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Talisker2
Registered Users
Posts:11
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| 10/18/2007 4:47 PM |
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I am really new to this discussion forums and just finished reading Ian Giesler's article about the wonders of "VertiForce Fibers" he mentions a lot of pluses for this product in the vertical wall, about how much less steel is required and how much easier it is to consolidate etc.
I have a few questions for anyone who has used this. How much fiber to add per yard, what was the psi of the mix and how well was it accepted by the building inspector.
I have no doubt it is easier to work with and much faster way to complete the wall pour. I live in a seismically active area and wonder how a engineer would plan a wall to determine how much additional steel is still required. Is there some kind of table that will say for x amount of fiber per yard x amount of steel is not required?
Does this product live up to its claims and can they be quantified?
Thanks
Jim |
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lkazanov2
Registered Users
Posts:108
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| 10/18/2007 7:39 PM |
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Jim,
This is very interesting technology. I am also interested in this product. As you have discovered, all ICF are essentially the same in the end result (ie, 6" concrete with 2.5" foam either side). It is how you get there to a solid, plum, and square wall is the question. As the forums indicate the key to ICF is the pour and consolidation. There is a very indepth thread on this. I believe that vertiforce use will increase if the acceptance to ICF's in general continues to increase.
Leonard
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dmaceld
Registered Users
Posts:469
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| 10/18/2007 9:03 PM |
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VertiForce is now Novomesh 700. Go to link where you'll find more info. I suspect the limit on wall height (see brochure extract below), the relatively limited reduction in required rebar, and the mix use, 2 bags per yard, probably make it not sufficiently economical to use. It may actually add cost. I image the best use is in seismic and hurricane areas where you can increase wall strength without going thicker. It looks to me like it may be an expensive solution to a low cost problem.
GUIDELINES
Novomesh 700 fibers should not be used to replace structural, loadbearing
reinforcement. Novomesh 700 fibers should not be used as
a means of using thinner concrete sections than original design.
Novomesh 700 is acceptable to use assuming your wall is a simply
supported wall, has a minimum wall thickness of 4 in and a
maximum height of 8 ft or has a minimum wall thickness of 6 in
and maximum height of 10 ft, and a concrete compressive strength
of no less than 3,000 psi.
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Building house - what a way to spend retirement! |
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dmaceld
Registered Users
Posts:469
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Talisker2
Registered Users
Posts:11
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| 10/19/2007 10:56 AM |
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Thanks guys for the quick response. At this time I am looking at possibly (because we still are not firmed up on the plans) but ideally if I can do it is to have 8" basement walls with first floor of 6" and second story of 4" allowing a brick ledge turned in on each. I will have to run some numbers to see if this is doable. In some respects it is overkill but we live about 2 miles from Castle Mountain fault and I would feel more comfortable to over build for that eventuality.
I plan on working with my builder and hopefully he will be more knowledgeable than me on the reinforcing requirements. I feel that a few K in overbuild of concrete, steel and fiber mesh is going to be money well spent. Basement will depend on ground water issues and until I get a soils test next year I will be just speculating on if I go with a basement or FPSF (frost protected shallow foundation). Ideally I would like to have a 10' basement so I can have plenty of room for the mechanical's and still allow enough room to have a wood shop down there. I am planning on pouring concrete floors on all three if practical. Concrete on the main floor would isolate most of the noise from the shop and also make it much more fireproof. |
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Ian with ICF Builders
Posts:0
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| 11/05/2007 10:14 PM |
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Vertiforce or Novomesh is still a viable product. I'm glad to see that the many experts on ICFWEB have done research and worked with engineers and incorporated products such as this into ICF walls. I believe this is why we have specified products such as Novomesh 700 in multistory buildings, replacing horizontal #4 bar at 16" on center and #5 bar at 12" on center vertically and essentially cut reinforcing steel requirements by70%. We have not only done so, but we have done so with a small material cost savings by incorporating the Novomesh product. What we are happy about is that there are so many experts in the ICF field that think that we are "more expensive alternative", so much so that we give 50% of the labor savings back to the developer and add the other 50% to our bottom line.......In short, My suggestion to folks that don't know much ought to not say much because the expert opinions do more damage to the entire ICF industry as a whole than they realize. I find the phone call or copied email of topics like this humorous.....another idiot casting doubt in the minds of the very people they think they are converting to ICF......yet the idiot is the very reason people stay away from ICF......some idiots must get their income from other sources...perhaps they are really on a mission to quell the use of ICF??
This one figured last week, We removed 30k in reinforcing, replaced it at 50.00 per yard upcharge for a 27k total increase in concrete cost. Net is 10% savings in material, labor savings equals total of 6 days on this project, again, about a 10% savings....we keep 50% of savings....they keep 50%. Our crew is happy because rebar hassle is cut by 70%. Developer is happy because the construction schedule moves forward 6 days. The "expert on ICFWEB"....he still hasn't used the product because it is too expensive. |
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ShelterWorks
Registered Users
Posts:9
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| 11/10/2007 5:34 PM |
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I am a manufacuturer of a woodchip-cement ICF and would like to talk to someone very knowledgable about Novomesh. I would like to recommend it to our clientele of builders and architects and homeowners.
