Seismic Response Assessment of Twin Tower Structures with Different Height Formations

Twin high-rise buildings connected by structural links behave differently from isolated towers when they are exposed to earthquake excitation. Their proximity and interconnection cause the two buildings to vibrate as a coupled system, making seismic performance dependent on tower height, connector behavior, stiffness distribution, and dynamic characteristics. This study evaluates five twin-tower arrangements, identified as Cases A to E, for Seismic Zone V conditions in accordance with IS 1893:2016. Response Spectrum Analysis was used to compare the models in terms of lateral displacement, base shear, natural time period, mass participation, and internal actions in columns and beams. The results indicate that Case E is most effective in limiting displacement and reducing vertical force demand, whereas Case D provides better behavior for base shear control and torsional response. These outcomes agree with previous studies emphasizing the need for efficient inter-tower connections, reliable analytical modeling, and appropriate foundation systems in earthquake-resistant high-rise design. The tabulated results and graphical outputs support comparison among the alternatives and point toward further research for improving the seismic reliability of coupled tall buildings.

Keywords: Coupled Twin Towers, Response Spectrum Analysis, Earthquake Performance, Structural Links, Tall Building Systems