During construction using post-tension slab, a problem has required an extensive hole to be made in the slab.?

Question

The hole in the slab of new house construction will be about 30 x 3 feet in order to correct a problem with the slope of the sanitary drain. This hole will extend about a foot or so into the subsoil in order to remove drain pipe and re-grade the slope, then re-install/connect the drain pipe, backfill and replace concrete. The method of making the hole will involve cutting the concrete and chiselling around the post-tensioning cables. Should there be concern that the tension of the 30 foot span could cause the existing concrete to fail? How reliable of a concrete repair can be made so as not to effect the integrity of the slab? What other questions should I be asking the builder? Thanks for your ideas.

Answer 1

First I would ask if he has contacted your building Inspector for
approval to change the scope of construction from the approved
plans.
Has the contractor submitted a new plan for this work to the Bld.,
Dept.? Is the change d plan stamped by a Licensed Professional
Structural Engineer?.
The code specifically state: "The provisions of this code are not
intended to prevent the installation of any material or to prohibit any
design or method of construction not specifically prescribed by this code,provided that any such alternative has been approved".
This construction comes under the jurisdiction of your Building Official and must be approved by him/her before construction begins.
Protect yourself,contact your Building Official.
Good Luck

Answer 2

How did you determine where the problem is? How do you know it isn't out in the yard? I would send a camera through the drain to see what failed, and pin point where it is. Another thing.! Maybe the drain doesn't have to be removed. Why can't they reroute the drain, even at a shallower depth until it gets past the problem spot and then put a drop in it. this might solve your concern. Or route it out the side of the house and along it for thirty feet before tying back in.

Answer 3

For Christ sake don't cut the cables.
Personally, I'd find an alternative to digging up the slab. Re-routing the drainage would be the go if possible. Won't be so bad if you knew the exact location of the cables so as to avoid cutting them.

Hey, what a stuff up!!!!

Answer 4

ALL unfastened textile BE faraway from BREAKING BONDING AGENT utilized TO previous CONCRETE BEFOR POUR ( it may be extra beneficial TO observed cut back FLAT & DOWELL WITH REBAR ). COMPACT previous SOIL, conceal W PLASTIC, & RE - POUR! occurs each and every of the time, NO reason FOR ALARM. additionally SEE THAT THE PLASTIC SHEETHING remains IN TACK on the CABLES B-4 RE-POUR to guard THEM FROM CONCRETE!