Performance of Connected Buildings Under Parameter Uncertainty Subjected to Random Earthquakes

Interconnecting adjacent buildings by damper is established as a viable technology to avoid pounding and resulting damages observed in the past major earthquakes. Performance of such system has been investigated in the past. However, all these studies assume the system parameters as deterministic. It is well established that performance of a control system can significantly get affected by the presence of uncertainty in system parameters. In this study, the effect of parameter uncertainty is included in the stochastic response evaluation of the connected buildings under random earthquake. The buildings, modeled by two single degree of freedom systems (SDOF), are connected with nonlinear hysteretic damper. The stochastic uncertainty in the system parameters is dealt with matrix perturbation theory, using first-order Taylor series expansion. The total probability concept is used to evaluate the unconditional response of the structures under parameter uncertainty; for this, the conditional response and its sensitivities are evaluated in the random vibration framework. The efficiency of the connected building system is demonstrated in terms of substantial reduction of the seismic responses. The efficiency, however, varies drastically in the presence of uncertainty. The disparity among the displacement could be as high as 5–10% with and without considering uncertainty. Neglecting uncertainty underestimates the response for flexible structure, whereas overestimates the response for stiff structure, which might lead to unsafe design for the flexible structure provided that uncertainty is not adequately taken care of. Displacement, acceleration of the flexible building, and acceleration of stiff building show coefficient of variations around 10%, which is remarkably amplified (as high as 50%) in case of the displacement of stiff building. The findings establish the importance of parameter uncertainty on the performance of the connected buildings.