Welded Wire Fabric 2

[DWHA]

I am the resident engineer on a job that has some 8" jointed pavement. The job specs call out for 6"x6" D8.0/D8.0 welded wire fabric to be used in the pavement. The contractor submitted an authorization to replace this with a double mat of 6"x6" D4.0/D4.0 welded wire fabric. Does this sound acceptable? What advantages and disadvantages to others see with this alternative. If allowed, should I require the two mats to be tied together?

 

[boo1]

4 wire is 0.225 Diameter
8 wire is 0.319 Diameter
50% smaller area which provides less effective crack control
flat work mats are typically lapped and tied together

look at link:

http://www.wirereinforcementinstitute.org/pages/pubs/pdf/TF 202-R-03.pdf

and

http://www.wirereinforcementinstitute.org/pages/pubs/pdf/WWR 500-R-08.pdf

 

[DWHA]

boo1,

You are comparing diameters, not areas. When you compare the areas they come out to be the same.

 

[RWF7437]

As a courtesy, wouldn't it be appropriate to ask the engineer who stamped and signed the plans you are working from ?

 

[weab]

If it is the same area and is only T&S steel, seems to me that this would be OK. I'd probably break into top and bottom layers, not together. Large aggregate may not work its way around, and development length may be affected but others may know better about that.

 

[Ron]

I'm not sure why a contractor would want to increase his labor to do this.

If done, I would separate the mats, putting one mat at 2/3 of thickness and one at 1/3 of thickness. That requires dropping mat on top of pre-placed concrete, as doing this and walking on the mats won't work.

 

[boo1]

my mistake i did not see "double mat"