Integrated Buildings & Structures

I need to design 2 story reinforced concrete building on top of an existing  2 story building with masonry brick walls. The concrete walls are sitting on top of brick walls. The building is in low seismic area (horizontal load = 1% dead load). I have not seen and designed such a building.

1- Can you please let me know if this is possible? 

2- Any references for attachment of reinforced concrete to brick wall?

3- What are the special requirements should I consider in designing of this building?

thanks

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Amir Eghtesadi Aff.M.ASCE
Thornhill ON
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My concern would be getting the additional load transferred to a new foundation, not the one the old brick building is supported on. If I were doing something like this. I would design a frame of some configuration that would sit over the old brick walls and support it on an independent foundation if possible, and allow for movement between the old and new walls. Without more information, that is about the best I can offer.

Good luck!

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Stacey Morris P.E., M.ASCE
ETI Corporation
West Memphis AR
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Dear Amir Eghtesadi


You can use the FEMA 356 for seismic rehabilitation .
If you have access to Iran's bylaws, 376 regulations is very useful.
You can also use FEMA 695 to determine building's R parameter.
I've worked and researched a lot on this building model so I can provide more help if you need it.

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Reza Mokarramaydenlou, Ph.D., C.Eng, P.E., S.E., M.ASCE
Structural Engineering and Seismic rehabilitation Consultant
Mokarramandpartners LLC

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Hi Amir

I am not familiar with details of your project, but one thought that comes to mind is to actually construct new columns inside the masonry walls to support the new frame. That way you don't interfere with current architecture and be safe on the load path of the new building system. You should be careful with the slenderness of new columns, plus regulations and codes in your area.

Yours sincerely 
Arman

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Arman Tatar S.M.ASCE
Research Assistant
Houghton MI
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First, determine if the existing foundation will support the increase loading and, if not, what can be done to properly found the new loading.
Next, determine if the existing walls are able to support the additional loads. If the existing brick walls are not reinforced, the current applicable building code might require that the existing brick walls be reinforced or have additional reinforcing. The connections of the existing walls might require additional connections to the existing floor and the existing roof to meet current codes. It is likely that the existing roof will need significant modifications or replacement to function as a floor. It might be necessary to sheath the side or sides of the existing walls to provide adequate capacity for the additional compressive or tensile loads. This could be done with welded wire fabric and concrete gunnite, or with fiberglas and epoxy. (Professor Mo Ehsani sells such a product called QuakeWrap.) Another option might be to use reinforced concrete pilasters at the sides or cut into the existing walls. You might need to add steel angle sills bolted to the walls for new connections to the new floor at the top of the brick walls. If the existing roof will be replaced, then the top course might be replaced with concrete with continuous reinforcing that bonds the reinforcing from above and below together.

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Robert Crossno, LMASCE
MASCE-SEI
Albuquerque, NM
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