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Re: Temporary housing going up on Coles
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Quite a regular
 
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2007/8/27 19:49 Last Login : 2009/6/10 14:44 From Under the Turnpike
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I'm sure the city is well aware of the construction happening at 6th and Coles - I lived right next door to the construction site (formerly a parking lot for 2 cars) for 2 years and for a about 6 months, maybe more, the construction came to a hault because of unsafe working conditions and permits...
Posted on: 2008/9/8 19:11
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Re: Temporary housing going up on Coles
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Home away from home
 
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Quote:
Is this a 4X12 joist in a series of joists and just this one sagged? I have a few theories. Most likely just natural warpage. It was straight but wet when installed. It has a huge hidden flaw ( like a big knot). Some plumber notched the hell out of it somewhere you cant see. Or my favorite - there was once a phenomenally obese person living in the house and their favorite chair was directly above this joist.
Posted on: 2008/9/6 23:14
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Re: Temporary housing going up on Coles
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Home away from home
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Had a peek at the ends... looks ok to me.
Looks just like what Trimjoist shows on their site. Also, click the link and look under "thick OSB ends" also check out their FAQ. Lots of good info. http://www.trimjoist.com/great.html
Posted on: 2008/9/6 21:39
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Re: Temporary housing going up on Coles
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Home away from home
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The mechanics I got, where I lose the confidence is in the material. Wood is pretty amazing stuff, but does wood really NEVER stretch or compress? Then how did my massive joist settle? How many years of high humidity does it take for the wood to give a little in summer, then not get it back in winter? If wood and glue are so stable why is every piece of plywood, MDF or chipboard I've ever bought warped, or warp soon after purchase? Yeah, clearly I love to argue construction and engineering with someone who knows what he's talking about. Neither of my 2 architect friends are real hands on structural types. One built a loft bed with 6x6 legs because he wanted to play it safe! I knew engineers at school who built lofted waterbeds in their frat rooms with 4x4's. One of my other favorite sites is bbs.homeshopmachinist.net/. Lots of experienced and incredibly knowledgeable folks there, but they also sometimes digress into the OT equivalent of the "Ho-foods" discussion. When they touch on politics and especially climate and energy it's a real eye opener to the way the rest of the country and world thinks.
Posted on: 2008/9/6 17:51
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Re: Temporary housing going up on Coles
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Home away from home
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I'm a licenced architect and if anything, tend to 'overstructure'. Working with good structural engineers keeps me on track in that regard.
If those trusses have the end material you talk about, they are fine. The end material is working to transfer that immediate bearing load on the end of the lower chord to the top chord and thereby transferring the load into the entire truss assembly; top chord, lower chord and intermediate diagonals. Another point sometimes lost is that while the bottom chord is in tension and the top chord is in compression, the load in the middle of the truss is zero, and that's why very little material is needed in that region. On another note, isn't this a better conversation than whether 'Ho-foods is coming here?
Posted on: 2008/9/6 17:00
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Re: Temporary housing going up on Coles
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Home away from home
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Quote:
There is a sheet material section at each end, perhaps as wide as the whole joist is high, fingerjointed in as well. Maybe if I step out of for lunch I'll pop a couple of shots of the joists on the ground if they're still there. I guess the whole issue revolves around how closely to calculate just how strong is "strong enough". I once read a book called "Structures: or why things don't fall down", in which they talked about the early European rail bridges. The Scottish engineers went by the seat of their pants, and many of their bridges are still standing. The French were more scientific and depended on math to try and optimize construction at a time when material science was in it's infancy, with far poorer results. I guess I professionally err on the side of caution, and as a 4th generation (at least) metalworker, don't trust wood much. It frightens me to see such light structure in a building that should last generations, all to save a tiny portion of the selling price.
