Hello friends. I want to ask you a question about a topic. As you know, in this latest earthquake regulation, it has been made obligatory to make hollow blocks with curtains. In other words, since the shear force cannot be met by columns in hollow floor slabs, we now provide this with curtains. But here's the thing. Most of the hollow blocks built before this regulation do not have curtains. Now my question is, can we do performance analysis according to the new regulation on such buildings? If we do, what should we choose the coefficient of R. Should we choose the system limited or mixed? Thanks for your answers in advance. Have a nice day.