It's a common way to get structural steel members in whatever shape the design requires.

这是获得设计所需的任何形状的结构钢构件的常见方法。

During the inspection, they noted a major defect in one of the steel members below the bridge deck.

在检查过程中，他们注意到桥面下方的一根钢构件存在重大缺陷。

Fatigue is common on steel members that have been welded because welding has a tendency to introduce flaws in the material.

疲劳在焊接的钢构件上很常见，因为焊接容易在材料中引入缺陷。

With all that said, there's really only one reason that a steel member would crack like what's shown in the photos of the I-40 bridge.

话虽如此，钢构件会像 I-40 大桥照片中所示那样破裂，实际上只有一个原因。