Composite Steel and Concrete
Composite Steel and Concrete
(OP)
There are precast panels being supported by columns and we're doing a renovation where we need to open it up as much as possible. I'm going to bolt MC channels to both sides to provide 3 spans 30', 31'-6" and 36'. The panels have joints at each of the existing columns so I'm not sure if I can use them to provide a composite member to span the new supports. Also if I were to try to engage the panels for support would I have to epoxy the channels to the panels along with the through bolts?






RE: Composite Steel and Concrete
1) gives some serious consideration to the impact that channel bolt slip and compression zone gap closing may have on the panels. If ultimate strength works but you have to open up fist sized cracks in the precast to mobilize it, there could be trouble.
2) Depending on the panel to panel connections, all of your vertical shear may need to be carried locally be the channels at the joints.
3) where joints occur in the panel compression zones, there will be potential for lateral instability. Make sure those locations are braced laterally.
4) I don't like through bolting for this. You should be able to get more capacity from adhesive or expansion anchors and those will give you less slip and be more field friendly.
5) One hopes that bolt tension will provide some composite action at service loads via shear friction. That's tough to count on though as it's difficult to reliably pretension bolts in situations like these.
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.
RE: Composite Steel and Concrete
RE: Composite Steel and Concrete
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.
RE: Composite Steel and Concrete
RE: Composite Steel and Concrete
jiang46602 - We will bolt the channels on and put in our new columns, then remove the ones in the photo. There will be a few panels between spans more than likely so do you think it will be an issue if at the column location and at panel joints we put extra bolting to ensure the vertical loads are giving extra attention? I think there will be approximately two panels per span for each of my beams, two panels will be attached to one span of bolted/epoxied channels.