Those are the vehicles that wheel the bridge into place.
Doesn’t seem possible those temp supports were still in place.
Those shoring structures are the wheeled vehicles that carried the span to its final position. They were removed.. in hindsight, they should have supported the middle until they were able to install the suspension.
That was when they were moving it in place. Those were just bridge carriers and were removed after putting the bridge on top of the abutments. There wasn’t any support above or below the span at the time of collapse.
The orange/hydraulic supports were wheeled, motorized units used to lift, support, and position the span as it was fastened to the supports. They are in the roadway, and had to be removed, unfortunately, for traffic to flow. In other words, the span was only supported at its ends when it failed.
That's asking a lot of a span that is designed to be supported from above by cables. And, they expected it to stay that way for a while, because the center pylon that the cables would be hung from wasn't even built. Major screw up. Even if there was something to the idea of building on the ground and moving into place, the hanging cables should have been ready to attach. I wonder if the bridge span was designed under different assumptions, like it would be supported in the middle as it was put in place and the suspension cables were attached?