Asphalt pavement bearing capacity

[twinnell]

I have been hired to confirm that a temporary trailer founded on steel stands will not punch through an asphalt pavement parking lot. Intuitively I would expect the bearing capacity of the asphalt concrete to be equal to or higher than the soil beneath, but I need backup to put in my calc. Can anyone tell me where I can find such information.

 

[eric1037]

Even if the "bearing capacity" of the asphalt is near or exceeds the soil, there will certainly be deformation of the asphalt when it heats up in the summer. I would plan on repairing the asphalt after the trailer is removed.

 

[twinnell]

The current foundation design calls for 8" concrete pads on soil. The owner wants to not use the concrete and just bear on the ashpalt. I have been asked to look into it to make sure that bearing on the ashpalt will work. Repairing the ashpalt after the trailer is removed is not a problem. I just want to make sure that the trailer doesn't topple over due to bearing failure.

 

[eric1037]

twinnell:

In your analysis, you should treat the asphalt like soil, not like concrete. Since you will be bearing directly on the surface (i.e. no embedment), there could be a bearing failure, not just settlement. You should take this into account in your analysis.

 

[csd72]

The asphalt is a super viscous liquid rather than a solid, and it will flow somewhat under constant load. This flow is more pronounced when it is hot.

It should be okay for a short period of time, but you need to explain to the client that this is not a predictable situation and that it may sink into the pavment over time.

 

[twinnell]

Just to fill everyone in; this is the response I got from a trustworthy local geotech:

Truck tires impart about 100psi (14.4ksf to the subgrade). An 18" plate at 4000psf gives you 9 kips per anchor. I don't see any problem putting it on the asphalt and softening shouldn't be an issue with that size plate. You may have to put a few helicals in to handle wind loads though.

Thanks for everyones response and I apologize for cross posting.