Small Radius Hadicap ramps? 3

[CivAlan]

In the small town that I am City Engineer in, we have a lot of older neighborhoods that 5' radius corners. We have a grant to install sidewalk in some of these areas. However, he grant does not include money for purchase of additional right-of-way. Because it is federal funds, we have to install handicap ramps on the corners where we are installing new sidewalk.

Has anyone seen a design for a handicap ramp that meets ADA requirement for small radius corners? If so, where can I get a look at it?
Thanks,
C. Alan

 

[Ron]

Since your are concerned with the radius of the corner and its affect on the available width of the sidewalk, why not turn the entire corner into a ramp, both directions?

 

[gibfrog]

Check out your local DOT standard indexes. Although I feel that a minor modification Ron's solution might be the best aolution. Now in Florida, we usually have atleast a couple of feet as a flat pseudo landing for the wheel chair to stop before entering the crosswalk on the roadway. This flat area in in line with the crosswalk. If you have two crosswalks at 90 degrees, the whole area between them could be flat also. (Flat being under 2% max slope.) You can order the Florida DOT standard indexes, they are under $20 but your state or your neighboring states should have something simmilar.

Clifford H Laubstein
FL PE 58662

 

[gtrainor]

Cuttin the whole radius is probably the best answer just as RON and Gibfrog suggest. Though more expensive than the Florida DOT, is the California Disabled Accesibility Design Guidebook, known as CALDAG. This book meets or exceeds all ADA and is easy to read and understand.

http://www.buildersbooksource.com/cgi-bin/booksite/20010.html

If you post your fax #, I will send you a drawing out of CALDAG that might work.

 

[GeoPaveTraffic]

You should check out

http://www.access-board.gov

and look for a pdf file titled PROWguide. It contains many concept type drawings showing how to get ramps to work under different conditions. It also contains information on why certain items are included in the standard design, which is a big help if you need to modify the standard design.

By the way, it does not matter if federal funds are involved, any time work is done on street or sidewalk a compliant handicap ramp must be installed. There is no option. The city were I work is installing about 130 new ramps this year.

 

[KThomson]

GeoPave -

Thanks! That publication is great. Just yesterday, I was in a meeting with a town engineer and we were discussing handicapped ramps. In his experience, the typical details we tend to cut and paste aren't constructed to be code-compliant. He had great solutions for the design - and there are even more in that publication. Also, the report has photos and sketches, which make things much clearer than what is shown in the ADA regs.

Thanks for the great tip!

Kate

 

[CivAlan]

GeoDave,
That publication looks great. I did find a CALTRANS standard ramp that looks like I could modify it to go on a corner. The ramps are here:

http://www.dot.ca.gov/hq/esc/oe/project_plans/highway_plans/stdplans_metric_99/viewable_pdf/a88a.pdf

I am dealing with Case 'c'. I have no avalible ROW behind the corner, so the normal 4' landing behind the ramp is not possible. This ramp design appears to meet the ADA requirments. It has the 8.33% max slope, but this tends to make for very long approach ramps. I think that if I bump the maximum slope up to 9.00% I still will be in within the design peramiters.

gtrainor: My fax# is 661 758 7239 I would love to take a look a the CALDAG design.

Thanks, C. Alan

 

[CivAlan]

I have come up with a design. You can see it here:

http://www.pbase.com/caw18/ramp_design

Comments are welcome.
Thanks,
C. Alan

 

[ACtrafficengr]

If you have a conveniently located drop inlet on the up-hill side of the corner, consider a bulbout to get more room. This will allow pedestrians to wait for gaps out past the parking lane where they are more visible, and you can probably squeeze in a 10 - 15' radius, depending on the width of the parking lane.

Comments on your design:

The tactile surfaces should have the long dimension parallel to the crosswalk. Angling them like that may lead blind pedestrians to cross diagonally into the middle of the intersection.

The bottom of the ramp will leave wheelchairs up on two wheels, and make them want to rock. Disconcerting and difficult for the user.

 

[gtrainor]

CAlan, I've just faxed 3 pages to you from CALDAG. Let me know if it helps.

 

[CivAlan]

Thanks gtrainor, I got the fax.

It looks like I should put the 8.33% slopes back in.

If the truncated dome surface section should be parallel to traffic, where on the design shoud the truncated surface be?

Thanks,
--C. Alan

 

[gtrainor]

Alan, unless you are in California, I would forget about the truncated domes. I have faxed you the authors interpretation in where he recommends not using them. The domes are probably being realized as an "overkill" item.

 

[GeoPaveTraffic]

gtrainor, unless you want to be in direct violation of the ADA, you must install the truncated domes. The moratorium on the domes expired in 2001 and the are now required.

 

[gtrainor]

I stand corrected, thank you Geo... CAlan, I would look at:

http://www.fhwa.dot.gov/environment/bikeped/dwm.htm

 

[CivAlan]

Well, I happen to be in california. If I am reading 4.7.7 correctly, then the entire surface that is sloped 8.33% will need to be truncated. At least that is what the design gtrainor sent me indicates. The new ramp design is here:

http://www.pbase.com/caw18/ramp_design

Thanks for your help!
-C. Alan

 

[CadAndy]

CivAlan,

I have a few questions about your design. I designed
a few parking lots and we where told that ADA could only
be 2% Maximum.
1) If this is so, why do you have 8.33% in the
two corners?
2) Shouldn't the grade from 2% to 8% be a gradual
increase it looks like a retaining wall might be
required along the sidewalk.
Are designs for sidewalks and parking lots could not
exceed 3.5% unless we had a manhole near a steep grade.
Can you please clarify. I am kinda new in this
department.

 

[gtrainor]

CADANDY, the 8.33% slope is allowed only on the ramps (short distances) not a sustained run.

C Alan, your design looks fine to me. But there is still some question about the domes being even in the flat section. It seems that there is some contradiction in the CalDag. Please see the lower note on fig 28. It states that domes are still needed on the flat area if adjoined to vehicular traffic. I don't know what that means. You may want to consult with ADA directly.

 

[CivAlan]

Thanks for the help and faxes gtrainor. I have about 3 weeks to get this project wrapped up and into the county for approval (it is CDBG funded). So I will try to contact ADA soon. I was under the impression that the domes needed to be perpendicular to the traveled way.

CadAndy:
I think the 8.33% slopes are allowed on handicap ramps because of the limited space avalible in the street right-of-way. Most streets have 6" curbs, and the corner areas are limited.

Yes, I am going to have to put in a retaining curb along the backside of the sidewalk.

Ideally, the transition from 8.33% to 2% should be gradual, however, the use of the truncated domes may make this difficult. That stuff is rigid plastic.

 

[CadAndy]

CivAlan and gtrainor

Thanks guys. Its always good to get
other ideas on different designs.