A novel crosswind mitigation strategy for tall buildings using negative stiffness damped outrigger systems

Abstract

Summary This study presents a new crosswind mitigation strategy by using negative stiffness damped outrigger (NSDO) system for tall buildings. Using the “assisting motion” feature of negative stiffness, NSDO amplifies the motion of viscous damper resulting in and significant improvement of energy dissipation for tall buildings. Systematical evaluation and comparison on crosswind performance are carried out for tall buildings using (a) conventional outrigger (CO), (b) conventional damped outrigger (CDO), and (c) NSDO. It is shown that the proposed NSDO is able to achieve a damping amplification factor larger than a unit, which would never be achieved by CDO in practical due to the actual deformation of perimeter columns. In this way, NSDO has the most satisfactory crosswind reduction effect, especially when perimeter column stiffness is insufficient. For example, replacing CDO with NSDO not only attenuates crosswind‐induced harmful drift and structural acceleration by 22% and 36%, respectively, but also further saves about 75% of the size of viscous dampers. In other words, NSDO adopts less outrigger damping coefficient but reduces more crosswind‐induced vibration.

Design of Optimal Passive Tuned Mass Damper with Static Output Feedback and Updating Iterative Procedure

“…Te structural damping ratio of 0.01 is assumed for each mode under wind loads. For more details on the outrigger building, readers are suggested to refer to Chang et al [45] and Wang et al [9,46]. Te Davenport wind spectrum of the outrigger building was evaluated by Wang et al [47].…”

Frequency independent damped outrigger systems for multi‐mode seismic control of super tall buildings with frequency independent negative stiffness enhancement

“…By utilizing the motion assisting feature of NSD, the motion and dissipation of viscous damper will be significantly amplified, resulting in considerably damping effect even when the column/outrigger stiffness is inadequate. 21 For example, previous result indicated the NSDO is able to realize an over 30% damping ratio for the fundamental mode of tall buildings as compared with a CDO, whose maximum damping ratio is less than 5% no matter how much outrigger damping is applied. 7 For determined position and column/outrigger stiffness, the outrigger damping coefficient has an optimal value for each mode to make the modal damping ratio maximum.…”

“…[11][12][13][14][15] To enhance the performance of conventional damped outrigger (CDO) systems, various other types of devices like metallic dampers, 16 magnetorheological dampers, 17 shape memory alloy damper, 18 and inerter dampers 19,20 were developed to replace the viscous damper in CDO. Among them, the negative stiffness damped outrigger (NSDO) 7,21,22 was proposed by the authors to solving the damping limitations faced by CDO with inadequate column/outrigger stiffness.…”

“…Typically, in terms of the application in tall buildings, NSDO combined viscous damper and NSD at outrigger ends, and the NSD is basically in series with column/outrigger. By utilizing the motion assisting feature of NSD, the motion and dissipation of viscous damper will be significantly amplified, resulting in considerably damping effect even when the column/outrigger stiffness is inadequate 21 . For example, previous result indicated the NSDO is able to realize an over 30% damping ratio for the fundamental mode of tall buildings as compared with a CDO, whose maximum damping ratio is less than 5% no matter how much outrigger damping is applied 7 …”

Effectiveness and robustness of braced‐damper systems with adaptive negative stiffness devices in yielding structures

“…Various passive negative or pseudo-negative stiffness devices were proposed and tested. [24][25][26][27][28][29][30][31][32][33][34] The superiority of negative stiffness was also recognized in many civil engineering applications including based isolation, 29,35,36 stay cables, 32,33,37 apparent yielding, [25][26][27][28][29][30] damped outrigger, [38][39][40][41] and tuned mass damper [42][43][44] etc.…”