Knee brace to timber pile connection
Knee brace to timber pile connection
(OP)
I have a steel platform with cantilever that I need to have a knee brace. It is supported by 14" dia timnber pile. what is the best connection (easiest in construction, cheaper) for the knee brace to timber pile?






RE: Knee brace to timber pile connection
RE: Knee brace to timber pile connection
RE: Knee brace to timber pile connection
RE: Knee brace to timber pile connection
RE: Knee brace to timber pile connection
it was the skin friction of soil that was critical which is not affected by the notch.
RE: Knee brace to timber pile connection
Mike McCann, PE, SE (WA)
RE: Knee brace to timber pile connection
RE: Knee brace to timber pile connection
Otherwise, a pile friction collar like Mike suggests is a common option (more expensive than some, but cheaper than an engineer getting clever).
RE: Knee brace to timber pile connection
RE: Knee brace to timber pile connection
BA
RE: Knee brace to timber pile connection
Dave
Thaidavid
RE: Knee brace to timber pile connection
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Knee brace to timber pile connection
The OP has provided no info on the loading this brace is intended to resist.
A W12x53 is a pretty capable pile cap compared to typical allowable bearing capacity of a 14" timber pile.
Since there is little info offered, I made assumptions just to see what kind of loading on a W12x53 would need a brace.
Say the W12 is a fixed cantilever beam, 60" long. Not true, but without information, I'll make that assumption.
What point loading at the tip of the beam is needed to produce an assumed modest bending stress of 18 KSI in the (unbraced) cantilevered beam? I get a point load of 21.2 kips. Deflection at the tip would be 0.37".
Ok, what does my little numbers game suggest? Quite a bit, actually.
1. A load of 21.2 kips (or whatever may be) is large enough to ask if the timber pile is capable of supporting this load (both structurally and geotechnically).
2. Any knee brace resisting a 21.2 kip force is going to put a significant bending moment into the timber pile. Again, is the pile capable of this loading? With a load of this magnitude even if it is, bending of the timber pile will probably make an brace essentially worthless (As the W12 deflects, the timber pile bends. Result - less than expected compression in the brace). Because of this horizontal load, I would be reluctant to notch the timber pile.
Maybe, if the OP provides the needed information, a realistic assessment can be made.
Note: My point in the above exercise is to try to demonstrate to the OP that "details" depend on the conditions. Don't just "pull out" some "detail" that may or may not be suitable.
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RE: Knee brace to timber pile connection
the load is less than that and yes, the cantilever would work.
i'm just used to using knee brace regardless of the load if the cantilever is more than 4'.
it's just a habit i got from my previous company, we usually design industrial structures not commercial.