This paper presents selected results measured from a monitoring system with 30 accelerometers installed at six floor levels in 508-m high Taipei 101 Tower located in Taipei City, Taiwan where earthquakes and strong typhoons are common occurrences. Emphasis is placed on analyzing the data recorded during three typhoons ͑Matsa, Talim, and Krosa͒ and a seismic event ͑Wenchuan earthquake occurred on May 12, 2008 in Shichuan, China͒ to investigate the effects of wind and seismic on the supertall building. Dynamic characteristics of the tall building such as natural frequencies, mode shapes, and damping ratios determined from the measured data are presented and compared with those calculated from the finite-element model of the high-rise structure. The seismic performance of this supertall building to a long distance earthquake ͑Wenchuan earthquake͒ is assessed based on the field measurements and numerical analysis. The findings of this study are expected to be of considerable interest and practical use to professionals and researchers involved in the design of supertall buildings.

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This article presents a Kalman‐filter‐based estimation algorithm for identification of wind loads on a super‐tall building using limited structural responses. In practice, acceleration responses are most convenient to be measured among wind‐induced dynamic responses of structures. The proposed inverse method allows estimating the unknown wind loads and structural responses of a super‐tall building using limited acceleration measurements. Taipei 101 Tower is a super‐tall building with 101 stories and a height of 508 m. Field measurements and numerical simulations of the wind effects on Taipei 101 Tower are conducted. The wind loads acting on the super‐tall building are estimated based on the wind‐induced responses determined from the numerical simulations and the refined finite‐element model of the structure, which are in good agreement with the exact results. The stability performance of the proposed algorithm is evaluated. The influence of noise levels in the measurements and covariance matrix of noise on the identification accuracy are investigated and discussed based on the L‐curve method. Finally, the wind loads and structural responses are reconstructed based on the field‐measured accelerations during Typhoon Matsa. The accuracy of the identified results is verified by comparing the reconstructed acceleration responses with the field measurements. The results of this study show that the proposed inverse approach can provide accurate predictions of the wind loads and wind‐induced responses of super‐tall buildings based on limited measured responses.

The transmission tower-line system is widely used in electric infrastructures across the world and generally possesses a small stiffness and low structural damping. The excessive vibration of a transmission tower-line system subjected to seismic excitations may induce a structural damage or failure. To avoid the excessive vibration under strong earthquakes, a large transmission tower-line system requires some measures to abate their dynamic responses. Friction damper is a solution to realize the response control of a transmission tower-line system. In this regard, the response mitigation and performance assessment on a transmission tower-line system with friction dampers under strong earthquakes are actively carried out in this study. The analytical model of a transmission line is proposed based on Hamilton’s variational statement of dynamics and Lagrange’s formulation. A two-dimensional lumped mass model of a transmission tower is developed for the dynamic analysis by simplifying the three-dimensional finite element model. The mechanical model of a friction damper is established by considering the effect of damper axial stiffness. The equations of motion and dynamic analytical method of a transmission tower-line system without/with friction dampers subjected to seismic excitations are proposed. In addition, the approach for assessing energy responses of a transmission tower-line system without/with friction dampers subjected to seismic excitations is also developed. A real transmission tower-line system is taken as an example to examine the feasibility of the proposed control approach. The parametric study is conducted to investigate the effects of damper control force, damper stiffness, earthquake intensity, and damper location. The made observations demonstrate that the implementation of friction dampers in a transmission tower-line system can substantially suppress the seismic responses with optimal damper parameters.

Many engineering applications require the knowledge of wind loads on structures. However, it is difficult or even impossible to measure these excitation forces from prototype structures directly. In this paper, a Kalman filteringbased inverse approach is developed to estimate the wind loads on tall buildings. The inverse method allows estimating the wind forces on a tall building based on limited structural responses. The optimum solution of Kalman filter gain by solving the Riccati equation is used to update the wind load identification. The practicability and accuracy of the developed inverse method are evaluated based on wind tunnel testing results of a squareshaped tall building. The wind loads identified by the developed method are compared with those by an augmented Kalman filtering-based technique for further verification of the effectiveness and reliability of the presented inverse approach. The influences of key factors such as the type of wind-induced response, covariance matrix of external loads, covariance matrix of noise, errors of structural modal parameters, and levels of noise involved in the measured responses on the wind load estimations are examined and discussed. It is shown through the comparative studies that the developed inverse method is an effective tool for estimating the wind loads on tall buildings based on limited structural responses.

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