.

 

[RLGA]

Most fire vehicles have a GVWR of 20,000 to 40,000 lbs. Aerial ladder trucks will have a GVWR close to 75,000 lbs; thus, I would assume the typical load distribution for this type of vehicle. If you cover this vehicle, you'll probably have sufficient load capacity for all other typical fire trucks.

 

[e hilton]

Question: does than mean I have to consider a point load of 75,000 lbs.,

Only if it’s a one-wheeled vehicle.

 

[mark handler]

LA Co Fire Code..503.2.3 Surface​

Facilities, buildings or portions of buildings hereafter constructed or moved into or within the jurisdiction shall be accessible to fire department apparatus by way of an approved fire apparatus access road that is designed and maintained with an asphalt, concrete or other approved driving surface capable of supporting the imposed load of fire apparatus weighing at least 75,000 pounds (34 050 kg). The fire apparatus access shall be surfaced so as to provide all-weather driving capabilities, as approved by the fire code official.
Exception: Regarding the weight rating, the fire code official shall be authorized to determine that fire apparatus access roads serving one- and two-family residences instead be capable of supporting the imposed load of fire apparatus weighing at least 50,000 pounds (22 700 kg).

 

[mark handler]

LA Co Fire Code..503.2.3 Surface​

Facilities, buildings or portions of buildings hereafter constructed or moved into or within the jurisdiction shall be accessible to fire department apparatus by way of an approved fire apparatus access road that is designed and maintained with an asphalt, concrete or other approved driving surface capable of supporting the imposed load of fire apparatus weighing at least 75,000 pounds (34 050 kg). The fire apparatus access shall be surfaced so as to provide all-weather driving capabilities, as approved by the fire code official.
Exception: Regarding the weight rating, the fire code official shall be authorized to determine that fire apparatus access roads serving one- and two-family residences instead be capable of supporting the imposed load of fire apparatus weighing at least 50,000 pounds (22 700 kg).

Standard fire engines: These commonly weigh between 20,000 and 40,000 pounds.
Larger trucks with aerial ladders: These can weigh significantly more, with some exceeding 70,000 pounds

 

[e hilton]

Anybody else seeing this?

 

[Yikes]

Anybody else seeing this?
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