huangyhg

brick veneer - maximum heights
are there maximum allowable heights specified in code for brick veneer backed with concrete or cmu? aci-530 gives a maximum height of 30' for wood and steel stud backing, but does not specifically call out concrete or cmu requirements.
we have a block and plank project where the client wants to run the brick veneer up 7 stories. how do you recommend detailing this? using an angle at each floor.. every two floors? if following the 30' limit for wood/metal i suppse you could at least go 3 stories.
brick veneer has always been a 'gray' area to me. is this something structural engineers typically detail on their construction drawings? we show typical steel lintel details for the brick support above openings and offer an extra forming in the footing for the brick ledge, but usually the masons, gc, product specs, and arch handle the rest. what is everyone else doing on this?
i apologize if this topic has been previously discussed. i've reviewed several threads discussing similar topics, but haven't been able to find exactly what i'm looking for.
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seven stories of brick veneer without an intermediate suoort (soft joint) is asking for problems (water penetration/leakage and mold).
brick has a long term expansion while most other materials have long term shrinkage due to loads/conditions or creep/shrinkage so there is a potential for differential movement.
this is usually exhibited by shrinkage/creep problems at openings that are tied to the structure, while the veneer may grow. concrete and cmu structures are more stable than wood, so the specificaion is conservative.
if you are going 7 stories, it would be wise to follow the aci guidelines since 7 stories of brick can grow a significant amount that is compunded by the creep of the structural system.
dick
you definitely need to provide shelf angles to support the brick veneer. if you have low floor to floor heights 8 to 10 feet, perhaps you could go every other floor but if higher, i would provide an angle at each floor.
work with the architect to find out what kind of detail he plans on using: notched brick above or below the angle or none.
as dick said brick grows vertically due to moisture whereas block shrinks vertically. this can cause serious problems unless you provide shelf angles to relieve these built up stresses.
in addition to the shelf angle, you need a space below it to allow for movement.
i also limit the length of the shelf angle due to exterior exposure and thermal movement.
dik
agree with jike. if you have 10' floor to floor, you could probably go 2 stories at a time. if your floor to floor heights greater than say about 12 feet, i would put a relief angle at evey floor.
this is definately a subject i get extensively involved in as the structural engineer on a project. brick expansion is not a subject to be taken lightly, and to be honest, most architects do not do a very good job of properly detailing brick to accomodate its movement. it usually up to me to remind them of even basic things like incorporating brick expansion joints in walls, need for relief angles, detailing corners to allow for the expansion of the brick in two directions, etc.
nyc building code ( since 1968) has a requirement for horizontal expansion "soft" joints spaced at 30 feet on center.

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