It's a bridge of steel framework.

那是座钢铁结构的桥梁。

youdao

This is a bridge with a steel framework.

这是一座钢结构的桥。

youdao

This bridge over the river has a steel framework.

这座跨江大桥是钢骨结构。

youdao

In Washington state this past week, a bridge collapsed when a truck driver's load bumped against the steel framework.

WSJ: Mo. highway buckles after rail cars hit overpass

Work has begun in Cardigan to remove the steel framework that has supported the castle walls for almost 40 years.

BBC: Cardigan Castle: Steel supports removal in ?11m work

In fact, Santiago seems like a smaller Buenos Aires, with a European style embodied in structures such as the Museo Nacional de Bellas Artes (National Museum of Fine Arts), housed within an elegant neoclassical building, and the Mercado Central (Central Market), with its filigreed steel framework imported from Britain.

FORBES: Lapostolle Residence, a Chilean Wine Country Hideaway