Plate in RISA and reinforcement for it
Plate in RISA and reinforcement for it
(OP)
I modeled shear wall with openings in RISA as number of concrete plates. I got results as plate forces and stresses.
How can I determine required reinforcement based on this information?
Thanks for help.
How can I determine required reinforcement based on this information?
Thanks for help.






RE: Plate in RISA and reinforcement for it
Hence, first locate the areas where you have such tensile stresses, in both horizontal and vertical directions. There you have to place -and in duly form beyond anchor- rebar enough to meet the tensile forces. To ascertain what is the rebar requirement, you must integrate along the thickness and width (or height) the stresses, then you have the force. Sigma x and sigma y give you this. Give also a look to the shear stresses, tau xy; if the stresses are as small as to be easily taken by the concrete, add nothing. But if tau xy cannot be assumed be resisted by the shear strength of the concrete itself, you may either integrate them along a section to give in the same way a shear requirement, that you can reinforce usually as a beam, or you can directly reinforce for the shear stress in place using shear-friction (or shearing surface) concepts. Of course being integral concrete you may be quite confident on the friction factor, between the biggest in the various tables.
So add whatever the shear stresses considerations has produced.
If you had followed in its direction the principal stresses for reinforcement, only the tensile rebars -that may be needed anyway in the 2 orthogonal directions if both principal stresses are tensile- would be needed and no shear consideration (other than any mandated in the codes) would be required. But since you are considering its tensorial equivalent in the xy directions, the shear stresses components needs be also considered.
This said, one needs not to forget in the procedure the usual understandings of the trade. That is, you preferably detail the links as recommended for shearwalls with holes, and of course try to provide regularity in the reinforcement, plus check you meet the minimum geometrical requirements for the kind of structure.
RE: Plate in RISA and reinforcement for it
What you do, is set up your model to ensure that your local x and y axis all are oriented in the same directions. Get your graphical output (colored contours) for the three moments.
The design moment is the factored moment Mx + Mxy in one direction and My + Mxy in the other.
RE: Plate in RISA and reinforcement for it
RE: Plate in RISA and reinforcement for it
for the particular case of a shear wall it won't have very significant flexure of any of the component plates. Hence reinforcing using the moments won't represent properly the rebar needs. I directed my answer to the stresses that may be significant to the case.
Your comment more readily applies to models where the plates are components of slabs mainly subject to loads orthogonal to the plane of the plate, where bending is very significant, i.e., mats, floors or roofs. But loads for shear walls use to come in the plane of the shear-wall.