Cantilever Support

[LOKSTR]

I have a 10' long cantilever beam attached to a concrete slab by using 4 Hilti bolts. See the attached sketch.

Can I assume that my support for cantilever is completely fixed or not?

 

[DaveAtkins]

You have no choice BUT to design it as a fixed support.

Otherwise the beam is unstable.

DaveAtkins

 

[vandede427]

Atkins is right, the connection needs to be completely rigid. But I think what you're asking, correct me if I'm wrong, is referring to any torsional rotation that might occur in your concrete beam.

 

[rb1957]

you Could assume an elastic support, but it Has to react shear and moment, so you're going to have tension is one pair of bolts ...

 

[BAretired]

The answer to your question is that the support is not completely fixed. It will move vertically and it will rotate under load from the cantilever. A fixed support does not move or rotate.

BA

 

[connectegr]

"kinda" fixed

The endplate/anchor connection you show is technically a moment connection. But the moment capacity is probably small and the support may not be rigid enough.

http://www.FerrellEngineering.com

 

[DaveAtkins]

BAretired is correct--the SUPPORTING beam is not fixed. It will twist. But it must take the full moment from the SUPPORTED cantilever, as a concentrated torsional moment. And as I said above, the plate connection itself must be treated as a fixed connection.

DaveAtkins

 

[DHKpeWI]

Have you considred the capacity of the anchors? Are you aware of the changes in the methods to determine the capacity of expansion and epoxy anchors? In some states it is no longer acceptable to you the values printed in the producers catalog.

You will want to download the ICC reports that guide you in the design of these anchors.

Chesk out the following site:

http://www.icc-es.org/reports/index.cfm?search=search

 

[connectegr]

Hilti Profis, is a free download for the design of your anchors.

http://www.FerrellEngineering.com

 

[slickdeals]

I suggest using epoxy anchors whenever tension loads are involved. Expansion anchors are good in shear, but I am always scared using them for tension loads. The mechanical action is dependent on the proper drilling of the holes. The chances of an iron-worker using a bigger drill bit are too high. Epoxied anchors too have issues but maybe more forgiving than expansion anchors.

What do others think?