Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Florida bridge evidence was 'melted down' after collapse

3112525 floridabridgecollapsepa355540903to2

Materials from the site of the collapsed Florida bridge were destroyed in the aftermath of the tragedy which killed six people, it has been revealed.

A Miami circuit judge has demanded answers to why 26 threaded steel rods were melted down after being removed from the site by one of the companies working on the FIU pedestrian bridge.

The contractor Structural Group has admitted destroying the rods, despite them previously being “identified for preservation” along with a steel bolt.

However a lawyer for the group said that it was acting under the instructions of general contractor MCM’s site supervisor

“It’s distressing,” said Judge Jennifer Bailey. “I’m dismayed, as I’m sure everyone in this room is dismayed, at this turn of events – given the time and effort and detail that was put into the order regarding the disposition of the material from the bridge collapse.”

“I just want to know what happened and who was on the scene and who were the decision makers and how did this happen?”

A photograph of shows that only the bolt – laying on top of the rods – had a yellow tag attached to it.

The rods are the same size as those being tightened in the truss that failed, so they could be significant, one lawyer argued. The NTSB also collected rods of that size from the site and tested them, finding no issues with the materials, the agency said. 

Last month, the NTSB released shocking photos of cracks found on the bridge

Like what you’ve read? To receive New Civil Engineer’s daily and weekly newsletters click here.

Readers' comments (1)

  • The failure would seem likely to me to have propogated at the bottom end of the end diagonal compression member. From the photos of pre-collapse cracking, the diagonal appears to be "punching" through the deck end, partially held by the end vertical member. The loss of prestress in the diagonal, which was being restressed when collapse occurred, seems to indicate that the diagonal is beginning to punch through the deck and be damaged. The "punching" behaviour would be exacerbated by the design whereby there is only a single central arrangement of web members transmitting forces to a wide slab, such that "shear lag" is significant. The prestressing of the deck was distributed over its full width and would be less able to combat the localised compression from the diagonal at the bridge end.

    Thus I tend to suspect a design flaw. The prestressing of an end compression diagonal was presumably merely to overcome the temporary condition during erection when the bridge was being supported by SPMT's inboard from the ends. The restressing being attempted when the bridge was later supported at its ends was probably the "straw that broke the camel's back" . The design had been further compromised by the unusually shallow inclination of the diagonal to match the "dummy" cable staying of the bridge. There is surely a lesson here in "imitation acchitectural concepts", whereas in my view bridges should be about honest structural form.
    Alan Hayward FREng CEng FICE FIStructE

    Unsuitable or offensive? Report this comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.