Early investigation of the florida bridge disaster that left six motorists dead has uncovered that the reason for the collapse was that they built the bridge in the wrong order. Rather than building the tower first, and then suspending the weight of the span with cables (cable stay design), they put the span in place first, and before they even began to build the tower to support it, it collapsed. How stupid can you be! Apparently very.
The difference is there was nothing holding up the bridge! It began to crack almost immediately and collapsed within 5 days. The design firm was lauded as a female eco friendly project, but it ended in disaster because they didn’t understand basic engineering.
In the cable-stayed bridge, the tower is the thing. It bears all of the load, which it transmits to the ground, and it is also the dramatic fulcrum of the design. Suitably enough, in boat-mad Florida, the tower in the UniversityCity design was supposed to evoke a sailboat.
Usually in cable-stayed bridges, the towers are built first, and deck slabs incrementally hooked up to the shortest cables. But at FIU, the reverse seems to have happened. Part of the prefabricated concrete deck went up first, and the tower had yet to be added when the collapse occurred. Of an unusual double-deck design, the section weighed 950 tons and was exceptionally large and heavy for a bridge intended to accommodate only pedestrians. It was swung into place on support pylons in a much-publicized operation employing a huge mobile jack. And there it sat for five days until it failed.
There is a rumor that in order to save money the tower was to be purely cosmetic and not bear any weight. Which would be the reason why the spans were so heavy. Apparently THAT DOESN’T WORK.
Two days before the collapse, as the New York Times reported, small cracks were observed at the slab’s north end, where the tower was to have been installed and where the failure appears to have occurred. The cracks caused sufficient disquiet that engineers were discussing the structural integrity of the span, proclaiming it safe only hours before the collapse.
Can you imagine what would have happened if a female tried to build the golden gate bridge!