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A bridge from the past to the future

THE previous 900-ton steel bridge will weigh more than 1,000 tons as the result of its 10-month repair and restoration program. It was the most in-depth restoration effort since Waibaidu Bridge was built in 1907, the bridge's repairers said.

Restoring and reinforcing the original style had been the key concepts.

The main structure of Waibaidu Bridge is due to be shipped back to the Suzhou Creek today and tomorrow. Engineers will make use of favorable tides in lifting and setting the bridge back in its original location. Rivets

Almost 160,000 rivets hold China's first steel bridge together.

Once common practice in the construction industry, the use of rivets has been replaced by welding. Riveting, a dying art, is now only used on a small scale for building railway bridges and ships.

Bridge repairers Shanghai Shipyard found and recruited nearly 60 riveters from two factories in Shanhaiguan of Hebei Province and Xi'an of Shaanxi Province and flew them to Shanghai.

They worked in four-man groups, heating rivets to between 900 and 1,000 degrees Celsius before hammering them into the structure.

"At night, it was like watching a meteor flying across the sky as one worker cast a heated rivet high and the other quickly took it with tools and hammered it on the bridge without a second's delay,?a Shanghai Shipyard engineer said.

Up to 63,000 rusted or damaged rivets had to be replaced with exact copies of the originals, the project engineers said.Paint

Repainting was another major task and no effort was spared to ensure that all the rust and old paint was removed from the bridge before new coats were applied.

There was a thick layer of old paint on the bridge ?the result of many rounds of repainting during previous repairs.

After it had all been removed, workers used anti-rust paint of the same silver-grey color as before. Now, not only does the bridge look like new, but it has even more protection against rusting than before, according to the project engineers. Triangle-shaped Frames

Some triangle-shaped frames on the bridge's two arches have been replaced with curved ones to restore the original appearance.

During previous repairs, workers used the triangle structures to replace the old ones because they were easier to create than those with a curve, engineers said. Sidewalk

Wooden sidewalks will be restored on both sides of the bridge's vehicle lanes.

"The roadways are to be paved after the bridge is moved back to the creek. We will replace the previous concretes with wooden materials to build the new sidewalks to bring back the bridge's original and old style,?said Mao Anji, a project manager. Underwater

Compared to the bridge's main structure, its underwater section has been drastically altered.

Workers removed nearly 800 wooden pillars that were sunk 11 meters into the river bed. Now the bridge's three piers will be sitting on 36 1-meter-wide concrete supports that are deeply-rooted to a depth of 67 meters under the bottom of the creek, engineers said.


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