Proposed steel beam to existing concrete wall connection advice

Question

Proposed steel beam to existing concrete wall connection advice

mrzift (Structural)

(OP)

22 Jun 20 04:11

Hi all,

I need some advice for a detail I am struggling with. I am designing a roof deck which will be fixed to existing concrete panels. I'm struggling with one detail which involves the fixing of a steel beam to the existin 180mm thick precast concrete walls on either end. (see attached sketch).

At the connection, there is approximately 160kN which I have utilised a spreader plate fully welded to the steel beam ends to transfer this load through 10 chemically set bolts (M20) embedded into the panel. This beam is supporting a primary cantilever beam which I believe will induce some rotation at the connection and consequently additional stress through each fastener.

The beam is ~4.9m long and is a 310UC section (due to height restrictions). I'm wondering if there is a better way to do this connection - i'm considering having a plate welded from the beam end to bear directly ontop of the concrete panel.

Retrograde (Structural) · Answer 1 · 2020-06-22 04:22:42

Do you need 10M20 chemsets for that load? I would have thought 4 should do the trick.

mrzift (Structural) · Answer 2 · 2020-06-22 06:11:51

@Retrograde, you are right, the number and size of bolts is well over what is required for shear. I'm mainly concerned with any rotation induced by the cantilever beam which may add additional stresses at the ends - not really sure how to work that out.

Lomarandil (Structural) · Answer 3 · 2020-06-22 07:20:08

Is something else driving the end plate connection?

Seems the simple way out would be to put a shear tab on your embedded plate, then bolt the 310UC to that. More constructable, accomodates rotation and all your chemsets see is the eccentricity of the tab.

----
just call me Lo.

r13 (Civil/Environmental) · Answer 4 · 2020-06-22 15:30:47

The bolted connection suggested by Lo is a good idea, it shall be used at least for one end to avoid problem in fitting the beam into place. You can check the bending due to the cantilever beam by placing reaction on the sitting triangle plate, then resolve the moment into the anchorage system.

mrzift (Structural) · Answer 5 · 2020-06-25 02:50:42

RE: Proposed steel beam to existing concrete wall connection advice

mrzift (Structural)

(OP)

25 Jun 20 02:50

Thanks for the help guys. Very much appreciated!

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Proposed steel beam to existing concrete wall connection advice