Has anyone come across anything like the acrow prop/ strong boy needling systems commonly used in europe and south america here in the US?
I will be working on a project this winter that will require a large opening on the side of a house. This house was build in 1917, double wythe brick exterior walls all the way around. One side of the house has about an 18′ L x 8′ H section where the outer wythe of brick has buldged out. the interior wythe has some buldge but not nearly as dramatic as the exterior wythe. Because part of the project consist of adding square footage to to house, we have opted to add a “sunroom” if you will, to the side of the house where this issue has developed. The thought is to take the buldged section down, replace it with a framed exterior wall (2×8 wall to best match the width of the current exterior walls)
Mainly wondering if anyone has seen the system mentioned above here in the States.
Replies
DanH
Wow Dan, guess its your time of the month... Why would you even chime in on (a basic subject) that you are obviously ingnorant about?
If you have never heard of this incredibly rudimentary process in masonry construction and repair, you should keep your comments to yourself.
If for those a little more familiar with a line of work called "construction" my question is unclear, I am wondering if anyone here in the US has seen, or knows where to purchase acrow props and strong boys. Have had not luck searching my local/surrounding markets.
needling
DanH. You should be ashamed of yourself. Now say you are sorry.
Mark,
I feel your pain with Dan. Seems he has the need to post to any and all subjects posted no matter his ignorance of the topic. Any attempts at humor are (IMO) fine and can actually be pretty funny. But when he has to add additional comments that make it seem as if the original post/question doesn't make sense (through no fault of his own limited capacity mind you)--that's where he needs to learn to draw the line. It doesn't help anyone; including himself.
To the point of your OP:
I was not familar with needling either. That is one of the great things about breaktime; you have an opportunity to learn before throwing your two cents in willy nilly. Anyhow, I looked it up. Seems like a good way to go for the job you have coming up. The way I see it, the strongboys are the same concept as adjustable jack posts, but allow for a capacity to handle the load eccentricly. Like you, I couldn't easily find a supplier. I have a theory as to why which may help.
IMO bracing for eccentric loads (particulary masonry units that lack tensile capacity) are complex and way more dangerous to handle than clear axial loads. I would think that an engineer would have to be involved from the get go. In fact, the manufacterer of these type of braces may only deal with engineers due to liability issues; particualary in the U.S. where folks are prone to be far more litigous. My guess is that these type of braces are going to quite expensive to buy outright. Perhaps to the point where it only makes sense to buy them if you are using them regularly. Come to think of it, it may be a part of your job you might want have (or have to have) subed out to a specialty supplier who has engineers on staff--muck like a scaffolding company handles large commercial projects. My guess is that you may also have to "needle" around with a specialty suppliers/rental company in order to make some headway in getting hold of these puppies.
The other option would be to partially take the concept and make your own bracing system. It might be that you are able to "needle" in short sections of 3/8" or 1/2" flat steel at mortar joints and use regular jack post from both sides (if you have access). You may have to use quite a few to get the job secure. In fact, consulting with an engineer might be warranted as well if you go this route. I would also think that you may want to independently brace any and all floor& roof loads that flow into brick bearing wall in order to minimize the risk.
pricy!
You are right that because the US is so prone to litigation this system has yet to be know here. I have contacted a company in Australia and after they went back and forth between the lawyer they use their design team they came up with a quote to ship me 15 sets, acrow props (a much more versatile version of a jack post) and strong boys. the price tag was more than i am willing to spend on it right now. at 4k i dont see the pay off time justifing the expense.
Although they were made by masons for masons, i see a lot of uses for this system and had not even considered contacting someone to manufacture them myself...an enticing thought.
I've several times seen props matching the pictures of "acrow props" being used to support forms while pouring concrete floors in multi-floor steel/concrete construction.