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     Ratbuell |
Just curious about a safe working load for my garage... Bank-barn construction, circa 1987. Main level is cinderblock walls faced with stone. 32x64. One 3" post every 16' along the centerline, rated for 13,100#. Centerline (long axis) is four "Microllam" 16"x1-3/4" laminate beams, mated together to form a single 7x16"beam, supported by the posts. Second story floor joists are 2x12", 16" O.C., X-braced with metal every few feet. Floor joist span is 16' (exterior wall to spine; spine to exterior wall). Floor surface is 3/4" OSB (actual thickness). Now...I've got the second story filled with spare parts - bikes, and cars: engines. Heads. Transmissions. Wheels. Small parts. This is also where I have my motorcycle "workshop", currently housing four Buells in for service (3 tubers and most of an XB), plus a Handy 1000 lb bike lift table (ship weight on that was right around 400#). Any guesses what a safe working load is in this place? I know it's overbuilt - the doorway headers are freakin' 2x12's - but I don't want to come out one day and all my upstairs-stuff is now downstairs. Upper roof truss is full-span, hip-roof, no structural walls in the second story interior - perimeter only. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Blake |
Take a photo and post. I'm guessing, but it sounds like you have a span of 16' for your 2x12 floor joists, which are supported on one end by the masonry wall and the other by the conjoined beams. Thing is that details can be the weak link. Are your three inch posts schedule 40 steel pipe? How are they supported, fully reinforced concrete footer? What is soil bearing capacity there? The thing with wood is that it will take an amazing amount of load for a short time, but over the long haul it will sag, especially if exposed to high humidity or fluctuations in humidity. Without knowing the grade of the 2x12 joists, it is tough to give you a definite answer. If you can find a legible grade stamp and take a photo of it, that would be helpful. If your locale is governed by a building code, and the building meets code, then it ought to be good for whatever load capacity is prescribed for that type of structure. It could be as high as 200 PSF floor dead load (200 LB per square foot). I'll dig out my Wood Structures book next time I get a chance, but it's out berried in storage, so it might be a while. Do the floor joists have lateral bracing (intermittent diagonal bracing nailed between at least every other pair)? | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Blake |
Oh, I almost forgot. You and your mongo two story man castle suck! | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ratbuell |
Yes, the joists have a 16' span from masonry to center beam. Yes, the posts are set in concrete and the sticker on them has the 10,300 rating. Also says 11 gauge walls. yes, the joists have X bracing - metal, not wood. X braces are at 8'; joists are boxed about 2' from the end. Here is one of - literally - two grade stamps I found in the whole garage:  A shot of the joists:  And a shot of the workshop space. The bike lift is directly above the white car in the garage; I am standing over the car behind it (under the cover), to take the photo.  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ratbuell |
And remember - I had to die, put two shattered legs back together and learn to walk again, cope with two head injuries, and watch my marriage fall apart before I could get here. I've earned it. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Griffmeister |
Yep, that's headed for ground level status any day now. Seriously, if you were worried or wanted to really boost your capacity, you could add supplemental support at mid-span. Wouldn't have to be as large of a beam as the main one. Worst part of that scenario would be the extra support columns and digging more footings for same.  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Toona |
I'll bite... What kind of car is the "longroof"? | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ratbuell |
That's my 72 Plymouth Satellite station wagon. Currently a high-13 second smallblock street car, plan is to install the '05 5.7 EFI Hemi and autostick out of my totalled Magnum R/T. Since I have the whole Magnum, I have the harnesses, computers, everything I should need. I don't think I'm anywhere near "tumble-time" yet...no creaking or popping up there...but I'm trying to avoid getting there if I can help it. Keeping a number in the back of my head will help curtail my "hoarding" of engines. And wheels. And more motorcycles. I'm trying to stay in the mindset that I may have the square footage...but that doesn't mean I have the weight capacity. Reality is, I probably don't have any more in there than a normal furniture/appliance load, which is what the place was designed to be (looks by the bare studs to be a 2 BR apartment with kitchen and bath, and my workshop is in what should have been the living room. But I'd rather find out *before* the crash, that I'm getting close to the SWL...  I've just never parked motorcycles..."upstairs" before. Its weird. (Message edited by ratbuell on June 24, 2012) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Kenm123t |
Invite Blake to visit get FREE engineering done. Make Blakemail pics of his man cave droolings If you let him hang around he may just do all the upgrades for you. We just need to find folks to tell him he can't do it and post it on Badweb. When he gets done you can have 5-6 layers of hemis stacked by forklift on the second floor  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Oldog |
