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KemoSabe
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Discussion Starter · #41 ·
Upon further review, I think this "test" is flawed. In the real application, the joist would be supported on both ends as well as being tied together. How about a side by side test. Build 2 mini floor systems out of 2x4's and install bridging in one system. Then add the weight and see how much differently they perform.
2x4s don't have enough depth to make a substantial difference. Maybe 2x8s would make a nice test model.:thumbsup:
 

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Super Moderator
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2x4s don't have enough depth to make a substantial difference. Maybe 2x8s would make a nice test model.:thumbsup:
Maybe rip them in half (or use 1x4's) and build it to scale. Just tryin to keep the cost down for ya. Or maybe we could take up an offering.
 

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solar guy
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Which is the point of the test, taken to an extreme. The bridging is the structure in this case. Centerloading the model and transfering the load to adjacent joists. It's really not about the science as much as it is the destruction.:laughing:
Remove the pieces you have on the ends of the joists
they are acting as a partial bottom chord in this case as the end joists are short and very stiff considering the spans.
2 dollah says the things collapses
 

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KemoSabe
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Discussion Starter · #45 ·
the 1x3s will eventually creep and pull the staples out
You almost got it right, the staples pulled through the firring strip bridging that has been out in the rain for 3 days.:laughing: I'm gonna do this again with 3/4 decking and 1x3 pine. 295lbs did it in. The OSB didn't fare well upon the staples pulling through either.:whistling
 

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Pro
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You almost got it right, the staples pulled through the firring strip bridging that has been out in the rain for 3 days.:laughing: I'm gonna do this again with 3/4 decking and 1x3 pine. 295lbs did it in. The OSB didn't fare well upon the staples pulling through either.:whistling
max out your credit card and buy a sheet of 3/4 cdx fir. try solid blocking. allegedly solid is the way to go. that's what i always do.
 

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KemoSabe
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Discussion Starter · #48 ·
Any close neighbors call the cops when it came crashing down? Dogs didnt go crazy, car alarms go off or anything? :laughing:
I set that last 25 on there very carefully, took 2 steps back to grab the camera and all hell broke loose.:w00t: A couple creaks and "KACHINGCLANGCLUNK". Nobody even came to their window to see if I was OK.:sad:
 

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Pro
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allegedly metal x-bridging is a better connection than wood x-bridging. get some tji scrap and gear it up with metal x's. i wonder if the flanges will pull apart.
 

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solar guy
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max out your credit card and buy a sheet of 3/4 cdx fir. try solid blocking. allegedly solid is the way to go. that's what i always do.
Again you're missing the point
Even if you use solid blocking if there is no chord on the bottom tensioning the structure the nails will start to pull. Tjhe only reason that experiment held together as long as it did was because of the blocks holding the very short end joists from spreading.
Don't believe me
repeat the experiment without the band blocking holding the two end joists together. I would be willing to bet that it fails much sooner.

Nail a 2x to the bottom of the joists at the bridging and I bet it holds 4 times as much.
 

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KemoSabe
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Discussion Starter · #53 ·
max out your credit card and buy a sheet of 3/4 cdx fir. try solid blocking. allegedly solid is the way to go. that's what i always do.
Those days are over for me, divorce lifted that burden from my shoulders.:thumbup: I like the fact that as the joists shrink over time, the X-bridging tightens up as a result. It's astonishing actually. You should try it on the next frame.:thumbsup:
 

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Pro
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Again you're missing the point
Even if you use solid blocking if there is no chord on the bottom tensioning the structure the nails will start to pull. Tjhe only reason that experiment held together as long as it did was because of the blocks holding the very short end joists from spreading.
Don't believe me
repeat the experiment without the band blocking holding the two end joists together. I would be willing to bet that it fails much sooner.

Nail a 2x to the bottom of the joists at the bridging and I bet it holds 4 times as much.

2x by itself is likely to hold a good amount of weight without any x's. the whole point of what my south jersey friend is doing is to show that bridging adds rigidity to a floor system. he may also be showing off his staging gear a little.:whistling
 

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Al Smith
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2,392 Posts
Again you're missing the point
Even if you use solid blocking if there is no chord on the bottom tensioning the structure the nails will start to pull. Tjhe only reason that experiment held together as long as it did was because of the blocks holding the very short end joists from spreading.
Don't believe me
repeat the experiment without the band blocking holding the two end joists together. I would be willing to bet that it fails much sooner.

Nail a 2x to the bottom of the joists at the bridging and I bet it holds 4 times as much.

I don't think the end joists were restrained by the lengths of 2 X 6 you see laying on the garage floor there.
 

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Pro
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Those days are over for me, divorce lifted that burden from my shoulders.:thumbup: I like the fact that as the joists shrink over time, the X-bridging tightens up as a result. It's astonishing actually. You should try it on the next frame.:thumbsup:
hope i don't like to get divorced and be reduced to watching joist shrink over time to be astonished :no:
hope you're using stainless steel staples on your ACQ boards
 

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Jeff
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allegedly metal x-bridging is a better connection than wood x-bridging. get some tji scrap and gear it up with metal x's. i wonder if the flanges will pull apart.
For the TJI experiment solid bridging screwed in would be stronger yet wouldnt it?
 

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KemoSabe
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14,233 Posts
Discussion Starter · #58 ·
Again you're missing the point
Even if you use solid blocking if there is no chord on the bottom tensioning the structure the nails will start to pull. Tjhe only reason that experiment held together as long as it did was because of the blocks holding the very short end joists from spreading.
Don't believe me
repeat the experiment without the band blocking holding the two end joists together. I would be willing to bet that it fails much sooner.

Nail a 2x to the bottom of the joists at the bridging and I bet it holds 4 times as much.
I agree on all counts. The point I was making is that the bridging will transfer load to the other joists. I think this model made that point well. :thumbsup:
 

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Pro
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For the TJI experiment solid bridging screwed in would be stronger yet wouldnt it?
i'd say. you won't see me doing that though. too labor intensive.

bridging definitely stiffens the floor. does it have load bearing properties? no. it's a good practice to take some bounce off the joist. the other advantage is that under heavy loads bottom of the joists tends to want to kick out. bridging prevents that from happening. so does rim board and intermediate blocking.
 
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