Corner reinforcement at junction of concrete column and w ibeam
I would like to build a two story workshop using 8 inch wide cement block with concrete columns. The garage doors on the first floor are 10 feet wide. I plan on using a W8-31 I-beam to act as a lintel and support the 8 feet of block above it (the second floor of the workshop).
The I-beam is supported by concrete columns at each end and two of these columns are corner columns.
So, the question is, “How do I bond/attach the vertical rebar in the corner columns to the I-beam?”
A bit of explanation. This is for a building that in out in the sticks of Starr County, Texas. Mexican Style Concrete Frame with Cement Block Wall construction is the norm. For the above beam, one would use a 16 to 24 inch thick beam with a 6 strand rebar cage to span the opening. Then, one uses corner rebar at the intersection of the beams with the outside corner columns (the columns have an 8 inch square cross section with 4 strands of rebar). There would be corner rebar in the three planes.
I wanted to use a W8-31 beam to give me a taller door.
Replies
Why not just make your corner columns taller, and place the steel/concrete beam over the door opening higher (and raise the start of that end of the second story block wall)
That is a different design. What I'm looking for the the answer to the more general question is "How to attach vertical concrete columns to horizontal I-beams such that they can handle horizontal wind loads - think hurricanes." I'm trying to minimize the amount of time I spend with the structural engineer. I want to show him the design and have him do the final engineering calculations instead of having the engineer take time to lay out the design and do the calculations. Since I'm doing the drawing, it might take multiple iterations with the engineer and each visit costs money.
I have done some investigating and found that rebar hardware vendors advocate welding rebar couplers to the I-beam. I was wondering if there are other ways to accomplish the attachment.
https://www.youtube.com/watch?v=E4dCm9B4kW4
Above mason uses anchor bolts inserted in a filled CMU cavity through a hole in the I beam bottom web (fit while grout in the CMU cavity is flexible). In this case, there are also rebar and C section vertical elements welded to the I beam for connections above.
Your engineer will need to assess the contribution of the steel lintel to handle vertical or horizontal wind loads, combined with the other structural elements. (in addition to non-wind loads)
Attachment options will depend on the needs for horizontal or vertical bonding to the wall structures. If there is enough horizontal structure in your columns and walls, the I beam will only need to attach to resist forces up or down.
There is an interplay between engineering calculations and design.
In order to achieve calculations that indicate approval without this interplay is to over-design. This will come with increased labor and material efforts that could be avoided by concurrent efforts.
Thanks for the info. The comment on over-design is right on. Thanks!