Posted on: 2008/9/6 16:39
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Re: Temporary housing going up on Coles
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brewster wrote:
Quote: The strength, as I said, depends on the extension resistance of the lower bar, the trusses simply transfer the load from a directly downward one to a horizontal one, trying to pull the 2x4 apart. Deeper= stronger because the ratio of vertical displacement to horizontal is greater, thus to sag 1 inch, the lower 2x4 would have to stretch twice as far in a 12" deep joist as a 6" one. So while the bottom section of the solid 4x12 is doing the most, the next 2" above is still doing quite a lot, and so on, and the whole cross section of the timber is doing quite easily what the diagonal braces do. +1. I really didn't get a look at what the end condition of the trusses is, but if it is what you seem to be saying (that the bottom chord of the truss is taking all the load) then yes, they have a problem. But to be fair, the problem is not with the truss itself as a structural, load carrying assembly, but with the end connection detail of the truss to the top plate of the bearing wall. If the trusses have a vertical end member connecting the top and bottom chords, then they are ok, but as I said, I didn't get a close enough look...
Posted on: 2008/9/6 16:11
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Re: Temporary housing going up on Coles
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I was discussing with my neighbors the quickie construction going on and there were a few folk in the profession who agree with you. That is why I appreciate living in The Beacon and other construction that involves saving some of the wonderful architecture of the past. They really just don't build 'em like that anymore.
Posted on: 2008/9/6 14:50
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Re: Temporary housing going up on Coles
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Yup, while I'm not a pro carpenter, I happen to have built a few things in my life (like for my living) and know the difference between dimensional lumber and common lumber. If I had described the lumber as 3-1/2 wide I've have sounded like a geek. No, the trusses were "2" wide, that is 1-1/2 wide, significantly narrower than the 2x4 component. As for your saying a truss of this description is stronger than a piece of lumber of similar dimensions, I don't buy it. Cheaper, lighter, possibly safe? Sure. The strength, as I said, depends on the extension resistance of the lower bar, the trusses simply transfer the load from a directly downward one to a horizontal one, trying to pull the 2x4 apart. Deeper= stronger because the ratio of vertical displacement to horizontal is greater, thus to sag 1 inch, the lower 2x4 would have to stretch twice as far in a 12" deep joist as a 6" one. So while the bottom section of the solid 4x12 is doing the most, the next 2" above is still doing quite a lot, and so on, and the whole cross section of the timber is doing quite easily what the diagonal braces do. Could it be wasteful to use big hunks of lumber? possibly, but I don't believe it was weaker. OSB engineered joists don't alarm me the way these do. My whole POV is that lots of today's construction is meant to last only till closing, the whole thing is horrifying, the fact that is passes code does little to reassure me. I've seen some places around here go up impressively on piles with masonry walls, (like the place around the corner on 7th) and I've seen concrete poured in ditches and 4" cinderblocks topped with sticks slammed on top. I'd never buy the latter. My parent's live in a 8 year old condo on LI that has sheetrock cracks and separations, and nothing is square. So it goes...
Posted on: 2008/9/6 5:03
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Re: Temporary housing going up on Coles
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brewster wrote:
The supports are fingerjointed in, but they aren't 4" wide nor have sideplates holding them as in the website linked. I bet they were 3-1/2" wide? A "2x4" is only 1-1/2" x 3-1/2".
Posted on: 2008/9/5 22:58
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Re: Temporary housing going up on Coles
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I had a look. They are indeed engineered joists and are just fine. Your 4x12 sagged because of it's length and that it is conventional lumber. Engineered lumber, glu-lams and trusses are not only are stronger, but use less material and are able to be fabricated from smaller/waste lumber from other manufacturing processes, so there is a 'green' factor in there as well.
An engineered truss 25' long in place of your 4x12 would not sag. However, if your condition is a carrying beam, you would probably use a glu-lam beam. Think of what geometric form those little trusses are made of: Triangles. The only simple geometric form that is inherently rigid. Think Buck. Fuller, geodesic domes and space frames. Also, among the most important factors determining the strength of a truss assembly is it's depth. Deeper = stronger. The house at 6th/Coles is only about 12' wide (a guess). Not a huge span by any stretch. An old rule of thumb for sizing conventional joists is to take the span, divide by 2 and add 2 which is the depth in inches that a floor joist can be. So a 12' span divided by 2 =6. 6+2=8. So a 2x8 conventional joist would work fine for that house. With an engineered truss being stronger, there is no obvious problem with the type or size they are using. I did not get a good enough look driving by to see what the end connection conditions are.
