Shear Wall Openings
Shear Wall Openings
(OP)
I have a question about concrete shear box walls.
It is common for concrete shear boxes to be used as elevator shafts in multi-story building. Unlike single, isolated shear walls, the walls in the box that are perpendicular to the load are used as flanges and they take the compression/tension forces. The walls in the box that are parallel to the load must take the shear, similar to a beam web.
My question is with regards to the walls that are parallel to the load and must take the shear force. How do you analyze what is happening with the shear forces around the openings? At each floor there has to be openings for elevator or stair entrances.
What do engineers typically do analyze what is happening and how these local regions need to be reinforced?
It is common for concrete shear boxes to be used as elevator shafts in multi-story building. Unlike single, isolated shear walls, the walls in the box that are perpendicular to the load are used as flanges and they take the compression/tension forces. The walls in the box that are parallel to the load must take the shear, similar to a beam web.
My question is with regards to the walls that are parallel to the load and must take the shear force. How do you analyze what is happening with the shear forces around the openings? At each floor there has to be openings for elevator or stair entrances.
What do engineers typically do analyze what is happening and how these local regions need to be reinforced?






RE: Shear Wall Openings
"a coupled shear wall is a continuous wall with vertical rows of opening created for windows and doors, coupled by beams that interconnecting the blade walls across the openings. The connecting beams are referred to as coupling beams. It may be shallow or deep beam type, however the most common type used is a deep beam type. Coupling beam has adequately strong and stiff under elastic loading, ductile and able to dissipate energy under inelastic loading.
The coupling beams in between are actually constraint the walls to deflect similarly and will be subjected to flexural and shear combined. When shear blade walls are interconnected by a system of beams or slabs, the total stiffness of the system exceeds the summation of the individual wall stiffness because the connecting slab or beam restraints the individual cantilever action by forcing the system to work as composite unit. This type of system can used economically to resist lateral loads in buildings up to about 40-stories."
Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that them like it
RE: Shear Wall Openings
In the other direction is where the coupling beams occur which RE refers to above. These beams have the effect of making the channels on each side work as push-pull members, with the coupling beams up the height of the building serving to transfer the load across. The design and detailing of these beams is a critical element in high rise cores, as the reinforcement is congested where the beam bars enter the wall.
RE: Shear Wall Openings
Shearwalls may well work in single curvature along the very tall heights of important buildings, or if in double curvature, the lengths between inflection points can still be awesome. The weak axis bend buckling of the proportionally thin shearwalls then becomes paramount, and also bracing against it. So you need to prove yourself that this overall bend buckling behaviour has been properly counteracted upon by other concomitant structural schemes present, and you do it by analyzing with P-Delta and seeing drift deformation converge to acceptable limited values i all directions.
AFTER that you may start thinking of shearwall panels or elements in what you will have to follow the stresses present, and if taking the form of some beamcolumn or beam, also follow the recommendations for such for the specific use.
RE: Shear Wall Openings
Do you use ETABS? Modelling these "parallel" zone as spandrells and detail as a coupled shearwall would be the answer. If you dont use ETABs or similar programs the calcs involved in this excercise would take some time to do. Depending on your "lintel depth" you would be going from either a hori beam coupled beam or an "X" type detail would be required at the worst case of which would require some SW space/room!
Keep your openings less than 5% of overal gross face area.
RE: Shear Wall Openings