“somethings” have reasons and meanings. That is what I want to know.
IF it works like other projects I’ve been on the tension is applied with a hydraulic jacking system. House movers used a system that ran jacks from one central location. Each jack still had to be manually operated. I’m not sure how the action would have been balanced on the post tension cables for the concrete bridge. Applying unequal tension on the cables would have skewed the load on the concrete. Any gauges used should have been calibrated. Whether that happened or not is not public. The source of the post tension cable is not known. Given the recent debacle over Japanese steel certifications, the cables may have been faulty. There are lots of factors that could have caused the bottom part of the concrete to be subject to a tensile load which would have led to quick failure. The forensic analysis will eventually provide the answers.