Do you have a contact person at Novomesh that has sufficient expertise to help lead me to a point where I can confidently recommend this approach? Thanks in advance.
Tom at ShelterWorks Ltd.
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greenbuilder
Registered Users
Posts:12
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| 11/22/2007 7:03 PM |
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| Hey guys simple solution, Helix steel fibers. I have been using steel fibers, initially Vertiforce and recently Helix for about 5 years and it is the only way to go unless you are constructing an ICF wall that will be classified as a retaining wall. |
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Quantum
Registered Users
Posts:262
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| 11/22/2007 9:06 PM |
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Yeah, it's easier. But it is simply not acceptable in Earthquake Country.
Further...
Quote:
GUIDELINES
Novomesh 700 fibers should not be used to replace structural, loadbearing reinforcement.
...
Novomesh 700 is acceptable to use assuming your wall is a simply supported wall, has a minimum wall thickness of 4 in and a
maximum height of 8 ft or has a minimum wall thickness of 6 in and maximum height of 10 ft, and a concrete compressive strength of no less than 3,000 psi.
We are building structural, loadbearing walls, peoples. And most of our walls are over 18'.
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Ian with ICF Builders
Posts:0
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| 11/22/2007 10:12 PM |
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This is true.....IF you are only following the basic minimum prescriptive allowances provided by the manufacturer in getting code approval. YOUR local engineer CAN use the data provided by the manufacturer (that was used to gain code approval) and DESIGN ACCORDINGLY. If you don't buy this, then all ICF structures built prior to the inclusion of ICF products in the newer codes were in violation of the LAW!!!
"If you are a follower, then you will always follow, if you would like to lead, then make a move and lead" |
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Quantum
Registered Users
Posts:262
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| 11/22/2007 10:32 PM |
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The LAW is one thing... reality is another.
Rebar is alot more work, hassle and expense, and I don't like that any more than anyone else, but fiber will never substitute. I suspect the next tremblor will tell the tale.
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Ian with ICF Builders
Posts:0
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| 11/23/2007 8:33 AM |
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The addition of fibers actually disperses stress on concrete more evenly.....making the "steel/concrete" mixture work more cohesively than that of a steel bar alone. As you may well know, steel is great in tension and flexural, concrete only adds one real major benefit and that is the compressive factor.....If the concrete wall or beam is subjected to movement with a steel bar in it, the first part of failure is the concrete losing the bond with the steel and failing on the tension side. With fibers (ie, Novocon 700 or similar), the entire beam has reinforcing dispersed in it, so you (may still have reinforcing steel members) now have a concrete beam that can absorb higher tension stresses before failure and additionally, with these fibers dispersed around any embedded bar, the failure of the bond will be at a higher stress level.....
I'm not sure if you are following my limited assessment here, but would submit that the addition of fibers, either to eliminate a percentage of conventional reinforcing steel or to augment reinforcing steel schedules is a good thing....and although it is not a "do all end all", it is a great advance in design technology especially when attempting to design structures to outlast seismic activity. I'm no Mark when it comes to holding alphabet soup, but have enough experience with these fibers that I use them on every project I own...many times in addition to a reinforcing steel schedule. My shop floor for instance has no reinforcing steel in it. 6" thick slab and it withstands 20k pound dozer loads, 16k forklift loads and has yet to show a crack. There are three mobile equipment lifts in this shop that move on areas that have no additional foundation elements under them and they have yet to cause any problems to this floor. I beg to differ the comment that fiber will never substitute for reinforcing....it already has and will perform without the problems that conventional steel reinforcing has...ie, corrosion etc. |
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Quantum
Registered Users
Posts:262
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| 11/23/2007 9:24 AM |
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Sure it will substitute in times of calm, to a very limited degree. I am suspicious of it though, particularly under tensional stress.
I have never seen Vertiforce, but I suspect it is iron, glass, or polyethylene fibers no longer than an inch, which have been extruded or drawn, and are less than a mm in diameter. They will be smooth, and there is no way concrete can substantively bond to them. OK, lots of them, but smooth means no bond, particularly for glass or poly.
To instead place tendons in a net configuration which grips the composite as a whole when stressed, just does it. My theories seem to be supported by the fact that there is essentially no limit to the height a rebar building can be built, but fiber buildings are limited to 10' tall! And I presume this is not in a seismic area.
