Sorry for the delay.
So, you're proceeding across the bridge in the order: Eanos, Pendrake, Semabin.
The bridge consists of spans of massive stone blocks. The bridge seems solid. It rises 2 feet above the water surface at its highest point, eventually connecting to the road on the other side which soon comes into view in the distance. The stonework is about a mile long across this massive underground sea, but at the other side an expanse of pale light comes through the Underdark, enabling you to see a city.
About a third of the way across the bridge a few of the massive stone blocks are cracked and askew. A navigable path still exists where the corners of the crooked stones come close enough together, but unlike the minor erosion endured by the majority of the bridge, this section seems to have sustained damage.