location of shear wall in multistory building
location of shear wall in multistory building
(OP)
In a 12 Story building with a very irregular grid rectangular in the middle then circular at one end. What are the factors that should be kept in mind when placing shear walls at a certain location in this or any other building?
is there any reference/code stating or justifying the location of a shearwalls in a building.
where should a shearwall be placed in any building?
is there any reference/code stating or justifying the location of a shearwalls in a building.
where should a shearwall be placed in any building?






RE: location of shear wall in multistory building
RE: location of shear wall in multistory building
RE: location of shear wall in multistory building
that is assuming it is a seismic area, if not the ceneter of wind load is more relevant.
RE: location of shear wall in multistory building
At least in the US, everywhere is a seismic area, though..some more severe than others....but your point is a good one.
RE: location of shear wall in multistory building
1) what is "center of loading" ? how do you find a center of loading in a building?
2) i know about center of gravity or mass, but what is center of rigidity ? and how do you find that out in a building ?
RE: location of shear wall in multistory building
For wind:
Say you have a 40 ft. wide building. The wind would typically be centered at 20 ft. from either end and in the center of the wall surface vertically.
For seismic:
For a uniform building shape, each floor's center of mass is located in the center of each floor..assuming all the floor framing is uniform and all the walls are uniform.
If they are not uniformly laid out, then you have to calculate where the center of mass at each floor is:
Σ(weight x distance)
------------------------------------ = dist. to c.m.
Σweight
RE: location of shear wall in multistory building
what is center of rigidity ?
RE: location of shear wall in multistory building
You have to determine the rigidity (kips/inch) of each brace or shearwall line and then find their weighted center, again - in each direction.
RE: location of shear wall in multistory building
RE: location of shear wall in multistory building
If you only have two rows then the horizontal loads are distributed according to simple statics (somewhat akin to a point load on a beam).
RE: location of shear wall in multistory building
RE: location of shear wall in multistory building
RE: location of shear wall in multistory building
RE: location of shear wall in multistory building
RE: location of shear wall in multistory building
I have uploaded the article if you are interested. (Sorry for the picture quality - scan of a copy.)
h
RE: location of shear wall in multistory building
Thanks for that. Restraint is always an important issue. I have not read this particular article, but will do so when I get a chance. Looks like one a lot of people on this site could use, as I have the impression that some think that concrete just cracks for no apparent reason. By the way, and you probably know this, but the reinforcement doesn't "restrain the shrinkage" or prevent cracking, it controls the cracks to an acceptable width.
RE: location of shear wall in multistory building
I did read the article, and it is an excellent, largely non-technical explanation of restraint cracking with a lot of examples. It correctly discusses the problem as being worse in unbonded post-tensioned slabs than in conventionally reinforced slabs. What is not said is that bonded post-tensioned slabs work better than unbonded slabs, but even so, deformed bars are required in many cases for effective crack control.
RE: location of shear wall in multistory building
There is advantages in locating your shear walls (where possible) to correlate with your gravity load structure. By that I mean selecting walls with sufficient compression in them due to dead load / self weight so that overturning moments induced by lateral loading do not result in tension (or very little) across the section. I have found large compression is easier (and more efficient) to handle than large tension.
RE: location of shear wall in multistory building
Where the objective is that center of load should
coincide with the center of rigidity. which is very tricky to do and takes a lot of experienced Engineering Judgement.
we know we cannot in reallity made this perfect,
dont hesitate to do "trial and error" using a good 3d analysis software.
I learned a lot in this thread (thanks to all).
one question....i know it is logical to loose the 5% eccentricity as required by code when your structure is irregular. has anyone tried? coz I havn't.