Masonry Shearwall "Rw" 1

[WAstruc10]

For design of reinforced masonry shearwalls, UBC97 Sec. 2108.2.5.6 references "Rw" = 1.5. What is this? A remnant from the 94 UBC? It is not listed as a variable, as far as I have seen. How should one apply it to boundary member design? Regards,

 

[Taro]

Per the January 2001 errata, it should be revised to "R equal to 1.1". You can download all the errata from:

http://www.iccsafe.org/cs/codes/errata.html

 

[WAstruc10]

Thank you for the clarification, Taro. On a related subject, can someone explain how to apply Section 2108.1.4.3.2: "The value of phi may be 0.80 for any shear wall when its nominal shear strength exceeds the shear corresponding to development of its nominal flexural strength for the factored-load combination." I can calculate a "nominal shear strength," but the other half of this comparison is quite confusing. Thanks again.

 

[Taro]

Draw a free body diagram of the wall pier showing the moments and shears required for equilibrium. For single story cantilever piers, the shear will be V = M/h where h is the pier height. For single story fixed piers, the shear will be V = 2M/h. For multi-story piers, it's a bit more complicated, but you can figure it out with the free body diagram.