Giải đề IELTS Reading Passage 2 – The Bridge That Swayed

Bài đọc kể về cầu đi bộ Millennium Bridge ở London – cây cầu mới mở đã… lắc lư mạnh đến mức bị gọi là “wobbly bridge” và phải đóng cửa để nghiên cứu nguyên nhân. Đây là một passage rất “đời sống – kỹ thuật”, nhưng lại chứa nhiều từ vựng hay và dạng câu hỏi “khó nhằn” với nhiều bạn.

Trong bài này, OWL IELTS sẽ cùng bạn:

• Tóm tắt nhanh nội dung cả bài đọc
• Phân tích dạng câu hỏi và chiến thuật làm bài
• Cung cấp đáp án + giải thích ngắn gọn từng câu (14–26)
• Gợi ý từ vựng quan trọng cần nắm cho Reading & Writing

Giải đề IELTS Reading – Passage 2: The Bridge That Swayed

Nội dung chính

Bài đọc xoay quanh:

Sự cố cây cầu:

• Millennium Bridge (cầu đi bộ ở London) mở cửa năm 2000
• Khi đám đông đi qua, cầu lắc mạnh sang hai bên, khiến người đi phải bám lan can
• Báo chí đặt tên là “wobbly bridge” và cây cầu nhanh chóng bị đóng để điều tra

Quá trình tìm nguyên nhân:

• Ban đầu, kỹ sư nghi do gió + cờ phướn tạo lực lên cầu
• Sau đó, các thí nghiệm về cách con người đi trên sàn lắc chỉ ra rằng: Khi sàn lắc nhẹ, người đi bộ vô thức điều chỉnh bước chân và bước chân dần đồng bộ với nhịp lắc của cầu ⇒ làm dao động tăng lên
• Các trường đại học (Southampton, Imperial College) tham gia nghiên cứu
• Cuối cùng, người ta phải thiết kế giải pháp gia cường (tăng độ cứng hoặc tăng damping) để giảm dao động.

Dạng câu hỏi trong Passage 2

Trong đề Recent Actual Test Vol 3 Test 1, Passage 2 có:

• Questions 14–17: Choose FOUR letters A–I
  → Hỏi: Những điều gì đã xảy ra trong ngày cây cầu mở cửa?
• Questions 18–23: Summary Completion
  → Điền từ vào đoạn tóm tắt, giới hạn NO MORE THAN TWO WORDS.
• Questions 24–26: Table Completion
  → Điền tên đơn vị thực hiện test và vấn đề của từng bài test.

Chiến thuật làm Passage 2 theo từng dạng câu hỏi

Dạng “Choose FOUR letters” (Questions 14–17)

Đặc điểm:

• Câu hỏi: “Which FOUR of the following could be seen on the day when the bridge opened to the public?”
• Danh sách A–I cho nhiều chi tiết, chỉ 4 cái đúng.

Đối với dạng này, OWL khuyên các bạn nên tiếp cận theo từng bước sau đây:

1. Đọc qua list A–I trước: Gạch chân các từ như: moved vertically, swayed from side to side, band marched, hard to keep balance…
2. Xác định đoạn mô tả “ngày khai trương”: Tìm đoạn có chi tiết ngày 10 June 2000, đám đông, ban nhạc, mọi người phải bám lan can…
3. Đối chiếu từng lựa chọn với đoạn văn: Lưu ý paraphrase:
   • swayed from side to side ⇔ sway sideways
   • hard to keep balance ⇔ mọi người phải dừng đi, bám tay vịn để không ngã
4. Loại dần: Thứ gì không được nhắc, hoặc ngược hẳn với bài ⇒ cân nhắc và loại bỏ.

Dạng Summary Completion (Questions 18–23)

Đề cho sẵn một đoạn tóm tắt về quá trình nghiên cứu nguyên nhân cầu lắc. Bạn phải điền từ/ cụm từ y như trong bài, tối đa 2 từ.
Chiến thuật:

1. Xác định vị trí đoạn tóm tắt trong bài và xác định các keyword xung quanh các câu hỏi:
2. Với mỗi chỗ trống:
   • Đoán loại từ (danh từ, động từ, tính từ).
   • Tìm cụm trong bài có cùng nghĩa.
   • Lưu ý giới hạn “NO MORE THAN TWO WORDS”.

