DG & other similar surfaces

[jdfruit]

Wrestling with "firm, stable, and slip resistant" walking surfaces. Acres of "stabilized" DG type "paving" material used as walking surfaces, some is just installed, other areas a few years old, and some areas about 10 years old. Older surfaces (3 years and older) are starting to develop loose sand with oldest having localized areas building up to 1/4" sandy layer on top. Majority of surfaces are in "plaza" locations and about a thousand linear feet are directly adjacent to street sidewalks. These areas are used by thousands of people daily.

Need opinions on what conditions will require corrective work and what limits can be reasonably used to make the call for requiring corrective work. Issues are loose surface materials (sandy layer & vegetation debris) and deteriorating surface "flatness". I have looked at ACI for guidance and found the tolerances difficult for relation to maintaining this DG type material.

 

[mtlogcabin]

"firm, stable, and slip resistant" walking surfaces.

I do not find that in the code at all

 

[jdfruit]

From 2010 ADA

302 Floor or Ground Surfaces

302.1 General. Floor and ground surfaces shall be stable, firm, and slip resistant and shall comply with 302. ...

 

[mark handler]

http://www.stabilizersolutions.com/products/stabilized-decomposed-granite-and-crushed-stone/

Decomposed granite, with a binding agent, can form a firm, stable surface. Without the binding agent I would say Not compliant.

The problem is maintenance, time and weather.

Elements and wear and tear will break down the material making it NON-compliant.

 

[mark handler]

City of Austin TX

 

[jdfruit]

Anyone that deals with maintenance for "stabilized" DG have any input?

 

[ADAguy]

Have you spoken with the binder manufacturer to get their take?

 

[jdfruit]

Their take is rather biased; "our stuff is great" attitude, & "what's the problem?"

 

[Yikes]

Good research, Mark. I disagree with the City of Austin's / TAS interpretation of "stable"; in my opinion, it constitutes an overreach.

Just because something wears down over an extended period of time and needs to be occasionally fixed up, does not make it an unsuitable surface. I can think of plenty of instances in the code where components are subject to wear and tear:

- Painted striping on accessible stalls

- Rechargeable batteries in emergency lighting

- Roofing

- Heck there's a whole bunch of concrete sidewalk in our city that has buckled up due to the roots of parkway trees. Does that mean concrete is not a "stable" surface?

There are tests, such as ASTM F1951, that determine the stability of surfaces in play areas, or ASTM D4429 that confirm soils stability on roadway surfaces.

I think Texas has since updated their TAS to match ADA language of stable, firm, and slip resistant.

ADA also has this advisory:

Advisory 302.1 General.

A stable surface is one that remains unchanged by contaminants or applied force, so that when the contaminant or force is removed, the surface returns to its original condition.

A firm surface resists deformation by either indentations or particles moving on its surface.

A slip-resistant surface provides sufficient frictional counterforce to the forces exerted in walking to permit safe ambulation.

http://www.dustdr.com/decomposedgranitecasehistory.pdf

P.S. I can't believe I just said that code enforcement in Texas has gone too far. It's indeed become a cold day in hell.

 

[Wayne]

DG & other similar surfaces

We use stabilized DG here at the airport for access paths for maintenance vehicles and it holds up well for at least five years in our environment. It reminds me of pervious concrete.

 

[mark handler]

IMPO, It is a stretch to say Decomposed granite is a stable, firm, and slip resistant surface.

Even if stablized the DG can be unstable and can be "mud" when wet