Florida

FIU Bridge Collapse Raises Questions About Troubled Bridges

Take a peek under the 25 bridges in Miami-Dade and Broward counties that the state has rated "structurally deficient" and you might be taken aback by what you see.

Plywood or boards shore up concrete patches, rebar is exposed and there are plenty of cracks seen under the bridges that are given that lowest rating by bridge inspectors.

But none of that suggests the bridges will collapse any time soon, according to Miami-Dade County bridge engineering manager Dennis Fernandez.

"Structurally deficient means that the bridge, one of the elements of the bridge is in poor condition it does not mean the bridge is going to collapse," he said.

Of course, experts also said the FIU pedestrian bridge that collapsed on March 15, killing six, was safe.

But that was a uniquely designed, under construction bridge that included "fracture critical" members – meaning the failure of one such member could lead to collapse because it lacked redundant design elements. There are nearly 400 bridges in Florida that contain fracture critical members, according to FIU.

The failure of the FIU bridge occurred as a work crew was re-stressing one of two post-tension rods that ran through one of those fracture critical elements, a diagonal truss that joined with the deck on the northern end of the span. The work was ordered after cracks were found in the concrete near where the failure occurred.

When it comes to existing bridges, the most recent structural failure in South Florida came in October in Palm Beach County on a bridge that was not rated by inspectors as poorly as structurally deficient.

A section of concrete and railing fell from a bridge on U.S. 1 over the Earman River in North Palm Beach, leading to a shutdown of the span while it was re-inspected and repaired. It is now rated structurally deficient. Florida's Department of Transportation said corrosion in steel rods in the bridge had gone undetected.

The rating is assigned to bridges that have decks, superstructures, substructures or culverts and retaining walls in poor or worse condition, or have the worst ratings for structural conditions or waterway adequacy. It does not mean they are unsafe or in danger of collapse.

But they are supposed to be repaired or replaced within six years.

One of the bridges identified as structurally deficient – on Northeast 23rd Avenue over the Ibis waterway in Lighthouse Point – has been on the list for at least six years and has not been repaired or replaced sufficiently. The city’s public works department failed to return several calls seeking an explanation for its failure to adequately repair or replace the bridge.

Of the 25 bridges on the FDOT list in Miami-Dade and Broward, the busiest is on Oakland Park Boulevard in Lauderhill, over the C-13 canal. More than 53,000 vehicles a day cross the bridge.

It and another bridge on Stirling Road over the C-10 canal were added to the list in November. FDOT said in a statement it “prioritized the identified repairs of these bridges due to the design similarities to” the North Palm Beach bridge that suffered the partial structural failure in October.

In Miami-Dade, the busiest is on a section of the 79th Street Causeway entering North Bay Village, with about 23,000 vehicles a day.

In Miami-Dade, FDOT contracts with the engineering firm Louis Berger to inspect 362 bridges every two years, 18 of them fracture critical.

After the FIU bridge collapse, FDOT singled out Louis Berger as not being properly prequalified to do the design review work it was hired to do for that bridge’s design-engineering team.

But the firm is properly prequalified to oversee bridge inspections, FDOT said.

A Louis Berger spokeswoman declined to comment on its bridge work, citing litigation and investigations of the FIU bridge collapse.

Fernandez said he is satisfied with the safety of the bridges, even those rated structurally deficient.

“It only tells you, it’s a flag telling you have an element in poor condition and you need to correct it,” he said. “Once you correct the problem, the bridge will not be structurally deficient anymore.”

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