Bridge Engineering

Under the theme of wind resistance of the structures, the mechanisms of wind-induced vibrations of structures such as bridge decks and cables, and their countermeasures are investigated using wind tunnel tests and/or Computational Fluid Dynamics (CFD). Also, the research areas which cover both the wind engineering and structural engineering, such as the strong wind disaster prevention and the maintenance of structures considering airborne sea salt, are conducted.

Academic Staff

Tomomi YAGI

Tomomi YAGIProfessor (Graduate School of Engineering)

Research Topics

The major field of research is wind-induced instabilities of structures. Especially, the mechanism of wind-induced vibrations of bridges and the development of their countermeasures are investigated. Also, the mitigation of wind-induced disasters due to the typhoons and the tornados is another research topic.

Contacts

Room 452, Bldg. C1, Katsura Campus
TEL: +81-75-383-3165
FAX: +81-75-383-3168
E-mail: yagi.tomomi.7a@kyoto-u.ac.jp

Kyohei NOGUCHI

Kyohei NOGUCHIAssistant Professor (Graduate School of Engineering)

Research Topics

To realize more effective and efficient maintenance and management of bridges, I seek to predict the amount of airborne sea salt in each member of a bridge on the basis of a numerical simulation of air flows. Additionally, I also work on wind tunnel tests and computational fluid dynamics (CFD) to investigate and solve wind-induced vibrations of bridges.

Contacts

Room 453, Bldg. C1, Katsura Campus
TEL: +81-75-383-3435
FAX: +81-75-383-3168
E-mail: noguchi.kyohei.7z@kyoto-u.ac.jp

Research Topics

Bluff body aerodynamics

It is important to investigate the aerodynamics of fundamental cross sections such as circular and rectangular cylinders for the advance of researches in the aerodynamics of actual bridges. The interactions between the vortex shedding and the motion-induced forces are a very complex problem due to their unsteady properties, but they may have vital roles to control the critical wind velocity of various kinds of instabilities.

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Figure 1. Flow field around square cylinders

Wind-induced vibration of bridges

When a new bridge is desined and constructed, it is important to investigate aerodynamic stability of the cross section of the bridge in advance. For example, it is well known that the Tacoma Narrows Bridge (USA) collapsed in 1940 for a torsional vibration due to the action of wind. This research group conducts wind tunnel tests to investigate aerodynamic characteristics, vibration phenomena, and countermeasures to stabilize a bridge, by measuring wind force acting on the bridge and its response amplitude. Additionally, a bridge with a characteristic cross section, which has openings at the webs, is focused.

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Figure 2. Cross section with openings at the webs

Wind-induced vibration of cables

It is well known that the bridge cables vibrate under wind and rain, which is called the rain-wind induced vibration. The generation mechanisms of this complicated phenomenon are considered as water rivulet on the cable surface, axial flow in the wake and so on. Recently, the vibration under the dry condition, which is called the dry-state galloping, has also been noted. In this research group, the generation mechanisms of these instabilities, development of aerodynamically stable cables, precise response prediction are investigated.

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Figure 3. Rain-wind induced vibration

Evaluation of salt amount on bridge

Airborne salt particles, such as sea salt and anti-freezing salt, are transported by wind and adhere to each member of a bridge, which results in deterioration of steel and concrete members. Therefore, it is important to evaluate the amount of salt on each member of a bridge for effective maintenance. This research group seek to estimate the amount of salt adhering to bridge surfaces on the basis of a flow field around the cross section of a bridge. In addition, we also try to develop a method to decrease the salt amount by aerodynamic countermeasures.

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Figure 4. Air flow around cross section of bridge

Laboratory Website

http://brdgeng.gee.kyoto-u.ac.jp/