In big cities, industrial facilities, refineries, powerhouses and oil platforms, there are lots of adjacent structures that are connected by at least one connector. The damper is used as a useful tool to connect the structures. Many researchers have investigated the seismic behavior of connected structures using damper in their studies. The presence of a centralized damper at the junction between two constructions changes connected sets into non- Keywords Connected structures, Separate dynamic analysis, Classical and non-classical modal analysis, Non-classical damping, R