Rating:
3 votes

FIU-Sweetwater University City Bridge (collapsed)

Photo 

A rendering of what the bridge will look like upon completion

Florida International University News Bureau

View this photo at news.fiu.edu

BH Photo #419445

Map 

Video 

Dashcam of collapse

Play video

Description 

Concrete truss with faux cable stays pedestrian bridge over busy Tamiami Trail (US 41) was to have connected the Florida International University main campus to the Sweetwater community to the north.

The bridge was under construction, with the south span over US 41 having been prefabricated offsite via "Accelerated Bridge Construction" techniques, and was then moved into place as a whole unit on Saturday March 10, 2018. The north span over Tamiami Canal had not yet been built.

On March 13, an engineer noticed cracks, and at 9:30 AM EDT on March 15 "cracking whip" noises were heard from it. At 1:30 PM, while post-tensioning rods were being tightened, it suddenly collapsed onto cars below on US 41 that were stopped at a red light. Several videos exist of the actual collapse. There were 6 fatalities, including 1 construction worker, and 9 injuries. Multiple investigations are ongoing, including the NTSB, and lawsuits have been filed.

For more information, see national news media, and the wikipedia link below.

Facts 

Overview
Lost concrete truss bridge over US 41 and Tamiami Canal on pedestrian walkway
Location
University Park, Miami-Dade County, Florida
Status
Collapsed while under construction
History
Collapsed suddenly during construction March 15, 2018
Builders
- FIGG Engineering Group of Tallahassee, Florida
- Florida International University
- Munilla Construction Management (MCM)
Design
Concrete truss with post-tensioned members and faux cable stays. Single truss web at center of bridge deck. Each panel shaped differently to match cable stays. Roof/upper chord also would protect pedestrians on the bridge from the elements, hence listed as "Covered".
Dimensions
Length of largest span: 174.0 ft.
Total length: 320.0 ft.
Deck width: 30.0 ft.
Approximate latitude, longitude
+25.76132, -80.37279   (decimal degrees)
25°45'41" N, 80°22'22" W   (degrees°minutes'seconds")
Approximate UTM coordinates
17/562896/2849401 (zone/easting/northing)
Inventory number
BH 80754 (Bridgehunter.com ID)

Update Log 

  • April 25, 2018: Updated by Roger Deschner: Changed bridge type from cable stayed to concrete truss with faux cable stays
  • March 19, 2018: New video from Clark Vance
  • March 17, 2018: Added by Roger Deschner

Related Bridges 

Sources 

Comments 

FIU-Sweetwater University City Bridge (collapsed)
Posted April 25, 2018, by Amanda

Regarding the Drew Bridge:

Unfortunetly the Drew Bridge collapsed under heavy floodwaters about 2 weeks ago.

The swing pier was destroyed, although I gather that the truss superstructure, despite severely damaged, was not a complete loss and has been relocated, fenced off next to the Hal W. Adams Bridge.

FIU-Sweetwater University City Bridge (collapsed)
Posted April 25, 2018, by Roger Deschner (rogerdeschner [at] gmail [dot] com)

So, now that this incident is down to lawsuits and NTSB investigations, what next? There is clearly a need for a bridge at this location. FIU students are being killed crossing busy US 41.

I assume they will not simply try again to build this failed design. That would be a travesty, and a dishonor to the 6 who lost their lives here.

I do like Nathan Holth's idea of moving and rehabilitating the remains of the historic Drew Bridge. It might actually fit into this space with its big center pier, which could be located between the road and the canal. Or there may be another historic bridge available for reuse, such as Indiana's 9-span Bridge. Such an historic bridge could be an interesting classroom for FIU engineering students.

Or simply build a more conventional steel through truss bridge. The requirements of the site dictate a through truss, those being clearance requirements above the road, along with a desire to minimize how many stairs pedestrians would have to climb. This part of the original design was correct - it was to have been a through truss to meet these basic requirements. However, successful concrete truss bridges are rare, perhaps for a reason.

If no available historic bridge can be found, build a new steel through truss, but build it deliberately to be a classroom, with ready connectors and power outlets for stress monitors and other instrumentation, so the engineering students could learn how to use these tools on a real bridge. Make the deck to be inside the truss webs, so that the bottom chord is easily visible. (Example: rehabbed Chatham Street Bridge in Blue Island IL.) If they would like to make it a bit fancier than a simple Warren truss, it could be a Baltimore, Pennsylvania, or Lattice truss with their interesting geometry. Those are designs intended to carry heavy trains, which could minimize sway from people walking across. A conventional steel truss bridge would be easy and safe to build using "accelerated bridge construction" techniques. Such a replacement bridge could be both a memorial to the 6 fatalities, and a classroom for the future bridge builders at FIU.

A bridge is clearly needed here. The lawsuits and NTSB investigations are "water under the bridge". It's time to start thinking about the new bridge.

FIU-Sweetwater University City Bridge (collapsed)
Posted March 31, 2018, by James Baughn (webmaster [at] bridgehunter [dot] com)

Latest updates about the bridge collapse (in short, we still don't know much):

http://www.miamiherald.com/news/local/community/miami-dade/w...

FIU-Sweetwater University City Bridge (collapsed)
Posted March 19, 2018, by Nathan Holth (webmaster [at] historicbridges [dot] org)

As near as I can tell the cables were supplemental intended to reduce oscillations from pedestrian usage. I was hoping to find a definitive answer of "what type of bridge was this" but its not clear. It might be loosely called an "extradosed concrete truss bridge" but I am not sure if that is appropriate, although extradosed bridges rely less on the cables for support than a full-blown cable-stayed bridge. The spans were definitely concrete trusses, and were definitely supposed to be self-supporting after moved into position over the roadway before the tower cables were installed. I selected some sheets from the Design/Build proposal that has renderings and prelim drawings (including showing the erection sequence) and attached them here. Currently a lot of the project documentation can be found here: http://facilities.fiu.edu/projects/BT-904.htm

Attachment #1 (application/pdf; 12,614,818 bytes)

FIU-Sweetwater University City Bridge (collapsed)
Posted March 17, 2018, by Roger Deschner (rogerdeschner [at] gmail [dot] com)

I am at a bit of a loss to categorize this bridge type from the artist's rendering of the completed bridge. (Regardless of its collapse.) I think it may be primarily a truss bridge, with the cable stays there only for reinforcement in case of a Category 5 hurricane, which it had been designed to withstand. If so, what kind of truss is it? I guessed "Warren with all verticals" but I could be wrong on that. It's kind of half of a Pratt. Each panel is different.