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Vehicle Barriers Rule (was RE: Guard Rail)

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Wind and Earthquake scoot over and make room for the crashing car event with a higher probability and design load!

A barrier is required to catch the vehicle load 18" above the ground. Curbs don't do that. Street curbs are not a vehicle barrier to protect a building occupants and sidewalk pedestrians. The vehicle design force is higher than that of most shear walls for a small 2 story commercial wood building. It looks like the car threat is a big deal. Impact loads are first increased (doubled) then added to the live load "L" for the applicable load combinations.
The vehicle barrier live load is not treated, in the code, as an impact load. It appears to be only a live load. It is a live load that lasts less than 10 minutes, not an impact, and is the Live Load "L" in the load combinations.

Live load increase of allowable stress factor are only allowed for wood and for soil capacities in table 1804.2.

Clearly the code does not treat the vehicle crash as an impact load but the wood load category of "ten minutes" is not ruled out and so the wood allowed stress increase of 1.6 might be allowed.
IF the vehicle barrier load was WRONGLY considered as an impact load then the load should then be doubled (as for impact loads of ASCE 7-05 sec 4.7) Additionally: if the wood is pressure treated then the stress increase factor is not 2.0 but limited to 1.6 (ASD)

I had asked about a factor of 1.33. This is for a pole (bollard) cantilevered in soil IBC 1805.7.2.1 which references the soil table 1804.2. The note "d" permits a 1/3 increase for ASD wind or seismic. I see that the vehicle load is not wind or seismic and so not allowed for the vehicle barrier.
Is there a reference to allow a soil strength increase factor for a vehicle barrier?

David Merrick, SE
Sacramento


References:

NDS 2005 table 2.3.2 note 2. (limits stress increase factor to 1.6 or less for pressure treated)

ASCE 7-05  sec 4.4.3 "...Vehicle Barrier...6000 lb ... 1 ft 6 inch..." This is part of Ch4 "Live Loads" but not part of 4.7 "Impact Loads". Vehicle barrier loads are then not to be increased or doubled prior to being applied to the load combinations.

ASCE 7-05  sec 4.7 States that all live loads ie vehicle barriers are "assumed to include adequate allowance for ordinary impact conditions."

ASCE 7-05  sec 4.7 "Impact Loads"... increased by 100 percent..."


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