Random seismic response analysis on damping performance of multiple damped outrigger structures incorporating negative stiffness devices

In response to the restriction of the maximum additional damping ratio caused by the limited stiffness of the perimeter columns in the conventional damped outrigger (CDO) structure, the concept of negative stiffness damped outrigger (NSDO) is proposed which introduces the negative stiffness device parallel with the damper. It has significant advantages in reducing the cost of damping and controlling the wind-induced vibration and seismic response of the structure, which is a novel idea of vibration reduction for high-rise buildings. In this paper, the analysis model of the multi-outrigger structure is established based on the continuous Timoshenko beam, and the state space equation of the structure-outrigger is established by the virtual small mass method. Finally, the random seismic response of the system is obtained by solving the Lyapunov equation. Taking the structure with two outriggers as an example, the parametric analysis of the random seismic response of the structure with two NSDOs (2NSDO) and the hybrid outrigger structures with two layout schemes are carried out. The results show that the seismic performance of the reasonably arranged NSDO structure is better than that of the CDO structure. The inter-story drift decreases from 0. 68 times to less than 0. 25 times of the uncontrolled structure (only the core tube), the harmful inter-story drift decreases from 0. 71 times to 0. 4 times, and the acceleration, base shear and bending moment all decrease from about 0. 7 times to 0. 5 times. Compared with different NSDO arrangement forms, the 2NSDO structure and the hybrid outriggers structure with a lower conventional outrigger (CO) and an upper NSDO (1CO + 1NSDO) have significant control effects on the indexes of harmful inter-story drift, acceleration, base shear and bending moment, which can be reduced to 0. 55 times. The hybrid-outriggers structure with a lower NSDO and an upper conventional outrigger (1NSDO + 1CO) can reduce these indexes to 0. 82 times. For the inter-story drift, the 2NSDO structure can reduce to about 0. 25 times, and 1CO + 1NSDO and 1NSDO + 1CO can reduce to 0. 3 and 0. 4 times, respectively. In terms of the seismic performance and the influence on the static stiffness of the structure, 1CO + 1NSDO is more recommended in engineering. © 2024 Science Press. All rights reserved.