Contact Us   |   Sign In   |   Register

Committee Log In

Download Final PDF

Interpretation #8175

Original Request

  • Date: October 24, 2018
  • Requested By: Jeff Arneson
  • Requester E-Mail: jeff@apextechnology.com
  • Code Version: 2017
  • Code: RESIDENT
  • Code Description:
  • Chapter:
  • Section: R403.1 (506.2.4)
  • Topic: Elimination of 36" strip of Welded Wire Fabric at edge of Footing

  • Question: Is it the intent of Section 506.2.4 that synthetic fiber in concrete slab allows for deletion of (2) rows 36" wide strips of WWF at Footing D of the attached drawing in section 403.1
  • Attachment 1: Footing D.pdf Download

Answer on 10/24/2018 at 11:35 AM

It is up to the design professional to determine if fiber mesh concrete can replace welded wire mesh. the Building code only provides minimums it is not a design manual. The intent of this section is to provide direction as to when the design professional can substitute mesh for wire at contraction joints.

Commentary:

The two methods are different. WWF is intended to hold the concrete together when there is cracking. Fibers are intended to prevent cracking and do little to hold the concrete together when cracks occur. There are fiber mixes that include different fibers allowing both functions to be satisfied. The double strip is for light frame construction that counts on the weight of the slab to resist uplift and overturning. The WWF is doubled to counter the tendency for thickened edge footings to crack at the juncture of the thickened edge and the slab. The FBC-R is intended to be a prescriptive document not requiring the input from a registered design professional. Deviation from the detail would require the input of a registered design professional. A combination fiber which prevents cracking and holds together when cracking does occur could be specified by a registered design professional.