oldestguy said:
I assume the plan was to move up the canal and install the bridge section.
Agreed, that certainly had to be the intent.
The bridge is located in an urban area. Using crane(s) from the canal bank does not look like an option. Here is a satellite photo:
Other methods that could be reviewed may be:
1. Assembling the leaf in place. That was done decades ago, before very large cranes were common. Probably not cost effective now.
2. Build temporary trestle(s) adjacent to the bridge and use them to support crane(s). Again, being in an urban area limits space. Also, the waterway traffic likely has to be maintained.
3. Reinforce the adjoining bridge spans to support sizeable crane(s). Probably not cost effective.
This brings you back to barge mounted operations. I believe the Contractor was using a workable approach, he just did an unacceptable job of equipment selection and preparation. Each crane was on its own barge, the leaf was on a third barge. Failure appears to have happened when the cranes were lifting the leaf off its barge and standing it vertically on the same barge with the crane in the video background. If the leaf had been horizontal on a barge, it would be too big to maneuver into position. At some point the leaf would have to lifted to a near vertical orientation to be installed anyway.
Barge width is limited by bridge dimensions on the canal. More consideration of existing project site limitation may have allowed smaller modular leaf components to have been designed and assembled on site. Then smaller cranes could have been used - but that is hindsight.
This job, as fabricated, could have been accomplished in the way the Contractor planned. It would require much more attention to detail and careful execution.
![[r2d2] [r2d2] [r2d2]](/data/assets/smilies/r2d2.gif)