Stiffness, Rigidity on ETABS

[jenofstructures]

I manually computed the Rigidity and stiffness of shear wall then doing a simple model of it on ETABS. I can't produce the Vu that i got from computing it manually. I don't know how to check if where did i go wrong in my calculation because i can't see the calculated deflection of ETABS, its k, and R.

Where can i find these values?

thank you in advance!!!!

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds

 

[slickdeals]

Are you doing an analysis on a structure or just a wall?
ETABS does not report the stiffness value. You can apply a point load, take a look at deflection and then back track the stiffness used. Remember to account for shear deformations in short squat walls. If your wall is tall and slender, you can neglect shear deformations and calculate stiffness based only on flexural stiffness.

Vu should not change based on stiffness for a single wall. If you have multiple walls, then maybe the distribution is different.

Need more info to give a better answer.

 

[jenofstructures]

I modeled a simple wall with an opening

about 9ft wide and 5ft tall with an opening at the middle length measures 2.5ft x 5ft

Then I used a Pier labeling for this and the wall had a 0.58 kips of Vu

When i computed the wall the Vu supposedly 0.3722 on upper part of the wall and Vu of 0.104kips on each pier in left and right.

But the Etabs gave a Vu of 0.58 (equal to the given shear) on the upper part wall, and 0.107 kips on left pier then 0.475kips on right pier

when i said upper wall it means the spandrel that measures 9ft wide and 2.5ft tall then the left and right pier are 2ft wide and 2.5ft tall.
by the way the wall is 8" thick.....

Why is that happening?

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds

 

[slickdeals]

Upload your model. It could have something to do with the meshing. Or probably because you applied the load at the right of the model, and due to some meshing inconsistency the load was being picked up by the right pier (unlikely), but can't be sure without seeing the model.

 

[jenofstructures]

here's the model i made

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds

 

[jenofstructures]

here's the manual calculation

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds

 

[chazcy]

I'm a new user of ETABS. I used ETABS software for almost two months. So guide me if I'm not in the right track.

I'm interested for this one. I will verify the result in hand calculation and on ETABS also to find out where you get wrong. Meshing inconsistency is not the problem here i think because when I attended a seminar @ Asian Institute of Technology (AIT-Thailand),a partner of CSI (developer of ETABS) they discuss about meshing, that meshing in ETABS is automatically done by the software internally. So meshing is not a big problem i think.

If so is the problem why we are using that software in a small scale model where hand calculation is more faster in solving like so.

"Imagination is More Important than Knowledge"

 

[jenofstructures]

the meshing is happened internally on some elements like on Membranes

Poems are made by fools like me, but only God can make a tree. engineers creates wonderful buildings, but only God can creates wonderful minds

 

[stressed]

Base shear matches perfectly at 100 Kips for Vu case. You labeled different walls with different pier labels which report results separately. I'm not sure what the problem is.