CONCRETE MOMENT FRAME RETROFIT

[samnisus]

This is about an existing three story concrete moment frame building. The beams and columns are not adequate to handle the seismic forces. I need design references and any guidance on Jacketing of columns with 1. Concrete, 2. Fiber. Also, how do I retrofit beams. Appreciate in advance any help that you can give me.

 

[shchao99]

You can take a look at:"Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures: by ACI committee 440

 

[aurelio]

Don't lost the alternative with steel sheets and WF or other steel sections.

 

[ishvaaag]

Don't forget to check if the addition of RC shear walls is the way to go. Normally it may limit the deformation to so low lateral deformation that your problem may entirely disappear.

 

[shemp]

FEMA 172 - "NEHRP Handbook of Techniques for the Seismic Rehabilitation of Existing Buildings" has a good summary of many types of potential retrofit methods. FEMA 273, "NEHRP Guidelines for the Seismic Rehabilitation of Buildings" can be followed for the actual design.
FEMA 172 shows a diagram of a beam being jacketed by reinforced concrete. This would probably be very difficult to actually implement b/c of all of the conflicts with architectural items. You would also have to drill holes in the slab in order to get the beam's new stirrups to "close."
Putting in shear walls would seem to be the simplest method to me. But, you also have to watch out because shear walls are not as ductile as moment frames and thus the seismic forces will be larger. Also, extra foundations will be required.