Double Angle bolted connection to existing concrete column

[sadienerd]

I am wanting to design a double Angle connection to carry a new W12x26 that is bolted to the new steel beam and bolted to an existing 16"x16" concrete column (expansion or epoxied anchors). My question is on the design of the anchorage to concrete. Can a double Angle all bolted connection be treated as a simple connection in this instance, ignoring any moment at the connection similar to the simple shear connections in AISC? If not are there some examples on how to determine the tensile load on the concrete anchored bolts. How do I determine the stress distribution to the bolts and angles. The plan is to use a double Angle connection with n=3. The beam is lightly loaded with max reaction of 4 kips. Is this type of connection typical or is there another connection type like a shelve Angle that is preferred in this kind of a scenario. Thanks

 

[Guastavino]

It's my understanding that the "pin" is in the angle flex and this application still has it in my opinion. I would treat it as a pin.

And I'm guessing you have a slab on top which will act to restrain the beam from rotating away from the face of the column, pure shear seems safe to me.

 

[thaidavid40]

For attaching to existing concrete walls and columns we often use a WT section, with an adequately wide flange width, and bolt the beam web to the WT's outstanding web. A WT with a wide flange accommodates the anchor bolts quite nicely. And it's easier to fit up than the double angles.

Thaidavid

 

[KootK]

I'll bolt a thin plate with horizontally slotted holes to the column and then two side weld a single angle to that. Easy fit up, lots of connection flexibility, and the ability to shift the plate around a bit to miss column rebar. If field welding is a deal breaker you can shop weld the angle and plate together at the expense of some tolerance adjustment ability.

For relatively light loads, you might get some rotational slip out of your horizontally slotted holes too. With heavy reactions, they'll bind up.

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.

 

[RPMG]

It is pinned, double angles are good, and cope the W12 to knife it in place (shim as req'd). Design for shear only. There will naturally be allowance for small tensile forces. Specify the exact anchor such as the epoxy adhesive or torque-controlled (expansion) anchor, material, and embedment. Hilti, Simpson Strong-Tie, and Powers provide free catalogs and free software. Spacing requirements for PI-anchors are generally greater than 3" OC.

I haven't run numbers or looked at the catalogs/software, but an example would be: Use 2 rows 5/8" has rod Hilti Hit-HY 200 epoxy adhesive @ 6"oc. Embed 6" into concrete. Total 4 anchors per connection.