Deflection of Concrete Shear Walls

[abusementpark]

How do most of you guys compute deflections for concrete shear walls?

The things I am particularly curious about is how you account for:
- Shear Deflection
- Reductions in stiffness after tensile cracking has occured.
- Non-linear behavior of the wall.

Obviously for low, squat shear walls, deflection is most likely not a design consideration, but at some point it must become necessary the get a fairly accurate representation of the deflection.

 

[msquared48]

In that the deflection is directly related to the stiffness used in the lateral design of a shear wall systerm design with a rigid diaphragm, I would be concerned (if there is a rigid diaphragm).

Otherwise, with a flexible diaphragm, and a short stubby wall, I would have to agree.

Mike McCann
MMC Engineering

 

[ishvaaag]

I think the biggest problem with this is that cracked stiffness vary along the member and with every hypothesis so the best thing would be that the program being used would be following it, maybe with reasonable fragmentation in segments. Yet I don't think most programs are doing nor am able to do this. Maybe RAPT can do this.

I will quote 4 references in PCI Jurnal of the times I was buying this kind of info:

A design procedure for partially prestressed concrete beams based on strength and serviceability, Inomata, PCI JR 266

Creep and shrinkage haracterization for analyzing Prestressed concrete structures, Bazant&Panula, PCI Jurnal May-June 1980

Prestress Loss and Deflection of Precast Concrete Members, Tadros, Ghali, Meyer, PCI JR 308.

Serviceability design of continuous prestressed concrete structures. Elbadry-Ghali.

This last is maybe the best for the concepts to be implemented when accounting for deflections in PC elements.

I think it was this that had a DOS program author Ghali sent to me for free from Calgary, Alberta, Canada, thanks again for that, was a nice program.

Then the PCI Handbook, I have th 4th edition, treats in chapter 3 the cases with stiffness reduction in ACI way, but at least you can easilty follow the (to PCI) relevant steps.

 

[abusementpark]

Thanks for the references, that's a start!