Tilt Up Response Modification Coefiicient

[bar7h]

I need some input on the appropriate 'R' value to use in concrete tilt-up design. Under the 2003 IBC we used R=5.5 for special reinforced conc. shearwalls. Under the new 2006 IBC & ASCE 7-05, Table 12.2-1 lists intermediate precast concrete shearwalls with an R=4 and special reinf. conc. shearwall with R=5. My understanding is that some building officials are requiring the use of R=4, however, I feel that and R=5 is justified if the walls are detailed as special. Any input is appreciated. Thanks.

 

[JAE]

Check out this article in Structure Magazine from January, 2008. I think it is exactly what you are asking about.

http://www.structuremag.org/Archives/2008-1/C-StructPract-Steinbicker-Jan08.pdf

 

[bar7h]

Thank you. That was very helpful.