Drag Struts and Perforated Shearwalls

[medeek]

Would the collector force diagram be the same for a wall that is treated as a perforated shearwall vs. a segmented shear wall?

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[mike20793]

Yes, if the length of the collectors are the same.

 

[KootK]

I vote no. With the perforated shear wall method, shear resistance is applied to the collector between full height piers. That's not the case with the segmented approach. That distinction should result in at least subtly different collector force diagrams 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.

 

[medeek]

I guess my next question would be how to draw the collector force diagram for a perforated shear wall. So far all I have found are examples for segmented shearwalls.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[KootK]

I wasn't able to find any specific examples either. Granted, I didn't look too hard. I think that the rational approach would be to assume a uniform distribution of shear wall resistance across the length of the wall assembly. I very much doubt that's how things shake out in reality given relative stiffnesses of the segments etc. However, I think that's the only model consistent with a shear wall panel with tie downs located only at the far ends of the wall assembly.

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.

 

[medeek]

A uniform distribution would mean the unit shear of the perf. shear wall would match the unit shear distribution of the diaphragm collector, the net unit shear would be zero and hence the collector forces should be zero.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[medeek]

I reality it is probably going to be somewhere in between this theoretical "zero" and the values that would be given if it were analyzed as segmented, just not sure how to quantify it.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[medeek]

On a similar note what should the collector force diagram for a FTAO shearwall look like, similar situation to the perf. shearwall I would think but slightly different.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[KootK]

I agree with your last three posts Medeek. In practice, I'm pretty conservative with my collector designs because of precisely the uncertainty that we've been discussing in this thread.

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.

 

[medeek]

I think the conservative thing to do would be to analyze both FTAO and PERF shearwall collector forces as if they were segmented. Problem solved.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com