Use of Unreinforced brick masonry in seismic design
Use of Unreinforced brick masonry in seismic design
(OP)
I have a project in where we are proposing to add one story to an existing three story building. We are also enlarging the building laterally. The existing structure predominently consists of steel framing but there is a rebust brick masonry bearing wall that runs through the middle of the building. Our lateral design includes the addition of steel moment and braced frames for the new structure and retrofitting braced frames within the existing structure. My question is, can we consider the existing brick wall to contribute to resisting the lateral forces (wind and seismic)?






RE: Use of Unreinforced brick masonry in seismic design
So I'd say unless you can show that the wall meets the requirements of new code I wouldn't use it as part of the lateral system. You may want to isolate it from the diaphragm in-plane so that it does not take seismic loads as well.
RE: Use of Unreinforced brick masonry in seismic design
Could you remove it?
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Use of Unreinforced brick masonry in seismic design
RE: Use of Unreinforced brick masonry in seismic design
Had to mix concrete shear walls and moment frames in the lateral system of a hospital for an expansion many years ago. You could always perform the lateral analysis based on relative rigidities, but this would put you back where you were in the beginning, having to upgrade the wall.
Frankly, if this is a multi-story brick bearing wall, possibly with let-in wood joists to either side, I have no idea how you could effectively and economically isolate the wall seismically from the rest of the structure.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Use of Unreinforced brick masonry in seismic design
RE: Use of Unreinforced brick masonry in seismic design
RE: Use of Unreinforced brick masonry in seismic design
RE: Use of Unreinforced brick masonry in seismic design
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Use of Unreinforced brick masonry in seismic design
RE: Use of Unreinforced brick masonry in seismic design
If the wall is isolated then I would treat it as a stand-alone element which should have the integrity of resisting it's own mass in a seismic event.
Either way, I would assume the wall would have to be reinforced unless damage to the wall is of no consequence to personnel safety, structural integrity of the system or anticipated cost of repair.
RE: Use of Unreinforced brick masonry in seismic design