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Cross Slope

P

Phil B

SAWHORSE
Joined
Sep 15, 2018
Messages
205
Location
Florida
I have a sloping section of walkway that can be easily achieved in under 5%. Its wide enough for 2 way traffic but not really wide enough for people to transverse diagonally. My question is at what width of running slope does cross slope click in? The cross slope on this would be over the allowable 2%. Thanks!

1746445605407.png
 
I don't think cross slope has anything to do with traversing diagonally.....It's slope perpendicular to the direction of normal travel I would say....
 
Yankee Chronicler said:
There is no width for cross slope to "click in." The slope is the incline in the direction of travel, and the cross-slope is the slope perpendicular to the direction of travel. Cross-slope on an accessible route is limited to 1:48.
Click to expand...
I'm talking about a situation where the primary path of travel is as shown below in green where the running slope is 5%, and the cross slope perpendicular to the green path is 0% . As a sloped space gets wider, and it's possible to traverse across the space like shown by the red arrow, the cross slope exceeds 2%. This wouldn't happen if this space was only 5' wide.

1746455378330.png
 

403.3​

The running slope of walking surfaces shall not be steeper than 1:20. The cross slope of a walking surface shall not be steeper than 1:48.

Don't measure it diagonally...
 
steveray said:

403.3​

The running slope of walking surfaces shall not be steeper than 1:20. The cross slope of a walking surface shall not be steeper than 1:48.
Click to expand...
Yes, I know. My question is that in the 1st sketch I posted, the running slope is under 5% but the cross slope could exceed 2%. Even though traversing at an angle to the running slope probably wouldn't happen because the pathway is narrow, would it be compliant? In the 2nd sketch, the space is wider where traversing across the main path is possible and the space clearly would not be compliant.
 
How about posting the actual site plan? If there is an actual direction of travel -- in other words, if this is a sidewalk rather than a terrace or patio where people might be walking in any direction -- then cross slope is measured perpendicular to the direction of travel. Just because someone can walk transverse to a sidewalk doesn't mean the code requires you to treat the cross-slope direction as a second path of travel.

As you have it shown in your second sketch, there is no cross-slope.

In your original sketch, at the top the cross-slope is 1" in 8'-6", or 1:112. That's less than 1%, and since there's no cross-slope at the foot of the walk, the cross-slope will gradually decrease from just under 1% to zero%.
 
Phil B said:
I have a sloping section of walkway that can be easily achieved in under 5%. Its wide enough for 2 way traffic but not really wide enough for people to transverse diagonally. My question is at what width of running slope does cross slope click in? The cross slope on this would be over the allowable 2%. Thanks!

View attachment 15576
Click to expand...
Hi Phil,
Here is what the 2010 ADA says.
"Advisory 405.3 Cross Slope. Cross slope is the slope of the surface perpendicular to the direction of travel. Cross slope is measured the same way as slope is measured (i.e., the rise over the run).
Phil, you need to measure the cross slope perpendicular to the direction of the path of travel. If the cross slope is greater than 1:48 or 2.1% it will not be in compliance with the ADA. I am assuming your up arrow is the direction of travel. I am showing that 8" divided by 19' = 3.5% running slope. The 8'6" with 1" difference in height is 0.09% nearly flat. I don't see what the elevations are on the edges of the 5'6" end so can't comment. By the way the recommended sample rate distance is each 24" running slope continuously and each 24" across for cross slope.
 
And here I was thinking it was an angry slope this whole time…I guess a better way to look at it is you are giving them a slope they can navigate properly or safely. If they move across the downslope, that is on them…
 
Jean Tessmer-HI said:
Hi Phil,
Here is what the 2010 ADA says.
"Advisory 405.3 Cross Slope. Cross slope is the slope of the surface perpendicular to the direction of travel. Cross slope is measured the same way as slope is measured (i.e., the rise over the run).
Phil, you need to measure the cross slope perpendicular to the direction of the path of travel. If the cross slope is greater than 1:48 or 2.1% it will not be in compliance with the ADA. I am assuming your up arrow is the direction of travel. I am showing that 8" divided by 19' = 3.5% running slope. The 8'6" with 1" difference in height is 0.09% nearly flat. I don't see what the elevations are on the edges of the 5'6" end so can't comment. By the way the recommended sample rate distance is each 24" running slope continuously and each 24" across for cross slope.
Click to expand...
What I am guarding against with respect to cross slopes is the situation where I have a large area at the top of sloping walkways leading to the access points of a building as sketched below.
Folks entering and exiting the building can walk in any direction in this area (highlighted in yellow) and therefore I believe all this area needs to be 2% max in any direction. Thank you all for your input!
1746545037230.png
 