Rat: s-dry is air dried pine lumber #2 grade most laminated items are made of #2 or faced with it, depending on manufacturer. about average.... As I am not a structural engineer those little metal braces probably don't add much to over all stiffness. IMO they are there to hold the framing in place for the subfloor install // insulation, They may enhance it if they prevent the joists from twisting | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Blake |
COFI = Council of Forest Industries (A Canadian Lumber Grading Agency) 110 = Lumber Mill Identification # S-P-F = Spruce Pine Fir (type of wood) S-DR = Surface Dried No 2 = Structural Grade #2 Length = 16' Laterally braced and decked dry duty long term loading (10yrs or more) Allowable bending stress (Fb) = 775 PSI Based on some quick calcs everything points to 40 PSF live load (LL) plus 10 PSF dead load (DL). Dead load is just the weight of the supporting structure (joists and beam and decking) and any flooring (tile & grout, padding & carpet etc). Live load is stuff, pets, and people. Put the really heavy stuff near the outside wall. That Microlam looks to be oversized according to their current info, but their newer beams may be stronger than when your barn was built. See page 7 of... http://www.dickslumber.com/lumber_wood/documents/M icrollam.pdf You have 32' floor framing length and 16' column spacing. Table says you only need a 5-1/4" x 16" Microlam to be good for 40 PSF live load plus 30 PSF dead load. Those Microlam beams be stout! Your floor joists and colums are your limiting factors and they appear to be right on for 40 PSF live load, 10 PSF dead load. That girder beam is heck for stout. Here's the very crude (just total load capacity), unchecked calcs. I'm not a licensed structural engineer!
(Message edited by blake on June 24, 2012) (Message edited by blake on June 24, 2012) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Blake |
Being unbraced, the girder beam allowable may likely suffer some significant reduction, thus the apparent discrepancy. 40 PSF is a lot of load capacity. Think of a 10' x 10' area, that's 100 SF and so a load of 40x100=4,000LB on that area, even in the middle of the spam, is permissible. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Blake |
spam? I must be hungry. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Blake |
Olddog, That last thing you said is right on the money. >>> those little metal braces ... enhance (floor strength) if they prevent the joists from twisting. Exactly! At greater than a certain span, a lack of lateral bracing leaves floor joists unstable and tending to twist (lateral-torsional buckling) well below their elastic stress capacity. The same is true for steel beams too. So see, all you need is some additional lateral stability and you can increase your span.  (Message edited by blake on June 24, 2012) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Kenm123t |
insulate then screw and glue 1/2 inch ply wood to the the underside See what I mean about the engineering ! cant hold him back. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Rkc00 |
I think your deflection calc is wrong. Think d=.518" Looks to be designed to normal loads we use. What is the width and length of the plate on top of the column? Need to check the bearing pressure on the girder. The micro-lams are very strong in bearing. The reaction load on the center column might need to be increased by 25% due to the continuity of the girder. Are all the plys of micro lam spliced at the same location over the center column? If they are one piece (32' long) the reaction load will be more in line with 16000# at 50 PSF total load. If you have a 2'x2 concrete footing below the column you would have a bearing pressure below the footing of 2 tons/sf. You would need to know what type of bearing pressure you have in your area for your soil type. A 2x2 footing would be the smallest we would show on a job. If the 2x2 footing is at least 1' thick you would not need any steel reinforcement in the footing. Are the garage doors on the wall that the floor joists bear on? If so they might be the weak link. What size doors are they? 8'? 16'? Would need more info to check the rest. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Kenm123t |
OK Blake Mike lets meet at Joes Bring your favorite calculators and have a Design off. I have dibs on Film and TV rights ! Hmm Badweb TV we can hack what ever you have! M/Cs houses Stators Ecm's power plants Who needs Mythbusters!  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ratbuell |
I'll make sure there's beers n burgers for all Yes, the garage doors are in one wall, the one under the lift. 7x9' residential doors. Facade is arched but I don't think they're structural arches. I'll look at the headers in the morning (but considering even the entry doors have 2x12 headers...I'm willing to bet they're sturdy!). Oh, did I mention? The guy who built the place was a contractor. Built it for himself and his family. The home is double-walled, PLUS a stone exterior. Yeah. It's overbuilt. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ratbuell |
And thank you Blake - that's impressive, and all good news! As you can see, I've been keeping the "heavies" towards the edges anyway. But good to know I'm still pretty safe! | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hootowl |
Are the steel posts filled with concrete or are they hollow? | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Oldog |
So see, all you need is some additional lateral stability and you can increase your span. I need to decrease my span over all especially horizontal  } |
