Accessible Ramps - 2% Slope In Any Direction 1

[Matewan]

I've never really had a solid conviction on this, so I though that I'd get some opinions from some other site/civil folks working in the USA (or anywhere else, for that matter)...

ADA Standards and various building codes state that ramp landings shall not have a slope steeper that 2-percent in any direction. Accessible parking spaces also have similar wording. So, my question is this: Does that mean that the (two) cross slopes can be no greater than 2-percent, or does this really mean no greater than 2-percent in any direction? For a number of years now, I have taken a conservative approach and tried to design my ramp landings (or accessible parking spaces) so that the hypotenuse, if you will, of the cross slopes is a maximum of 2-percent (e.g. a 1.4-percent cross slope in either direction). There are times, however, when it sure would be nice to squeeze a little more elevation out of my designs.

How do others handle this? Thanks in advance.

 

[NCSUBOY74]

A reviewer, who is the HC guru says and reviews it in all directions, this is also the way the inspectors for low income housing review it. More than 1 space has been repaved due to this approach.

 

[civilman72]

I agree. 2% in ANY direction.

Promotes birdbaths --> failing asphalt, but there is generally no flexibility in the code.

 

[Twinkie]

ANY direction to be ADA compliant. Your hypotenuse approach is correct.

 

[IRstuff]

I think the OP was saying that his design was more stringent than the standard.

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[LincolnPE]

No he's actually pushing it as far as he can..the resultant vector cannot exceed 1:48 (2.08%)

Use concrete for the spaces to mitigate ponding.

 

[MrBachelor]

Agreed, 1:48 is the real limit. The standard really is ANY direction. Slopes in both directions can get complicated in construction so it's best to keep the design flat in one direction and 1.75-1.85% the other way for construction tolerance considerations.

A laser level can be laid in any direction to check the slope, not just N/S E/W.

Nate the Great

http://www.ceieng.com

 

[darthsoilsguy2]

The other quirk to this... is the gray area about designing a 5% walk with a 2% cross slope because it creates a diagonal 5.4% ramp with no landing.

 

[LincolnPE]

Nice try Darth...The criterion for sidewalks is 1:48 perpendicular to the path of travel (cross slope)..

 

[darthsoilsguy2]

i've had to redesign because somebody on a town design review board with a scale bar saw my 1' contours were a little closer than 5' spaced and interpreted "path of travel" to not exclude a chair correcting their path on a 5' walk.... so... i'm sticking to my 'gray area' guns.

 

[LincolnPE]

Sorry there is no gray area here..the 5% grade criterion is measured along the path of travel.

 

[brandonbw]

I keep anything ADA at 2% and under in all directions. The story when I first started working about ripping out an entire parking lot because the ADA crew comes to check new construction at random made me never forget. Sue happy people out here.

The thing I can't stand is redoing a crosswalk ramp at the bottom of a steep sidewalk. The end result around here can be a more steep ramp.

B+W Engineering and Design | Los Angeles Civil Engineer and Structural Engineer

http://bwengr.com

 

[LincolnPE]

Not everything has to be less that 2% in all directions..You have ADA compliant ramps for example.

The 2% in all directions only applies to landings and parking spaces.

 

[brandonbw]

OP was talking about landings. I hope we know the different rules for ramps.

B+W Engineering and Design | Los Angeles Civil Engineer and Structural Engineer

http://bwengr.com

 

[Matewan]

Thanks to all who have taken the time to reply.

One of the things that precipitated this thread was that I was designing a parallel curb ramp for a sidewalk adjacent to a school access road - a road not in the public right-of-way. The FHWA publication entitled "Designing Sidewalks and Trails for Access" states that "the installed slope of the gutter around the base of the curb ramp should be a minimum of 0.5 percent" since poor drainage at the bottom of a curb ramp is inconvenient and can result in the accumulation of debris or (in cold-weather locations) slush and ice. The same publication also states that the drainage slope of the gutter (i.e. the slope parallel to the curb and roadway) should not exceed 2 percent, and has several illustrations that depict the landing of a parallel curb ramp sloping towards the street at 2 percent. Putting two and two together (or, should I say, 2 percent and 2 percent), this would mean that the maximum slope of the landing in any direction would actually be 2.8 percent.

Now, I know that this is a curb ramp and not an accessible parking space or a ramp leading into a building. But the same drainage challenges exist for those situations and it just seems that, from a "big picture" perspective, the intent of the code for ramp landings and accessible parking spaces would mean that the cross-slopes can be no greater than 2 percent. Unfortunately, I fear that many inspectors would not be so broad-minded; hence the dilemma...