## Question

**I have a question about how to determine the response modification factor using Pushover analysis.**

**We are conducting a stability assessment for an existing building. The existing building is a typical moment frame with a response modification factor (R) of 3.0, and the additional part being added to it is a shear wall structure.**

**When a general analysis is performed on the existing building with a response modification factor of 4.5, the bottom shear force is approximately 4200 kN, and when a response modification factor of 3.0 is applied, the bottom shear force is approximately 6300 kN.**

**When we performed Pushover analysis on this building, the bottom shear force at the performance point was 3670 kN. In this case, can we select a retrofit element by applying R=4.5 based on the fact that the bottom shear force obtained from Pushover analysis is close to the bottom shear force obtained when R=4.5 is applied? When R=3.0 is applied to a typical moment frame, there is concern that too many seismic retrofit elements will be required.**

## Answer

**Simply put, you cannot determine the response modification factor based solely on the bottom shear force at the performance point.**

In Pushover analysis, assuming that the Capacity Curve is well-defined, you can evaluate the building's elastic performance based on the ratio of dmax (the displacement at the point of failure) to dy (the yield point displacement) and this ratio (dmax/dy) can be used to assess the building's ductility.