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Re: Handicap Wood Ramp Detail

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You wrote:

>I am working on a handicap ramp made of wood.  It has to have a maximum slope
>of 1:12 for ADA.  The question I have is how to detail the bottom of the ramp
>where it meets the ground.  Since the ramp has such a slight slope, the
>stringers die into the ground.  Let me illustrate.  If I have a 2x8 side
>stringer sloping down supporting the edge of deck it will be in contact (or
>have a taper cut) for 7 to 8 feet at the bottom of the ramp.
>
>How are wood ramps usually detailed at the base of the ramp to provide
>support, but I assume, no contact with the ground?  Is a long slab of
>concrete poured under it?

It seems more info is needed for an appropriate detail.  Is this an
exterior ramp?  Is the ramp being constructed over an existing walkway or
over soil?  What is the walkway constructed of?  Is the connecting walkway
being built with the ramp?

Assuming the ramp is built at the same time with the exterior concrete
walkway on grade, the wood ramp could be designed to abut the concrete edge
at a depressed surface with enough space for the ramp framing.

	                                  /<----ramp
	                                /
	_______________/
	                              |<---concrete edge
	                              |___________

This same detail could be applied to existing concrete walkway if a portion
the walk is replaced at the ramp edge with a depressed section.

Or the ramp can be constructed over an existing exterior concrete walk by
terminating the ramp stringer on a edge-beveled, treated plate anchored to
the concrete.  Assuming the use of treated 2x decking running perpendicular
the stringers and parallel the the ramp direction, the first deck 2x would
be back-beveled and nailed to the plate, then to the stringer.  Remember
the code allows 1/2 inch vertical change in the surface before the ramp
slope begins--I would recommend you use it.

+----------------------------------------------------------+
Ross E. Johnson, A.I.A. Architect  Id. #AR-1463
(208) 526-2431   org: 4130
E-mail address:	hns(--nospam--at)inel.gov
+----------------------------------------------------------+
Facility Engineering Unit  FAX(208) 526-2681
Mechanical, Civil, & Industrial Engineering Department
Lockheed Martin Idaho Technologies Co. (LMITCO)
Idaho National Engineering & Environmental Laboratory (INEEL)
Idaho Falls, Idaho 83415-3650
+----------------------------------------------------------+