flitch beams - bolts at support 1

[n3jc]

Hi, I got another question. I studied some articles you guys posted here before about flitch beams.

Lets say we have reinforced wood beam (flitch beam): steel plate + wood beam + steel plate
Im wondering if it is mandatory, to place bolts above supports - staggered them as many as required so the sum of their shear capacity is bigger than shear force at support.

In articles i found out its mandatory to do that when steel plate is not ending above supports but sooner. I can understand that because bolts need to transfer concentrated load from steel plate back to wood beam (at supports beam wood is the only element that has to withstand shear force).

but what about when steel plates are also lead all the way to the supports. I think its the same thing but im not sure. Any insight?

In calculation i assumed that whole load is transfered to steel plates. I think thats conservative but OK.

At the beam end bearing supports, only the wood side piece rest on the supports. Consequently, bolts at the ends of the beam must transfer the end reaction from the steel to the wood. So above calculation is OK? Right?


Sorry for another similar topic but i really want to study and master this topic.

 

[KootK]

I agree. Unless the steel delivers it's end shear as bearing to the supporting structure, you need the concentrated bolts to transfer that force back to the plies that do.

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.

 

[XR250]

I have gotten into the habit now of calling out 1/4" steel bearing plates at the ends of these things (at least on the heavier loaded ones). For a 2x10, they cut it back 1/4" to match the 9" steel depth and let the steel bear directly on the plate. It takes the whole "end bolts" thing out of the equation.