Base balustrade moment connection

[Redtelis]

Hi,

I am looking to check the shear and bending capacity of the attached connection. The post is a balustrade fixed at the bottom free at the top. Therefore, it transfers shear and moment to the base through the proposed fin plate. The shear and moment is 5kN and 7.5kNm. The fin plate is bolted to the balustrade I-section (web) and is cast in the concrete below. I know that it looks a bit odd as a connection but this is what is proposed by the architect.
The fin plate is 325 deep x45 wide x15mm thk and 150mm of it is cast in the concrete below. There is one row of 3No Bolts (maybe M16 GR8.8). The balustrade post is a fabricated i-section 90x90x15mm.

Could you please assist with a basic shear and bending check of this connection? I only need a high level check really, not going into much detail as I know moment connections can be very time-consuming.

 

[Redtelis]

Do you think that a P/A + M/Z check will be adequate for a high level check? I just feel that it's a very odd and weak connection especially resisting moments even if these moments are low.

 

[r13]

I'll do a quick low level check on 1) weak axis bending on the fin plate, and plate defection, and 2) twist on the bolts, and capacity of fin plate to resist bolt tear out. I don't have good sense on metric units, but I think this post won't hold much force.

 

[Deener]

I would consider this more of a pinned connection if only the web of the beam is connected to the fin plate. If you want to transfer the moment from the beam and into the fin plate, I would think that the flanges should be connected to the fin plate. Assuming you can transfer the moment into that fin plate, I would agree with r13's recommendation for checking weak axis bending on the net section (accounting for bolt holes).

 

[hokie66]

Forget the weak axis bending on the fin plate, it won't work in strong axis bending. You are trying to connect a fairly chunky H section only with a fin plate which is the weak link by far. The architect is way off base.

As a structural engineer, you should be able to do a simple(moment/section) modulus check, which will inform you that the steel bending stress is much too high.

In addition, you have the problem of connecting to the concrete kerb, where breakout would be the concern.

 

[HTURKAK]

The fabricated balustrade H section 90X90X15 mm is too odd. You could prefer RHS or pipe which will be more neat...

The resisting moment and shear are 5kN and 7.5 Kn-m are too high for fin plate with dimensions 45 wide x 15 mm thk.

P/A + M/Z check for strong axis f= 5000/(45*15) + 6*7.5*E6/(15*45**2) =1490 MPa. ??? No need to further check for weak axis..

 

[Redtelis]

Thanks for all your help and advice guys. It will not work under this moment. I just suggested to go for a standard moment base plate solution.