雅思阅读真题+题目+答案：The Diagnose of Bridge

雅思阅读真题+题目+答案：The Diagnose of Bridge

A

MOST road and rail bridges are only inspected visually, if at all. Every few months, engineers have to clamber over the structure in an attempt to find problems before the bridge shows obvious signs of damage. Technologies developed at Los Alamos National Laboratory, New Mexico, and Texas A&M University may replace these surveys with microwave sensors that constantly monitor the condition of bridges.

B

“The device uses microwaves to measure the distance between the sensor and the bridge, much like radar does,” says Albert Migliori, a Los Alamos physicist. “Any load on the bridge – such as traffic – induces displacements, which change that distance as the bridge moves up and down.” By monitoring these movements over several minutes, the researchers can find out how the bridge resonates. Changes in its behavior can give an early warning of damage.

C

The Interstate 40 bridge over the Rio Grande river in Albuquerque provided the researchers with a rare opportunity to test their ideas. Chuck Farrar, an engineer at Los Alamos, explains: “The New Mexico authorities decided to raze this bridge and replace it. We were able to mount instruments on it, test it under various load conditions and even inflict damage just before it was demolished.”丨n the 1960s and 1970s, 2500 similar bridges were built in the US. They have two steel girders supporting the load in each section. Highway experts know that this design is “fracture critical” because a failure in either girder would cause the bridge to fail.

D

After setting up the microwave dish on the ground below the bridge, the Los Alamos team installed conventional accelerometer at several points along the span to measure its motion. They then tested the bridge while traffic roared across it and while subjecting it to pounding from a “shaker,”，which delivered precise punches to a specific point on the road.

E

“We then created damage that we hoped would simulate fatigue cracks that can occur in steel girders,” says Farrar. They first cut a slot about 60 centimeters long in the middle of one girder. They then extended the cut until it reached the bottom of the girder and finally they cut across the flange – the bottom of the girder’s “I” shape.

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雅思阅读真题题目：

Questions 1-4

The reading Passage has seven paragraphs A-l.

Which paragraph contains the following information?

Write the correct letter A-l, in boxes 1-5 on your answer sheet.

1 The professional team put pressure to test the motion of the bridge.

2 Engineers apply knife to the bridge to excite cracks.

3 A precious chance of experiment to certificate ideas.

4 The popular application of the microwave inspection system within a decade

5 How the microwave works

Questions 6-9

Choose the correct letter, A, B, C or D.

Write your answers in boxes 6-9 on your answer sheet.

6 What is the responsibility of engineers in order to prevent the damage of the bridge before the invention of the microwave sensors?

A They have to climb over the bridge.

B They have to regularly check the bridge

C They have to inspect the condition of the bridge through monitors.

D They have to employ others to help them check the bridge.

7 What did the device take advantage of the microwaves to do?

A to calculate the distance

B to induce displacements

C to change the distance

D to give an advanced warning

8 Why did highway experts think the design as “fracture critical” ?

A Engineers failed to take several tests according to different conditions.

B Engineers failed to install conventional accelerometers.

C The supporting part would probably make the bridge fall down.

D No cars drove past the bridge.

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