Posted on: 2008/9/5 22:56
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Re: Temporary housing going up on Coles
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Home away from home
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yeah, 220....221, whatever it takes....
Posted on: 2008/9/5 20:02
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Re: Temporary housing going up on Coles
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On another walk by I saw a piece of joist lying on the ground for a closer examination. It's a little better than I described. The supports are fingerjointed in, but they aren't 4" wide nor have sideplates holding them as in the website linked.
But still, to get engineer wonkish, the entire floor's support is dependent on the extension strength of a 2x4. I have a 4x12 in my ceiling that is settled over 2.5" in it's 25' length, and you can bet that piece of timber was older slower growing denser wood than today's.
Posted on: 2008/9/5 19:53
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Re: Temporary housing going up on Coles
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Home away from home
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Quote:
Never.
Posted on: 2008/9/5 13:45
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Well, at least they stepped in when something was going wrong with the building at Jersey and First. Maybe they'll take a look at this project now that we're discussing it here.
Posted on: 2008/9/5 13:38
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Re: Temporary housing going up on Coles
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Brewster, is this the small house goingup right on the corner of 6th and Coles? I'll have a look....
As for the city inspectors, don't get me started....
Posted on: 2008/9/5 13:15
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Re: Temporary housing going up on Coles
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Home away from home
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Your link shows something FAR more substantial than what's in there. What I saw looks like they could have made it on site with a box of nails and some Elmers! Take a drive by and tell us what you think.
Posted on: 2008/9/5 4:04
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Re: Temporary housing going up on Coles
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Home away from home
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Quote:
Those are engineered wood trusses and are stronger than conventional lumber. Similar to the TGI wood "I-beams" you now see but with the advantage of being able to run ductwork, piping, etc. clear through. Thanks Icechute... cool.
Posted on: 2008/9/5 2:13
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Re: Temporary housing going up on Coles
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brewster said:
Quote: The floor joists in that place are 2 x 4's separated by intermittent vertical and angled 2x2's the way steel bridge trusses are done. I'm astonished. I saw that the other day and was surprised that city inspectors allow scissor trusses as support beams. I am not totally sure of the long term durability of this type of support as it is being utilized in this structure and have only seen them in wood frame homes from the Civil War era. The old beams in the homes in which I did see them were in good shape, but the beams were hewed by hand and were quite thick. Hmm... 2 x 4's separated and supported by 2 x 2's... maybe the architectural firm of Moe, Larry, Curly and Associates designed it.
Posted on: 2008/9/5 2:12
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Re: Temporary housing going up on Coles
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Home away from home
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Nothing 'temporary' about it....
Those are engineered wood trusses and are stronger than conventional lumber. Similar to the TGI wood "I-beams" you now see but with the advantage of being able to run ductwork, piping, etc. clear through. www.trimjoist.com
Posted on: 2008/9/5 1:50
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Re: Temporary housing going up on Coles
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Home away from home
Joined:
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suburb......... Oh my, what a scarey thought...
Posted on: 2008/9/5 1:50
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Home away from home
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Speak for yourself, we just hit 11 years, with no intention of moving.
Posted on: 2008/9/5 1:28
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Re: Temporary housing going up on Coles
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Home away from home
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Oh well, we all move back to the suburbs within 10 years of living here anyway.
Posted on: 2008/9/4 21:44
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Temporary housing going up on Coles
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Home away from home
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At least that's the way I see it, in the place going up at 6th & Coles. I know timber joists have long gone the way of the dodo, and now apparently so have the OSB engineered joist beams. The floor joists in that place are 2 x 4's separated by intermittent vertical and angled 2x2's the way steel bridge trusses are done. I'm astonished.
Knowing how the massive timbers in my home have settled over a century, I simply can't see that place standing 30 years from now, never mind 100 like many of our homes. On the other hand, I bet the plumbers and electricians love it, no joist holes to drill!
Posted on: 2008/9/4 19:41
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