Larry Caldwell
Elite Member
It's hard to attach the TECO clips to a steel beam. All that welding would set the house on fire.
Glulam Beam - Checking Problem
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dstig1
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And that's why there is more than one option in this world. That works for you, but would not fit in this house style. It turned out perfect - for us and the house.
timbatrader
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As the ex owner of a gluelam factory I am pretty sure the timber used in that that beam was not at the correct moisture content for use in that application either a mistake at the factory or not correctly specified when ordered My guess the remedy is steel plates to reinforce and a large hollow dummy beam custom made to wrap around to restore the Timber gluelam "look"
I think you're doing the right thing, getting the manufacturer involved. Besides the bottom being in tension, there is shear in play with higher shear stress near the ends. Those cracks could impair the beams ability to withstand the shear.
rScotty
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I wouldn't worry about it. If you haven't coated the end grain of the gluelam best do so. In dry climates it is good building practice to coat exposed end grain with a penetrating wax like "Anchorseal". That will slow down the moisture loss enough to prevent most splitting. Do it now.
As for tension vs compression it's like Snobbs says, "... depends on the rest of the structure". The moment you attach anything that is not parallel to a beam the stress analysis becomes overconstrained and somewhere between difficult and impossible. Throw in unavoidable buildng settlement, natural materials, and low humidity and most engineers are going to vastly overdesign that beam. And gluelams are spec'd conservatively in the first place.
For the new engineers and self-taught desgners on the forum, it helps when doing analysis on an indeterminate beam to assume the original calculations were done correctly for a static structure and then take a look at the worst case:
So ask yourself, "Suppose that it is in fact a total delamination, and it takes place for the entire length of the beam. Now you have two beams aligned parallel and replacing the orignal beam. What does that change?
rScotty
As for tension vs compression it's like Snobbs says, "... depends on the rest of the structure". The moment you attach anything that is not parallel to a beam the stress analysis becomes overconstrained and somewhere between difficult and impossible. Throw in unavoidable buildng settlement, natural materials, and low humidity and most engineers are going to vastly overdesign that beam. And gluelams are spec'd conservatively in the first place.
For the new engineers and self-taught desgners on the forum, it helps when doing analysis on an indeterminate beam to assume the original calculations were done correctly for a static structure and then take a look at the worst case:
So ask yourself, "Suppose that it is in fact a total delamination, and it takes place for the entire length of the beam. Now you have two beams aligned parallel and replacing the orignal beam. What does that change?
rScotty
Larry Caldwell
Elite Member
I take it that it's been a while since you did any vector analysis?
rScotty
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It that your attempt at answering the beam question? If so, I don't understand it.
Can you elaborate?
rScotty
Larry Caldwell
Elite Member
Two smaller beams are weaker than one large beam. The bending strength of a beam depends on the depth of the beam, and slicing it lengthwise only weakens it. Look at an extreme case where you slice the beam into 3/8" lath thicknesses. It would hold up very little.
OP
Pettrix
Platinum Member
The design engineer said that the beams were "oversized" by about 70%. The glulams sit inside concrete beam pockets on the concrete wall.
The glulam engineer said the repair might include 10" + timber bolts run through the bottom of the beam, possibly an epoxy being injected. More info coming this week. They also said the checking typically is not a structural issue unless it goes ½ to full way through the width of the beam. The rest appears to be standard checking. Seasonal checking in the wood fiber is a release of internal stresses caused by the drying process.
Supposedly deeper beams check more than shallow beams due to the higher grade material which is more dense and could hold onto moisture longer than the less dense material at the center. As the higher grade dries, especially if it is rapid, the tighter wood grain will pull away from the cores wider wood grains. There is more wood and more prone for checking in deeper beams.
The glulam engineer said the repair might include 10" + timber bolts run through the bottom of the beam, possibly an epoxy being injected. More info coming this week. They also said the checking typically is not a structural issue unless it goes ½ to full way through the width of the beam. The rest appears to be standard checking. Seasonal checking in the wood fiber is a release of internal stresses caused by the drying process.
Supposedly deeper beams check more than shallow beams due to the higher grade material which is more dense and could hold onto moisture longer than the less dense material at the center. As the higher grade dries, especially if it is rapid, the tighter wood grain will pull away from the cores wider wood grains. There is more wood and more prone for checking in deeper beams.