I have a contractor who after casting a foundation realised that the starter bars for a column were mislocated , so the starter bars were cut and new bars were drilled and grouted in the correct location, since then this issue has been repeated frequently on other foundations and is becoming quite normal. there is nothing in the contract that says he cant do it. is there any code requirment thatthe steel MUST be cast in the concrete or dos any one have a strong argument i can use against him such that the foundation to be re-done?
Eng-Tips is the largest engineering community on the Internet
Intelligent Work Forums for Engineering Professionals
-
Congratulations waross on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
grouting of re-bar 5
- Thread starter JECCNC
- Start date
-
1
- #2
This is a common problem.
Cast-in anchors will give a greater pull-out capacity but they are frequently misplaced on-site. This leads to the contractor preferring post-installed chemical anchors. The problem with this is that the epoxy anchors are generally not installed properly which gives less capacity particularly in tension. If the columns are required to take uplift loads, I would specify that a minimum of 10% of the anchors to be load tested. It should not be a problem if the column has not been erected. I had a thread about this problem recently. Preferably call-up a mechanical anchor is the column works in tension.
thread507-257487
Cast-in anchors will give a greater pull-out capacity but they are frequently misplaced on-site. This leads to the contractor preferring post-installed chemical anchors. The problem with this is that the epoxy anchors are generally not installed properly which gives less capacity particularly in tension. If the columns are required to take uplift loads, I would specify that a minimum of 10% of the anchors to be load tested. It should not be a problem if the column has not been erected. I had a thread about this problem recently. Preferably call-up a mechanical anchor is the column works in tension.
thread507-257487
-
1
- #3
It may be argued that the solution provided as substitute is entirely altogether different of what designed. However with no advertence in the design and contract documents enforcement of making again the foundation on just this issue is seen upon custom as unwarranted, since the solution provided seems to work, they can warrant that stands in both tension and compression the allocated forces and this means that if using a propietary system, stress transfer to the concrete is usually accepted be O.K.
-
1
- #4
-
1
- #5
I agree with Ron - epoxy!
Nothing to prevent him from doing this? I don't know about that. The drawings ARE contract documents. I don't know your specific contract, but generally he is required to install as indicated on drawings. However problems come up. When he is unable to install as indicated, I would think he needs owner approval for a fix.
I would think that you are entitled to cut sheets which indicate the strength of what he is doing and whether or not he is installing correctly. You should determine if this is suffient. There are different epoxy systems with different strengths. Please verify! I hope he is not charging you for this extra work.
You could have an inspector on the job before any pour to make sure that the bars are installed correctly. In lieu of that, maybe you could have a meeting with him indicating that you are unhappy with the quality of work and have him explain to you how he intends to increase quality.
In the end, epoxy anchors are usually sufficient. If so, allow it.
Nothing to prevent him from doing this? I don't know about that. The drawings ARE contract documents. I don't know your specific contract, but generally he is required to install as indicated on drawings. However problems come up. When he is unable to install as indicated, I would think he needs owner approval for a fix.
I would think that you are entitled to cut sheets which indicate the strength of what he is doing and whether or not he is installing correctly. You should determine if this is suffient. There are different epoxy systems with different strengths. Please verify! I hope he is not charging you for this extra work.
You could have an inspector on the job before any pour to make sure that the bars are installed correctly. In lieu of that, maybe you could have a meeting with him indicating that you are unhappy with the quality of work and have him explain to you how he intends to increase quality.
In the end, epoxy anchors are usually sufficient. If so, allow it.
Find the "Professional's Guide on Grouting and Concrete Repair" at the site below. According to Five Star, cementitious grout is recommended for rebar grouting under static loads, depending on the application.
-
1
- #7
boffintech
Civil/Environmental
JECCNC, take it from a full-time on-site inspector if you want to get an idea of if these bars were drilled/epoxied semi-correctly, upon your next site visit try this: upon arrival skip the initial trailer visit and go straight to the construction area, locate the labor who drills/epoxies the bars and ask him to show you the drill bit and the BRUSH used to clean the hole.
If he says, "What brush?" you have your answer: installation worthless; drilled holes not cleaned out correctly resulting in insufficient bond.
If he shows you the drill bit and it's the incorrect diameter: installation worthless.
Next ask to see the devise used to BLOW OUT the brushed holes with OIL FREE air. If he points to one of those big trailer mounted air compressors you have your answer. Those things do not filter the air and consequently blow out oil with the air so the inside of your hole could be coated with a bond breaker. Yikes!
Consider having a testing lab perform a few pull-out tests.
If he says, "What brush?" you have your answer: installation worthless; drilled holes not cleaned out correctly resulting in insufficient bond.
If he shows you the drill bit and it's the incorrect diameter: installation worthless.
Next ask to see the devise used to BLOW OUT the brushed holes with OIL FREE air. If he points to one of those big trailer mounted air compressors you have your answer. Those things do not filter the air and consequently blow out oil with the air so the inside of your hole could be coated with a bond breaker. Yikes!
Consider having a testing lab perform a few pull-out tests.
racookpe1978
Nuclear
If pull-out load is a criteria for those columns, get a load test done as recommended above on 10% of the "grouted" (I also doubt he used epoxy.)
If one fails, do 20% of the remainder. If the bolts/anchors are failing, you MUST replace them. Too often, the contractor assumes that "obviously the entire load on the anchors is straight down because the building weight is straight down so if the bolts are "stiff" and in the holes of the column bases, then all is OK".
Not so. Good advice above. Make sure the contractor pays for the testing - it was HIS work that required the bad ancchors to be cut out and moved!
If one fails, do 20% of the remainder. If the bolts/anchors are failing, you MUST replace them. Too often, the contractor assumes that "obviously the entire load on the anchors is straight down because the building weight is straight down so if the bolts are "stiff" and in the holes of the column bases, then all is OK".
Not so. Good advice above. Make sure the contractor pays for the testing - it was HIS work that required the bad ancchors to be cut out and moved!
- Status
Similar threads
- Locked
- Question
- Locked
- Question
- Locked
- Question
- Question