AC Pavement Design for Fire Truck Loads

[dustycivil]

I have a fire marshall that is asking me to make sure my design of an AC roadway will handle the loads of a 70,000 fire truck. The road is an alley, so the pavement section is only 3 inches of AC over 4 or so inches of AB. I have had this question come up before, but I had a concrete pavement section. How do you design an AC roadway based on a Load not a TI and the R-valve of the soil?

 

[SlideRuleEra]

One option would be to use Structural Numbers (SN) for the various roadway components.

http://www.SlideRuleEra.net

 

[BigInch]

My sidewalk is thicker than that.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[dustycivil]

thanks, i am so used to the California Method for Pavement design, that I have never looked outside the box. I have found the design method using structural numbers.

 

[fattdad]

The problem with the SN approach for a limited use pavement design is you will calculate a pavement section that may not be "correct". How do you calculate an EAL for a 10 year design for incidental fire-truck use? I mean any properly designed automobile parking lot can handle one pass from a fire truck. What is likely to cause failure over time is lack of proper surface/ground water control. I'd say do you calculation (I don't know how many passes per year you'd reasonably expect or the pavement "life") and then focus on the drainage issue. If you have a poorly drained site - thicken the base or thicken the asphalt or do something to boulster the structural number.

Just a thought. . . .

f-d

 

[Ron]

Use elastic layer analysis for single vehicle applications that are not in the norm of traffic.

Remember that pavement design is fatigue based. Since fire use is infrequent, it would ultimately factor very little into a pavement design. It would have significantly less effect than say, a garbage truck.