Analysis of horizontal vibration characteristics of unequal height twin towers of rigid connected structure

• Published in: Journal of Building Engineering 2022-06, Vol.50, p.104146, Article 104146
• Main Authors: Meng, Fantao, Ruan, Xingqun, Zhao, Jianfeng, Qiu, Jiangrui, Meng, Lei, Hou, Peng
• Format: Article
• Language: English
• Subjects: Coupled vibration; Natural vibration period; Rigid connector; Simplified calculating equation; Unequal height twin towers
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2022.104146

The twin-tower concatenated building with unequal height is highly favored by architects, because of its distinctive appearance and specific building function. Recently, the dynamic characteristics and earthquake action of the unequal height twin towers with the rigid connected structures have been assessed utilizing engineering experience and finite element analysis. However, the technical guidance at the theoretical level is rarely reported. Here, to reveal the dynamic characteristics of unequal height twin towers with the rigid connected structures, the equivalent design method for isolated structures was employed. The Higher Tower (S1) is equivalent to a two-particle two-degree-of-freedom system in the unequal height twin towers with a maximum height of 60 m, while the Lower Tower (S2) is equivalent to a single particle one-degree-of-freedom system. The variation law of their first-order natural vibration periods in the parallel conjoined direction was then analyzed using a simplified structural dynamics method. To investigate the coupling of frequencies and changing law of mode shapes, a three-degree-of-freedom system was established in the vertical conjoined direction. The simplified structural dynamics models were compared to the finite element simulation and validated further by an engineering practice. The results indicate that there are numerous plane and torsion coupling modes in the direction of the vertical rigid connection. The equipment and function area with heavy load should be set in the S1 area when the total stiffness meets the requirements in the direction of the vertical rigid connecting body, whereas the stiffness of the S2 should be controlled to the lowest extent. By analyzing engineering examples and comparing them to numerical simulations, the simplified structural dynamics methods can be used to control and optimize the design scheme to determine a reasonable position for the connecting body within the tower height. •the simplified analysis method in structural mechanics was utilized to derive calculation formulae for the first-order natural vibration period along the conjoined direction.•Based on a detailed parametric analysis, the variation law regarding first natural vibration periods was concluded to assist engineering technicians with clear understanding of the “help” effect between two substructures and control over critical parameters.•In the vertical conjoined direction, through parametric analysis on the torsion-transla