Phil B said:
What I am guarding against with respect to cross slopes is the situation where I have a large area at the top of sloping walkways leading to the access points of a building as sketched below.
Folks entering and exiting the building can walk in any direction in this area (highlighted in yellow) and therefore I believe all this area needs to be 2% max in any direction. Thank you all for your input!
View attachment 15588
Click to expand...
I CAN walk on the grass...I won't enforce slope on it....
 
steveray said:
And here I was thinking it was an angry slope this whole time…I guess a better way to look at it is you are giving them a slope they can navigate properly or safely. If they move across the downslope, that is on them…
Click to expand...
Yes, this is correct. As a hypothetical, let's pretend that Phil B's site is 200' x 200', and there is only one meandering 4' wide pathway (in blue below) that provides <5% running slope, <2% cross slope, and at turns less than 2% in any directions to get you from one corner to another. Let's say it's not part of an access aisle in a parking lot. Maybe it's a wildly warping surface all over the place, like a skateboard park - - or what I see more often, a patio warping in many directions to a bunch of area drains.

Once you have provided the code-compliant pathway, there is no code requirement to further identify it with striping or any other markers. You could voluntarily stripe it out of the kindness of your heart, or as a "best practice", but otherwise the code leaves it up to the user to discern and navigate the accessible route that has been provided by the designer.


1746567842160.png
 
Phil B said:
What I am guarding against with respect to cross slopes is the situation where I have a large area at the top of sloping walkways leading to the access points of a building as sketched below.
Folks entering and exiting the building can walk in any direction in this area (highlighted in yellow) and therefore I believe all this area needs to be 2% max in any direction. Thank you all for your input!
View attachment 15588
Click to expand...
Hi Phil, I work with a large number of civil engineers. If they showed me the drawing above, my recommendation is attached. I hope this helps.
 

Attachments

Phil B said:
What I am guarding against with respect to cross slopes is the situation where I have a large area at the top of sloping walkways leading to the access points of a building as sketched below.
Folks entering and exiting the building can walk in any direction in this area (highlighted in yellow) and therefore I believe all this area needs to be 2% max in any direction. Thank you all for your input!
View attachment 15588
Click to expand...
I assume this is concrete if it is you can do touch corrections while the surface is still plastic to get to 100%. There is industry standard recommended flatness techniques that work and can still be done using standard industry techniques. The best to you. JT
 
Phil B said:
What I am guarding against with respect to cross slopes is the situation where I have a large area at the top of sloping walkways leading to the access points of a building as sketched below.
Folks entering and exiting the building can walk in any direction in this area (highlighted in yellow) and therefore I believe all this area needs to be 2% max in any direction. Thank you all for your input!
View attachment 15588
Click to expand...

What you have depicted here is not possible in real life. Think about it.

The interior floor is, presumably, flat (in theory, at least). Call it elevation 100.00. For simplicity, let's ignore any cross-or running slope on the landing areas immediately outside of each roor and call those all 100.00, too.

The upper and lower doors each have a level(-ish) landing and then a section of walk sloped at 4%. Let's say those sections are 4 feet in length. If the slope is 4%, the elevation at the foot of each of those (at the exterior face of the building) must be 99.84 - 100.00 minus 2 inches.

But the landing area outside the center door is also a nominal elevation of 100.00 for at least 5 feet in each direction. It appears (visually) that the distance from this landing area to the recesses for the other doors is about 2 feet to the bottom, and 4 feet to the top. The slab has to drop 2 inches in order to meet the foot of the sloped sections within the recesses. This means the one at the top will be roughly 4%, and the one at the bottom will be approximately 8%.

Why won't this work?

1747135411716.png
 
Yankee Chronicler said:
What you have depicted here is not possible in real life. Think about it.

The interior floor is, presumably, flat (in theory, at least). Call it elevation 100.00. For simplicity, let's ignore any cross-or running slope on the landing areas immediately outside of each roor and call those all 100.00, too.

The upper and lower doors each have a level(-ish) landing and then a section of walk sloped at 4%. Let's say those sections are 4 feet in length. If the slope is 4%, the elevation at the foot of each of those (at the exterior face of the building) must be 99.84 - 100.00 minus 2 inches.

But the landing area outside the center door is also a nominal elevation of 100.00 for at least 5 feet in each direction. It appears (visually) that the distance from this landing area to the recesses for the other doors is about 2 feet to the bottom, and 4 feet to the top. The slab has to drop 2 inches in order to meet the foot of the sloped sections within the recesses. This means the one at the top will be roughly 4%, and the one at the bottom will be approximately 8%.

Why won't this work?

View attachment 15636
Click to expand...
Thank you for looking at this! This is just a sketch - the real world version works, and the center door is 2" lower than the others.
 
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