Dạng Table Completion (Questions 24–26)

Bảng tóm tắt các bài test và nhược điểm:

• Ai thực hiện?
• Vấn đề của bài test là gì?

Chiến thuật:

1. Gạch chân tên tổ chức / trường: Arup, University of Southampton, Imperial College.
2. Tìm đoạn mô tả từng test: “shake table”, “7.2m-long platform”…
3. Chú ý các cụm mô tả giới hạn / nhược điểm:

Giải đề IELTS Reading Passage 2: The Bridge That Swayed

You should spend about 20 minutes on Questions 14–26, which are based on Reading Passage 2 below.

THE BRIDGE THAT SWAYED

When the London Millennium footbridge was opened in June 2000, it swayed alarmingly. This generated huge public interest and the bridge became known as London’s “wobbly bridge.”

The Millennium Bridge is the first new bridge across the river Thames in London since Tower Bridge opened in 1894, and it is the first ever designed for pedestrians only. The bridge links the City of London near St Paul’s Cathedral with the Tate Modern art gallery on Bankside.

The bridge opened initially on Saturday 10th June 2000. For the opening ceremony, a crowd of over 1,000 people had assembled on the south half of the bridge with a band in front. When they started to walk across with the band playing, there was immediately an unexpectedly pronounced lateral movement of the bridge deck. “It was a fine day and the bridge was on the route of a major charity walk,” one of the pedestrians recounted what he saw that day. “At first, it was still. Then it began to sway sideways, just slightly. Then, almost from one moment to the next, when large groups of people were crossing, the wobble intensified. Everyone had to stop walking to retain balance and sometimes to hold onto the hand rails for support.” Immediately it was decided to limit the number of people on the bridge, and the bridge was dubbed the “wobbly” bridge by the media who declared it another high-profile British Millennium Project failure. In order to fully investigate and resolve the issue the decision was taken to close the bridge on 12th June 2000.

Arup, the leading member of the committee in charge of the construction of the bridge, decided to tackle the issue head on. They immediately undertook a fast-track research project to seek the cause and the cure. The embarrassed engineers found the videotape that day which showed the center span swaying about 3 inches sideways every second and the south span 2 inches every 1.25 seconds. Because there was a significant wind blowing on the opening days (force 3-4) and the bridge had been decorated with large flags, the engineers first thought that winds might be exerting excessive force on the many large flags and banners, but it was rapidly concluded that wind buffeting had not contributed significantly to vibration of the bridge. But after measurements were made in university laboratories of the effects of people walking on swaying platforms and after large-scale experiments with crowds of pedestrians were conducted on the bridge itself, a new understanding and a new theory were developed.

The unexpected motion was the result of a natural human reaction to small lateral movements. It is well known that soldiers are required to break step when crossing such a bridge. “If we walk on a swaying surface we tend to compensate and stabilise ourselves by spreading our legs further apart—but this increases the lateral push.” Pat Dallard, the engineer at Arup, says that you change the way you walk to match what the bridge is doing. It is an unconscious tendency for pedestrians to match their footsteps to the sway, thereby exacerbating it even more. “It’s rather like walking on a rolling ship deck—you move one way and then the other to compensate for the roll.” The way people walk doesn’t have to match exactly the natural frequency of the bridge as in resonance—the interaction is more subtle. As the bridge moves, people adjust the way they walk in their own manner. The problem is that when there are enough people on the bridge the total sideways push can overcome the bridge’s ability to absorb it. The movement becomes excessive and continues to increase until people begin to have difficulty in walking—they may even have to hold on to the rails.

Professor Fujino Yozo of Tokyo University, who studied the earth-resistant Toda Bridge in Japan, believes the horizontal forces caused by walking, running or jumping could also in turn cause excessive dynamic vibration in the lateral direction in the bridge. He explains that as the structure began moving, pedestrians adjusted their gait to the same lateral rhythm as the bridge; the adjusted footsteps magnified the motion—just like when four people all stand up in a small boat at the same time. As more pedestrians locked into the same rhythm, the increasing oscillation led to the dramatic swaying captured on film until people stopped walking altogether, because they could not even keep upright.

In order to design a method of reducing the movements, an immediate research program was launched by the bridge’s engineering designer Arup. It was decided that the force exerted by the pedestrians had to be quantified and related to the motion of the bridge. Although there are some descriptions of this phenomenon in existing literature, none of these actually quantifies the force. So there was no quantitative analytical way to design the bridge against this effect. The efforts to solve the problem quickly got supported by a number of universities and research organisations.

