Modelling/Design of Tilt-Up Shearwalls to Canadian Standards

[jahoel1400]

Hello all, long time lurker here.

I work in Western Canada and have need to design roughly 50 unique tilt-up wall panels for gravity and seismic shears.

Softwares that do this (Tekla, for example) don't seem to offer Canadian codes. My firm is thinking of using ETABS for this, with the proper resistance factors. However we have limited experience with the program. For this I was thinking of modelling each panel without edge constraints, meshing, and then creating a fine mesh at embed plate locations which would then have edge constraints applied locally to simulate the embed plate local forces.

I would like to see how many engineers agree with this

Can anyone provide me with tips on how best to go about this?

 

[KootK]

I'm also in western Canada and also have had some exposure to tilt-up work there:

- Within reason, I actually use US codes here for some things. I'd need to explore it a bit but I'm not sure that the use of software not dealing in CSA is entirely out of the question, particularly if you have programmatic access to load factors etc.

- Your approach sounds clever and well thought out. My two concerns would be a) can you get enough fee to survive expending this level of effort and b) can ETABS handle the out of plane design of slender walls or would you be force to run two design models in parallel using additional software.

- Accurately designing tilt up wall systems for in plane loads is a pretty complex problem for the street side walls which usually have gobs of openings and plan jogs. I favor the use of design methods that are as simplified as possible, even if accuracy is questionable. One strategy is a bracketing solution where you design the punched walls for a uniform distribution of diaphragm shear over the length of the building and then design the solid walls for a distribution based on expected panel stiffness.

- As you probably know, software like StructurePoint and Eriksson Wall do a good job of out of plane wall design but don't do much for in plane wall design. Designing panels for slender wall axial loads arising from lateral environmental loads concurrently with gravity is not something that's handled especially well within the industry in my opinion.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.