the performance of building with infill wall

[maktrb]

I modeled a three-storey building with/without infill-wall. In the model without infill-wall, damage occured to the elements regardless of the damping type. In the infill-wall model, if the damping type was set to "none", the elements were damaged. However, when I selected the damping type as "stiffness-proportional damping", no damage occurred. I think that this was odd for near-fault earthquake records. I think there was a problem related to my modeling. I submitted my models on the link.



https://drive.google.com/file/d/1EGbe6Q ... sp=sharing

[maktrb]

Could you help me if there is a problem with the model?

[huffte]

Hi maktrb. I downloaded your archive and tried to extract the files therein. I received the message 'archive is unreadable'.

[maktrb]

Dear huffte;

I'm sending files again.

https://drive.google.com/file/d/1muTxnr ... sp=sharing
https://drive.google.com/file/d/1VWh_R8 ... sp=sharing

[seismosoft]

The fact that you specify damping in your model means that the earthquake motion is damped and smaller seismic deformations occur. Hence, it is not unreasonable that you get lower damage with the damped model.

Seismosoft Support

[maktrb]

There is no problem with the bare frame system. In the frame system with infill walls, even if the column dimensions are 25cmx25cm, no element was damaged. The fact that no damage occurs even in the weak column-strong beam behaviour suggests that there may be a modeling error.

[huffte]

It is difficult to determine exactly what you are asking, maktrb. Your initial post stated that the bare frame fails. Your most recent post states that there is no problem with the bare frame. With infills, aren't the infills taking most of the load rather than the rigid frames? I assume the stiffness of the infills is much larger than the stiffness of the moment frames. Which elements are damaged in the two cases?

[maktrb]

Thank you for your answer. In my second e-mail, I tried to support my first e-mail. I tried to state that there was no modeling error in the bare frame system.

In the frame system with infill walls, there was no damage in the columns even when the ground floor infill wall is removed. Therefore, the absence of damage to the frame system with infill walls cannot be explained by the stiffness of the infill wall. I think there's another problem I don't know.The new model is given in the following link.


https://drive.google.com/file/d/1pWsKIy ... sp=sharing

[huffte]

It's an interesting problem, maktrb. The first thing I observe in examination of the settings is that you are using initial-stiffness-based damping and have specified 4% damping at a period of 0.30 seconds. This means that the effective modal damping, as a percentage of critical, for the bare frame is likely significantly lower than that for the infill frame. Yes, the damping coefficient is higher for longer period, but the percent of critical damping is inversely proportional to period. So, by specifying 4% at 0.30 seconds, you get significantly less than 4% for any period longer than 0.3 seconds.

It might be interesting to do an eigenvalue analysis for each of the two cases, infilled and bare, to enable tweaking of the damping parameters in the analyses. That is just one suggestion. I am sure others may be necessary to pinpoint the behavior you wish to model.

Best of luck in your work, maktrb.