The tests at the University of Southampton involved a person walking on the spot on a small shake table. The tests at Imperial College involved persons walking along a specially built, 7.2m-long platform, which could be driven laterally at different frequencies and amplitudes. These tests have their own limitations. While the Imperial College test platform was too short that only seven or eight steps could be measured at one time, the “walking on the spot” test did not accurately replicate forward walking, although many footsteps could be observed using this method. Neither test could investigate any influence of other people in a crowd on the behaviour of the individual tested.

The results of the laboratory tests provided information which enabled the initial design of a retrofit to be progressed. However, unless the usage of the bridge was to be greatly restricted, only two generic options to improve its performance were considered feasible. The first was to increase the stiffness of the bridge to move all its lateral natural frequencies out of the range that could be excited by the lateral footfall forces, and the second was to increase the damping of the bridge to reduce the resonant response.

Questions 14–17

Choose FOUR letters, A–I.

Write the correct letters in boxes 14–17 on your answer sheet.

Which FOUR of the following could be seen on the day when the bridge opened to the public?

Questions 18–23

Complete the summary below.

Choose NO MORE THAN TWO WORDS from the passage for each answer.

Write your answers in boxes 18–23 on your answer sheet.

To understand why the Millennium Bridge swayed, engineers of Arup studied the videotape taken on the day of the opening ceremony. In the beginning they thought the forces of 18 ______ might have caused the movement because there were many flags and banners on the bridge that day. But quickly new understandings arose after series of tests were conducted on how people walk on 19 ______ floors. The tests showed people would place their legs 20 ______ to keep balance when the floor is shaking. Pat Dallard even believes pedestrians may unknowingly adjust their 21 ______ to match the sway of the bridge. Professor Fujino Yozo’s study found that the vibration of a bridge could be caused by the 22 ______ of people walking, running and jumping on it because the lateral rhythm of the sway could make pedestrians adjust their walk and reach the same step until it is impossible to stand 23 ______.

Questions 24–26

Complete the table below.

Choose NO MORE THAN THREE WORDS from the passage for each answer.

Write your answers in boxes 24–26 on your answer sheet.

Đáp án kèm giải thích – The Bridge That Swayed (Q14–26)

Questions 14–17 – Choose FOUR letters A–I

Đáp án và giải thích từng câu:

Questions 18–23 – Summary Completion (NO MORE THAN TWO WORDS)

Đáp án và giải thích từng câu:

Questions 24–26 – Table Completion (NO MORE THAN THREE WORDS)

Đáp án và giải thích từng câu:

Từ vựng quan trọng trong Passage 2 (The Bridge That Swayed)

• footbridge / pedestrian bridge: cầu đi bộ
• sway (v): lắc lư, đung đưa
• wobbly bridge: cây cầu lắc lư (biệt danh của Millennium Bridge)
• lateral movement: chuyển động ngang (sang hai bên)
• span (n): nhịp cầu
• handrails: tay vịn (trên cầu, cầu thang…)
• buffeting (by the wind): sự quật, tác động mạnh của gió
• suspension bridge: cầu treo
• swaying surface / platform: bề mặt / sàn bị lắc
• to compensate and stabilise: bù trừ và giữ ổn định (thăng bằng)
• spread one’s legs further apart: dang chân rộng hơn
• lateral push: lực đẩy theo phương ngang
• gait (n): dáng đi, kiểu bước chân
• dynamic vibration: dao động động lực (dao động do lực tác động)
• oscillation: sự dao động qua lại
• retrofit (n/v): gia cường / cải tạo thêm (thiết bị, kết cấu)
• stiffness: độ cứng (kết cấu)
• natural frequency: tần số riêng (tần số dao động tự nhiên)
• damping: độ giảm chấn, khả năng tiêu tán dao động
• resonant response: phản ứng cộng hưởng (dao động mạnh do trùng tần số)

Đây là các từ/cụm các bạn nên học để tốt được passage này, đồng thời tận dụng được cho IELTS Writing Task 1 (mô tả process, mechanics) hoặc Task 2 chủ đề engineering / infrastructure.

Tổng hợp bài giải đề IELTS Writing và Speaking được biên soạn bởi đội ngũ nhà Cú tại đây.