RESEARCHERS

To mark the year 2000, the Millennium Bridge was opened in London in June 2000. However, it was closed just after 3 days from the opening day due to the large lateral vibration by the pedestrians, and people in England had a fuss about this news. This was also released in Japanese TV, so you might have heard about it.

To solve this problem, Prof. Yozo Fujino, of the Bridge and Structure Laboratory at the Department of Civil Engineering, was hastily invited to an adviser to the project for controlling the vibration of the bridge at the request of the world-famous British consultant, Ove Arup. This time, he talked to us about it.

Profile of Prof. Fujino

In England, three millennium projects were conducted to commemorate the beginning of the 21st century. Those were the Millennium Dome, the British Airways London Eye, and the Millennium Bridge. The Millennium Dome was not so successful people because the exhibitions were not so attractive, and the British Airways London Eye had many mechanical troubles, so there were great expectations to the final project, the Millennium Bridge.

This bridge was opened in June 2000. The Queen Elizabeth cut the ribbon in the opening ceremony. It was very nice that many people came to cross this bridge, but the bridge girder vibrated laterally by the pedestrians, and the amplitude reached several centimeters. This was considered to be dangerous, so the bridge was closed 3 days after the opening day.

The Millennium Bridge was a much publicized bridge, designed by Norman Foster, one of the most well-known architects in the world. He won the competition. This was very light, slender, clear, sophisticated, and innovative bridge with the cables passed horizontally and the girders over them. However, the stiffness of the bridge, especially the lateral stiffness, was very low.

I heard from one of my friends that TV reported that the Millennium Bridge vibrated laterally and was closed. Usually I do not watch TV.

I remember it was around the middle of June, about 2 weeks after the Millennium Bridge was closed. When I was working in my office, the telephone rang. It was from Mr. Mike Willford, the manager of the technical development division, Ove Arup, England. Arup is one of the leading design consulting firms in the world, and did structural design of the Millennium Bridge. Mr. Willford seemed pressed for time and said, “The Millennium Bridge was closed due to the lateral vibrations by the pedestrians. I examined whether there had been similar phenomena or not, and found your paper in a journal. I heard that you were an adviser for the other case, the lateral vibrations of the footbridge in Paris which was opened in 1999. I would like to ask you to come to London, investigate the cause, and give us the advice for the elimination of vibrations.” We talked about an hour, and I decided to go to London.

This was how I became involved in the Millennium Bridge.

I went to London in early July, and inspected the bridge.

The bridge, over the River Thames at Downtown London, was more innovative than the impression I had seen from the picture, and I bet a lot of money had been spent to the bridge. At the same time, I was impressed that the bridge was elegant, but it was very dainty. The bridge was closed by necessity, and there were many instruments to measure the bridge performance.

Ove Arup made a special team to cope with this vibration problem. This consisted of Mr. Willford and several engineers for analysis group, design group, etc. I discussed with them, and they were really earnest. There were liability issues because the bridge was closed. The problem was whether this kind of phenomenon could be foreseen or not.

Actually, a similar vibration problem happened in Japan. A footbridge, when a lot of pedestrians crossed, vibrated laterally around 1990. Our laboratory made measurements and made a study about the cause of the vibration. We took the video of the bridge vibration and analyzed the movements of pedestrians on the bridge. Then, it was revealed that the way of walking of pedestrians changed according to the lateral vibration of the bridge, and this magnified the vibration of the bridge itself. I submitted a paper to an international journal in UK and it was published in 1993.

In London, we discussed the analysis and the prevention measure that we had conducted in the former Japanese case. It was very tiring since we had intensive discussions in English, but at the same time, it was very interesting and I learned a lot from the discussions.

I went to London again in September 2000. This time around, the purpose of my visit was mainly to discuss the methods for the vibration control. In Japan, vibrations of long-span bridges and tall buildings caused by winds or earthquakes always become issues, so Japan takes a lead position in the technique of the vibration control. Especially, Japan has an extensive experience in the active vibration control. I had been studying theoretical aspects of vibration control, while private companies are strong in making actual devices. So I visited London with an engineer of Ishikawajima-Harima Heavy Industries Co., Ltd., which was internationally well known at that field.

We proposed an innovative method using an active control scheme. I thought that this was very appropriate for the name “the Millennium Bridge”. However, they preferred conventional and proven methods, which was reasonable in a way. So, our proposal was eventually not accepted.

As explained, I had intensive and long discussions with the team in London. It included an executive director as well as a young female engineer. The impressive thing was that they talked equally at the technical discussions regardless of their positions and age. The fact that young people expressed their own views and ideas freely impressed me a lot.

All of them are graduates from Cambridge or Ecole Polytechnique in France, and seemed very brilliant. However, I felt that Japan was more advanced in the field of bridge technology and that Japanese engineers could compete with them.

What I felt was that the social climate was different in Japan. There are many good points in Japan, but there are also some weak points when Japanese engineers work internationally. For example, Japanese people take into consideration the hierarchical relation of age even at the technical meetings. Also, they are not familiar to discussions. I felt a lot of things.

The foreign language ability is also important. I don’t know whether it is good or bad, but English is becoming the universal language today. Even in Asia or Africa, international meetings are conducted in English. I studied at a graduate school in Canada, so I can use English to certain level.

I strongly recommend young students to arrange an opportunity to study abroad.

To become a world-class engineer, one has to learn various abilities. I think that communication skills including technical capabilities and languages are particularly essential.

Of course, technology is different from country to country, and place to place, but the fundamental technology is common. Establishing firm foundations, acquiring competitive techniques and skills, and transiting them to the world through technical papers/articles or engineering products, you will have a good chance. As I said before, if I had not written that paper in English, I would not have been invited to be an adviser on the Millennium Bridge.

Talking about bridges, many long-span bridges have been constructed in Japan. From now on, the number of construction of long-span bridges will drastically decrease. Let’s make use of the technologies that we have developed in the past, for international applications. This will become more and more important.

To acquire technical capabilities and communication skills, and transmit the research achievements to the world, we can get the opportunities to be involed in the exciting projects in the world.

If you need more information about us, visit http://www.bridge.t.u-tokyo.ac.jp/