We specify that the geotextile under riprap must be nonwoven, needle-punched, Class 1. NCHRP Report 568 (page C-25, Section 7.1) requires that nonwoven geotextile filter under riprap must have a mass density greater than 12osy (ounces per square yard).
We have the following questions:
- What is the cost difference between nonwoven needle-punched, Class 1
12osy vs. nonwoven needle-punched, Class 1 8osy?
- Is nonwoven needle-punched, Class 1, 12osy considered “special order”?
- Is nonwoven needle-punched, Class 1, 12osy available in the state of Nevada (local suppliers)?
- Does nonwoven, needle-punched, Class 1, 12osy require longer delivery time after ordering if it is considered “special order” that might cause construction delay?
Basil | India
Thanks for your questions in which the following apply:
- Cost is approximately proportional to the weight. Thus, a 12osy will cost about 50% more than an 8osy geotextile.
- Needle-punched nonwovens in the range of 4 to 16osy are standard products.
- I certainly hope so since it is a standard product. The only comment that I add is if the project is extremely large a given supplier might have to order more from a manufacturer.
- Delivery times should be short since this is not a specialty fabric. Again, if the order is huge there might be a time delay.
Good luck with your project.
Bob Koerner | GMA Techline