Your shop floor's resiliance is I suspect due in large part to the good job of compacting substrata that you did. |
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walltech
Registered Users
Posts:467
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| 11/23/2007 7:12 PM |
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Quantum: Your posting above " 18' or taller" is not relevant to this site. Unless you have confused yourself this site is geared towards residential, and wall heights are floor to ceiling not footing to roof i.e. 18'. We have not used fiber but are hot on its tail right now, i.e. pigs tail, WWW.HELIXFIBER.COM
Randy, has posted his view above of Helix and it appears with good success and we are looking forward to using it soon on a comercial job in a few weeks.
Dave |
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Quantum
Registered Users
Posts:262
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| 11/23/2007 9:06 PM |
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I read the manufacturer's specs to mean total core height. Do you have substantive evidence that they mean 'before lateral support'?
Hm, just alot of rabid sales talk on the Helix website. The only technical confirmation I can find is on the Univ of Michgan website... the developer of Helix.
I remember a while back, seeing on the Discovery Channel a new type of concrete which radically bends, but this not only has fibers, it also is a special mix and has very low aggregates. No indication of whether Helix is in fact the fiber used. Comments here. Nothing in Wikipedia, which is disturbing.
It is a proven fact that non-ductile reinforced concrete is the building method most susceptible to seismic damage. (as opposed to steel and wood) So it would stand to reason that increasing ductility would increase seismic tolerance.
I may be wrong about this Fiber, at least Helix, but need actual studies and proof. I'll bet this stuff clogs boom pumps. And wouldn't the client think you're cheating him, with no rebar? |
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eric monkman
Registered Users
Posts:195
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| 11/24/2007 9:31 AM |
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Ian,dave, GB & Q : I fully admit to being a "DoubtingThomas" in the substitution of rebar with fiber.......
My past experiences have been with Polypro products mostly, once 20 yrs ago with steel fibre on an exposed slab. Rust city. LOL
But I have to say that the Helix product, if it has testing to satisfy my local P Engs...is making me salivate
Thanks guys.
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Quantum
Registered Users
Posts:262
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| 11/24/2007 1:14 PM |
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| Hm, I've done quite a bit of research on this subject yesterday and today and have come to some conclusions. But I am gradually realizing that certain key others in this forum do not give technical information out, whereas I've shared freely. I'd better not do this anymore. It is, what it is. |
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xexpat
Registered Users
Posts:18
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| 11/24/2007 4:47 PM |
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In commercial building and heavy construction, fibers of various types have sometimes been an ingredient in "high performance" (10,000psi and up) concrete mixtures. In addition to providing some compressive strength gain, it also (logically) improves flexural and tensile strength. I don't know the cost/benefit of fibers in more conventional concrete, but it seems that the technology is "trickling down" in conjunction with new fiber products.
Looking at the vendor's website, they say their slab product(s) are useful for eliminating temperature/shrinkage steel in slabs, but they tell you that it is not a substitute for structural reinforcing.
In other applications such as walls/columns/ICF it should allow some reinforcing steel reduction because of the increased flexural and tensile strength of the concrete, but it is necessary to have the physical properties (tests) of the specific mix in order to properly engineer the structure when you have lateral, wind and seismic loads to consider.
I don't think this is a 'magic bullet,' but I can see a potential benefit.
xexpat |
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icfblocks
Registered Users
Posts:265
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| 11/24/2007 5:48 PM |
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Still looks to me that everyone is looking for the "magic bullet" that will guarantee wall can be poured "without vibration" and with very little if any steel and still achieve the same end results. I would welcome the results if and when the bullet is found.
Lets not stop looking , it may be achievable. |
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Thanks,
Tom
www.advbuildingtech.com |
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dmaceld
Registered Users
Posts:469
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| 11/27/2007 6:43 PM |
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I just had a conversation with a Mr. Juarez at Polytorx, LLC this morning about Helix fibers. He argues that you can replace rebar in walls with Helix fibers, but there is an economic break point. Specifically, he argues that you can place enough fibers in the concrete to replace all the rebars, including lintel rebars, but it is not economical to do so. You can however, replace all, or most of, the usual vertical and horizontal rebars, keep the lintel rebars, and save money.
What he said to do is prepare the plans with rebar as normal and get the building officials' approvals. Then send the plans to Polytorx and they will determine what mix of fibers, from about 10 lbs/yd to 50 lbs/yd, is necessary to provide the equivalent strength. They will then provide an engineer's letter and calculations which you can take back to the building official and request a substitute of fibers for rebar. He claims they have never been refused permission to substitute. He would not, or could not, talk specific pricing with me because the fiber content for each job is variable, but it sounds like it will cost about $20/yd on up to use them.
He said they are currently in discussions with BuildBlock to supply the fibers through BuildBlock distributors.
Very interesting. How much one can actually take to the bank, or should I say building permit office, and how much is marketing B.S. I have no way of knowing at this point.
Just thought I'd share this for what it's worth.
My civil engineer cousin said there's a lot of snake oil out there, but he was not familiar with Helix. His opinion is fiber has it's place but replacing rebar is not one of them. Reducing rebar, maybe.
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Building house - what a way to spend retirement! |
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