Hi all! Can you please help me to understand the behavior of gravity columns in seismic event?
After reading section 18.14 of ACI, I understood that it is okay for gravity columns to go to yielding under seismic event. If the demands on gravity columns exceeds the capacity during seismic event...
We donot design the gravity columns for the forces induced by lateral seismic load, correct? But we have to ensure we provide the detailing as per section 18.14 of ACI so that columns maintain its integrity during seismic event.
Yes, columns are not the part of lateral load resisting system. So do you mean only the vertical component of seismic component should be considered for the design?
Hi all! Do we design the gravity columns using the load combinations that have seismic component in it? Aren't the gravity columns are designed to resist gravity loads only? Can you please make the concept clear for me?
I saw following load combinations being taken for the design of gravity...
Hi all! I am running into an error message while performing modal analysis using ritz vector. Please see attached image. My model works fine if I switch to eigen vector. Can you please help me understand what is the error here and how can we debug?
Thank you all for useful information. I haven't understood the behavior of gravity columns during seismic event. What kind of gravity column behavior we expect during seismic event? Of course they won't be designed for high forces that will be induced during the seismic event. Gravity columns...
Hi all! Can you please help me understand the section 18.14 of ACI (Members not designated as part of the seismic-force-resisting system)?
Section 18.14.2.1 tells you to apply gravity load and design displacement. For the gravity columns, in computer model we will have pinned at the ends. This...
Hi! I am applying a response spectrum along x direction (RSX). The diaphragm should have the chords shown by black arrow but if I checked the sign of resultant forces both are positive. If I was applying ELF it matches the sign convention. I am not understanding why is this happening for the...
Thanks all!
@Athalus-> I heard this for the first time. If force is transferred for joist to deck does the deck has enough shear capacity in the direction perpendicular to the ribs to withstand the diaphragm shear generated?
Can you please provide reference to this concept if you know any?
Hi all! I am trying to understand the diaphragm behavior for bare steel deck supported by joist (let's say at 6 ft o.c) on perpendicular direction. I think when structure is laterally loaded, deck should be provided with sufficient shear strength to resist the shear stress generated on diaphragm...
Hi all! My structure has precast sandwich wall (insulation in between two concrete walls) for lateral force resisting. How do you guys model this wall appropriately in ETABS? Any suggestions will be greatly appreciated?
