Shear Wall With Openings Vs. Moment Frame

[ekaj2000]

In terms of determining a Response Modification Coefficient, System Overstrength Factor, and Deflection Amplification Factor for a lateral system where's the cutoff between a shear wall with openings and a moment frame? Is there specific IBC or ASCE language that directs which values to use (i.e. dictates when your system is considered to be a shear wall system or moment frame system), or is it all based on engineering judgement? For example, is a concrete wall with 50% of its area open considered to be a shear wall or moment frame when determining these factors?

 

[haynewp]

Based on ACI definitions of a wall or column, what would you consider the vertical elements at each side of the opening? Also, you will have all those tie requirements you have to fit in the available space if it is detailed as a seismic moment frame.

 

[msquared48]

Ultimately, it will depend on how you intend to reinforce the wall with the opening as to whether you would consider it to be two shear walls or a moment frame.

Mike McCann
McCann Engineering