Quote:
Originally Posted by Charlatan
FYI - JT Kirk is an engineer (structural I believe).
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Correct.
22 years designing bridges and infrastructure since finishing University in 1989. 11 Years working at UMA / AECOM in the bridge group. 9 years prior to that at Planmac. 2 years currently designing and building railway bridges.
Always designing infrastructure - mainly bridges.
Worked in Construction prior to that as an Iron Worker. Fabricating and erecting structural steel.
I've got bridges all over Toronto and Southern Ontario that I was either part of the design team, or the Lead Engineer on.
---------- Post added at 04:07 PM ---------- Previous post was at 03:52 PM ----------
Quote:
Originally Posted by cj2112
I seriously doubt that railroad spikes were used. This is a railroad spike:
Is that really what they used?
A few things from the post above:
Just how do you know the columns were overloaded? Note that it wasn't the columns that failed.
What is the proper spacing of the columns? Again, note that it wasn't the columns that failed.
I have yet to see an elevated deck w/ cross bracing on the columns. Again, note that the columns did not fail and still appear to be in place. I've seen a lot of houses in earthquake territory built on stilts w/ no lateral cross bracing. Hell I've seen freeway overpasses and entire piers with no lateral cross bracing. If the columns are properly fixed to the ground (concrete, or pier blocks) the bracing is unnecessary.
The lack of railing did not cause the deck to fail.
A "proper joist hanger" is unnecessary. People used butt joints for a very long time before joist hangers were invented. |
Yeah, I'm familiar with bridge design.
The concrete columns do not require X bracing because they are considered fixed connections. Fixed at the footing and fixed at the cap beam because the rebar runds right from the bottom of the footings, through the columns and into the cap beams.
Bolted connections are not considered fixed connections, they are pinned connections and thus are laterally unstable unless they are braced, or fastended to a brace frame directly.
The stilts you see coming out of the ground are piles and they are considered fixed at the ground.
If the OP had 4 columns, correctly laterally braced, he would not have taken the express route down.
Here's a simple video:
Look around and you will see that buildings MUST have some sort of lateral bracing:
1. X frame
2. Moment Frame
3. Diaphragm
4. Concrete core
Just because you've seen decks without X bracing doesn't make it right.
Also, Pressure Treated Wood is the WORST shit wood out there.
Wood is either No. 1 Structural (usually used for bridges and formwork, etc.)
No. 2 - typically used for framing houses and the like.
Not Rated - shit wood so full of knots and imperfections that it cannot be rated and is sent to the Pressure Treating companies so they can do something with it.
In Canada, you will see SPF No. 2 stamped on most dimensional lumber you see in the stores, etc. SPF stands for Spruce, Pine, Fur (one or the other) and No. 2 is the grade. You will not see this stamped on PT wood.
I think you may be able to buy No. 2 Pressure Treated Wood, but I have not seen it.
And yes, a 15' long unbraced 4 x 4 is overloaded on what I can estimate from that photo, whether it failed or not. Though the design of the column is based on the intended floor loading. If this was Toronto, the minimum loading I would consider would be 1.8 Kilopascals, or about 40 pounds per square foot.
As to the lack of a railing not being responsible for the collapse - I agree, however, the very fact that it was not present is an indicator as to just how well the deck was constructed. A well constructed deck would have had a proper guard in place.