For a straw bale infill wall, is a box beam required if the wall extends more than 12 ft. in hight.
We are planning a post and beam straw bale home with a shed style roof. the length of the house is 53 ft. and the width is 33 ft. The roof will rise along the length of the building, starting at 13 ft. from grade and rising to 21 ft. from grade. So, The wall infill will be approx. 20 feet high at its max. height and we are planning to put a box beam at the 10 ft. height. This seems like a sound decision, yet if it is not necessary, then we may eliminate the box beam. The structural component of the building is to be reinforced concrete, so we may create the box beam from concrete and connect to the concrete posts. Also, we are planning to use wood lath to tie the bales to the structure..(eliminating the need for a box beam?).
Thanks and look forward to your advice.
Gerardo
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Replies
I think you need an engineer to help you figure this out. If I understand you correctly, the posts and beams will be concrete. Forming and placing the concrete for 21' tall posts is not for the timid.
You need to make sure the foundation and footings can support the point loads under the posts, which presumably are carrying the roof load. I can see a lot of other potential issues that need considerable expertise to analyze.
Red flags are flying! As an engineer, i heartily agree with the previous poster that you need to have your design developed and approved by an engineer versed in reinforced concrete design. Standard practices for conventional wood framing won't transfer to the RC columns and beams you describe. An engineer will also be able to analyze the design loads for your structure which will almost certainly include consideration for wind loads on the 20' high walls. Unlike stick built structures, there is little redundancy and load-sharing in RC column and beam systems so you have to get it right. Be cautious and good luck.