It looks like the center span was not supported by the vertical bridge supports. It makes one wonder what the engineers were thinking - even the construction people should have questioned it.
On the far pier, the diagonal braces are a meter above the water, while on the near pier they're 20cm below the water.
My bet is when it was constructed the two piers were at the same height, and the center span was supported on both ends - then the near pier sank, allowing the center span to slip off.
