Questions about the materials used during the construction and whether the projects were properly engineered have been the subject of national debate ever since a high-speed train plowed into the back of a stopped train on the same track on July 23 last year in the eastern city of Wenzhou. The crash killed 40 people and injured 191; a subsequent investigation blamed in particular flaws in the design of the signaling equipment.

Photographs on Chinese Web sites on Friday appeared to show that the collapsed section of the Yangmingtan Bridge’s ramp had fallen on land, not in the river.

According to the official Xinhua news agency, the Yangmingtan Bridge was the sixth major bridge in China to collapse since July 2011. Chinese officials have tended to blame overloaded trucks for the collapses, and did so again on Friday.