Post-Tension Mistake?

(Dale Duffy) #1

New construction yesterday, they drilled through a post-tension cable.

PostTensionStamp.jpg

PostTension.jpg

PostTensionFailure1.jpg

(Jeffrey R. Pope, CMI) #2

What makes you think they hit the cable?

The third picture shows a cable that hasn't been trimmed. If it were severed, the wedges would have blown out the concrete (that's assuming that the cable had been stressed).

Here is a post showing damage from cables being severed. http://www.nachi.org/bbsystem/viewtopic.php?t=10052

(Dale Duffy) #3

Jeff,

The cable slide through the holding fastener. I'm going back next week and will take more pictures on the other side also.

The city wants the foundation repaired and re-certified now.

I thought the same thing or maybe they didn't tighten it. The framing contractor drilled all over the home which also called for re-certification of the slab in which the concrete contractor will not do....the building is on hold. And the buyers are pi$$ed-off.

(Jeffrey R. Pope, CMI) #4

Be careful how you report this. Use statements such as "appears to have," rather than definitive statements.

Cable failures are rarely "clean." They don't just slide, they snap (much like a rubber band). They are stressed to over 2500 psi and carry a substantial amount of kinetic energy.

(Dale Duffy) #5

Jeff,

I have a structural engineer who works for me. Which caused a stop work order from the city.

(Dale Duffy) #6

Jeff.

I was looking at the spools of cable, and they are not your average cable inside (sloppy plastic), the cables are tight to the plastic with just enough play to apply tension...odd

The city is not sure if they were even approved in Phoenix for this type of application.

(Jeffrey R. Pope, CMI) #7

Gotcha ;)

The tight fitting sheathing is actually the preferred standard (less void in the concrete).

I spent many years installing and stressing this type of cable. I also worked with "dry-strand" multi-cable & conduit systems which are grouted after stressing (used mostly in bridges and dams). I provided on-site training and quality control for this as well.

(Brian E. Kelly, AZ Cert. # 60234) #8

Dale, Jeff excellent thread. Dale let us know how this turns out. I have never seen a post tension cable failure and appreciate the info.:)

(NWJon) #9

"Cable failures are rarely "clean." They don't just slide, they snap (much like a rubber band). "

This is quite true... Several, many many years ago... I was but a wee lad, newbie carpenter and a post tension cable blew... It shot right thru into the house next door... Fortunately it was an unoccupied production home. Anyway, the master toilet room ended up having about 3 feet of cable sitting there in front of the commode.

Sheesh... could you imagine just sitting down to do some serious business...:shock: hehe... ROFLMAO! It definitely would have solved a constipation problem... ;) lol Anyway... forgive my rambling... this post just brought back some fun memories. Thanks guys!

Cheers,
Jon

(Jay Moge) #10

while i was in the navy we say training videos of what happens when "snap back" gets ya. in one the line from the dock to the ship was pulled so tight, it snapped, came strait back, and took the sailors legs OFF, not out OFF. they taught us tha best place to be is fa....fa, fa, away. the steel cable on the flight deck that the tail hook grabs is another snake to avoid.