| Author |
Message |
Anonymous
| | Posted on Thursday, September 25, 2008 - 12:09 pm: |    |
I hear these complaints on every multi-story job with post-tensioned floors and reinforced masonry infill - the masonry doesn’t line up with the floors, which doesn't line up with the frame, which doesn’t line up with the building lines—everything is so far out of alignment, that windows and doors, etc., cannot be installed and the building cannot be clad without major field modifications - stucco getting built out to unsafe thicknesses, its a never ending nightmare...blame it on poor construction, impossible schedules, lack of quality workmanship, sure, but is there a solution out there? What are you doing in your specifications to fight this problem? Is anyone listening? Does anyone care? |
William C. Pegues, FCSI, CCS
Senior Member
Username: wpegues
Post Number: 757
Registered: 10-2002
| | Posted on Thursday, September 25, 2008 - 12:20 pm: | |
Here in the DC Metro area, all high rise residential that we have done for say the past 10 years has been with PT slabs.
I am not sure what you mean by reinforced masonry infill. Reinforced masonry is an item of itself - grouted, vertical bars, etc.
If however you mean masonry facade tied back to metal stud walls, that's a lot of what we do. Also, metal panel.
We don't have the problem you mention.
Now - from time to time we do get a problem situation, but no complaint like that. And typically it is due to, and easily traceable to, really poor quality workmanship. Then its up to the Contractor to resolve.
But there has never been a complaint that it is not possible to do correctly, or that our tolerances are unreasonable.
And am I doing anything special? No, the post tensioned spec is one we have been using with numerous structural engineers for years with very little modifications over time, and none of them related to tolerances.
William |
Ralph Liebing, RA, CSI
Senior Member
Username: rliebing
Post Number: 907
Registered: 02-2003
| | Posted on Thursday, September 25, 2008 - 12:20 pm: | |
Yes, people-- many people-- care!!
And any specification includes parameters for quality and for how work is executed. Changed site conditions, and even reasonable tolerances in different work accumulate to create untenable results.
Observation, inspection and on-site quality control help, but must be diligent and must have the buy-in of all parties concerned and working.
In addition, there is little if any correlation and coordination between various materials-- e.g., many use 7-foot doors with 2" metal frame widths, and these do not align with normal brick coursing, creatng a "normal" and acceptable glitch and situation. Every material and system is not necessarily atuned to what may surround it--far too many possibilities-- they are deveoped in relative isolation.
Daunting task, but trying to get all of this to work together is a long-term effort and not fully resolvable in just the specs. |
Robert W. Johnson
Senior Member
Username: bob_johnson
Post Number: 180
Registered: 08-2004
| | Posted on Thursday, September 25, 2008 - 12:30 pm: | |
Ditto Willam's experience with that almost exclusively used type of construction in the DC metro area for high rise residential construction. |
Russell W. Wood, CSI, CCS
Senior Member
Username: woodr5678
Post Number: 123
Registered: 11-2003
| | Posted on Thursday, September 25, 2008 - 01:54 pm: | |
What you describe sounds like typical South Florida construction. Obviously, we don't specify it that way...it's all up to policing of the contractor and construction. However, everything is relative. Reminds me of a large hotel/offices/shopping center project we had in Cancun Mexico back in the 80's. The construction progress photos we received here the states showed daylight coming through voids in the block work of up to 1/2-1 inch dia. We said this is unacceptable...the local CM said that actually this was pretty good construction quality for Mexico. |
Nathan Woods, CCCA, LEED AP
Senior Member
Username: nwoods
Post Number: 273
Registered: 08-2005
| | Posted on Thursday, September 25, 2008 - 01:58 pm: | |
"the local CM said that actually this was pretty good construction quality for Mexico."
Perhaps you should reference the Aztec or Maya ruins as acceptable mock-ups for masonry construction workmanship standards :-) |
William C. Pegues, FCSI, CCS
Senior Member
Username: wpegues
Post Number: 758
Registered: 10-2002
| | Posted on Thursday, September 25, 2008 - 01:58 pm: | |
"We said this is unacceptable...the local CM said that actually this was pretty good..."
After all, what do you think calk was invented for anyway -grin!
William |
Don Harris CSI, CCS, CCCA, AIA
Senior Member
Username: don_harris
Post Number: 208
Registered: 03-2003
| | Posted on Thursday, September 25, 2008 - 02:10 pm: | |
Biggest problems we have with PT concrete is having to core drill the slab after the fact. 100% coordination is darn near impossible. Other than that and the occasional oops, our experience has been similar to William's. |
Russell W. Wood, CSI, CCS
Senior Member
Username: woodr5678
Post Number: 124
Registered: 11-2003
| | Posted on Thursday, September 25, 2008 - 02:11 pm: | |
I think that's what they said. We did all the drawings & specs in metric system and Spanish with an interpreter. I've forgotten...how do you say "5/8" stucco on metal lath" in Spanish? |
John Bunzick, CCS, CCCA, LEED AP
Senior Member
Username: bunzick
Post Number: 967
Registered: 03-2002
| | Posted on Thursday, September 25, 2008 - 06:29 pm: | |
Tal vez se dice "estuco sobre listón de metal, 16 mm." ¿Verdad? |
Russell W. Wood, CSI, CCS
Senior Member
Username: woodr5678
Post Number: 125
Registered: 11-2003
| | Posted on Friday, September 26, 2008 - 08:32 am: | |
By George, I think you've got it! |
Mark Gilligan SE, CSI
Senior Member
Username: mark_gilligan
Post Number: 94
Registered: 10-2007
| | Posted on Monday, September 29, 2008 - 02:42 am: | |
You should be able to prevent these problems if you can answer the following questions.
What are the tolerances for individual systems (ie concrete and the skin)?
Can tolerances be realistically achieved? For concrete I would start with ACI 117.
What are realistic tolerances between the in-fill CMU and the concrete? Are they acceptable or do you need to modify your details?
If you can answer the above questions then the question is will the contractor make the effort to build it as required? Early in the project specify inspections to verify work is in conformance with the tolerances. |
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