00:00Why are workers so determined to separate these steel wires one by one?
00:04Look closely. The tool in their hands is not ordinary equipment. It is like a giant steel
00:08comb. They are carefully straightening each strand, even though it takes much more time.
00:13At first glance, many people would think, wouldn't twisting all these steel wires together make them
00:17stronger? But the truth is exactly the opposite, because these messy-looking wires are not ordinary
00:22steel bars. They are pre-stressed steel strands, one of the most important parts inside a bridge.
00:26Later, each strand must pass through its own hole in this circular anchor.
00:30Then, hydraulic jacks pull each strand tight and lock it in place.
00:34Before the bridge carries any weight, they are used to put pressure on the concrete in advance.
00:38So engineers stretch these steel strands first, creating a built-in force that helps the concrete
00:43resist cracking. But if these strands are tangled together too early, problems appear. Some strands
00:48may already be carrying tension, while others may not actually be working. The entire system can
00:53become uneven and unstable. So what looks like workers simply organizing a pile of tangled wires
00:58is actually them preparing how the bridge will carry loads for decades, making sure every single
01:03steel strand does its job when thousands of vehicles pass over the bridge.
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