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Re: Tilt-up In-Plane Shear

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I don't think your analogy of the SMRF and OMRF is quite applicable here. Those two systems are separated by a huge difference in the base shear that each system is designed for. The design lateral force for OMRF is  more than twice the SMRF (due to the difference in R value). However, the ASD and LRFD design is just a difference in approach ro the design where one method uses stress level and the other uses member capacity. There is no significant inherent overstrenegth necessarily achieved in the ASD verses the LRFD method.
Ben Yousefi, SE
Santa Monica, CA

>>> ASQENGG2(--nospam--at) 06/19/03 10:21PM >>>
I designed a tilt-up shear wall (in-plane shear) using the ASD method.  The consultant plan checker said that I have to meet the requirements of 1921.6 which is a part of Division II ( Strength Design).

It is very clear that at the very start of Chapter 19, Section 1900.3 say that the design of concrete structures shall be in accordance with one of the following methods, which are the LRFD (Division II) and ASD (DivisionVI).  So if you go to Division VI, there is no section in it that referred you back to 1921.6. 

The plan checker of the City argued that 1926.1.2 said that for design of members not covered by this section, appropriate provisions of this code shall apply.  This ambiguous statement is their weapon for me to meet the 1921.6 requirements which I believe is not referring to structures designed using ASD.

My argument is that structures designed using ASD undergo elastic deformation and doesn't need further provisions in order to work.  We need to provide special provision for members designed using LRFD because such structures undergo inelastic deformation.  My analogy to this is like in steel design when using SMRF as against OMRF. SMRF will undergo inelastic yielding while the OMRF act more in elastic behavior (bounce back to its original shape). 

Thanks a lot for any of your comments.

A. S. Quilala Jr.