• Wind and Structures
• /
• v.10 no.1
• /
• pp.1-22
• /
• 2007

The suppression of aerodynamic response of long-span suspension bridges during erection and after completion by using single TMD and multi TMD is presented in this paper. An advanced finite-element-based aerodynamic model that can be used to analyze both flutter instability and buffeting response in the time domain is also proposed. The frequency-dependent flutter derivatives are transferred into a time-dependent rational function, through which the coupling effects of three-dimensional aerodynamic motions under gusty winds can be accurately considered. The modal damping of a structure-TMD system is analyzed by the state-space approach. The numerical examples are performed on the Akashi Kaikyo Bridge with a main span of 1990 m. The bridge is idealized by a three-dimensional finite-element model consisting of 681 nodes. The results show that when the wind velocity is low, about 20 m/s, the multi TMD type 1 (the vertical and horizontal TMD with 1% mass ratio in each direction together with the torsional TMD with ratio of 1% mass moment of inertia) can significantly reduce the buffeting response in vertical, horizontal and torsional directions by 8.6-13%. When the wind velocity increases to 40 m/s, the control efficiency of a multi TMD in reducing the torsional buffeting response increases greatly to 28%. However, its control efficiency in the vertical and horizontal directions reduces. The results also indicate that the critical wind velocity for flutter instability during erection is significantly lower than that of the completed bridge. By pylon-to-midspan configuration, the minimum critical wind velocity of 57.70 m/s occurs at stage of 85% deck completion.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.2
• /
• pp.77-84
• /
• 2017

Recently, interest in safety has been increasing in every area, especially in the field of transportation. The accurate evaluation of the stability of road facilities is needed to improve the level of safety in the field of transportation and the application of new technologies is required to reduce the number of natural disasters. In this study, the wind data were compared and analyzed according to the type of measurement, and an evaluation of the stability of road signs using the wind data was conducted. In addition, a stability plan to secure road signs was elaborated and its effect on the wind load was analyzed. It was found that the wind data measured by a mobile atmospheric observing system (MAOS) was 2.43 times bigger than that measured by the Korea meteorological administration (KMA) and road weather information system (RWIS). In terms of their stability, the road signs were susceptible to failure caused by gusty winds and it was found necessary to ensure their stability. In the future, it will be possible to evaluate the stability of road facilities using road line weather data and the application of wind load reduction technologies is expected to improve road safety.