Fiu Bridge Collapse Engtips
Update on FIU Pedestrian Bridge Collapse The FIU pedestrian bridge, which was under construction when it collapsed, was being built as a means for students to cross over a busy six-lane roadway. FIU Bridge Collapse One Year Later: Much Loss and Few Answers The disaster is a construction failure born of design errors and what appears to be a misguided attempt to address them by adding. At the time of collapse, the post-tensioning bars were being re-tensioned at the specific instructions of the EOR. The bridge had structural design deficiencies that contributed to the collapse during construction stage III. The cracks on the bridge occurred due to deficient structural design.
On March 15, 2018, a 175-foot-long (53 m), recently-made section of the collapsed onto the , resulting in six deaths, eight injuries, and eight vehicles being crushed underneath.The initial construction on the pedestrian bridge was located in front of the campus of FIU in, a suburb west of, and was in the process of post-tension rod adjustment when it suddenly failed. The road beneath it had been opened to traffic.An examination carried out by the discovered faults in the design of the bridge, which overestimated the strength of the bridge in the region which failed, and underestimated the load it would be expected to carry. Contents.Background The FIU Sweetwater UniversityCity pedestrian Bridge, located just west of the intersection of (Southwest 8th Street) and Southwest 109th Avenue, was planned to connect the FIU campus to student housing neighborhoods in.
It was intended to improve pedestrian safety, as the busy crosswalks at this wide, busy intersection had been identified as a safety hazard and the site of fatal collisions. The $14.2 million project was funded with a $19.4 million (TIGER) grant from the in 2013, along with state agencies. The bridge itself cost $9 million to construct.The main companies behind the construction project are Munilla Construction Management (MCM), a Miami-based construction management firm, and FIGG Bridge Engineers, a -based firm.
Unlike most bridges in Florida, the design for this project was overseen by the university itself, not the.Florida International University is known for its expertise in accelerated bridge construction, and has attracted international scholars as PhD students. It is home to the federally-funded Accelerated Bridge Construction University Transportation Center, which sponsors industry conferences and seminars. Bridge layout. Elevation Engineering Drawing of Proposed FIU Sweetwater Pedestrian BridgeThe full 320-foot-long (98 m) pedestrian bridge was to cross both a major roadway and a parallel water canal with two separate spans connected at a faux cable-stay tower. The main roadway-crossing span was 175 ft long, the shorter canal span was to be 99 ft long.
An elevator and stairs at the south end added 31 ft, and at the north end, 15 feet, for a total bridge length of 320 feet. At the bridge site, the Tamiami Trail roadway has seven lanes of traffic plus one turn lane. The main span was rolled into place and set on support columns on March 10, five days before the collapse. The canal span, access ramps, and faux cable-stay tower had not yet been built. Pedestrian use was to begin when the whole project was complete.
The school was on at the time of collapse. The section of the bridge that collapsed weighed 950 short tons (860 metric tons) and fell onto several vehicles on the roadway below.Bridge construction and design Construction of the bridge began in March 2016 and was scheduled to be completed in December 2018. The bridge's main span was assembled adjacent to the highway using (ABC), a technique promoted at the university. It was lifted into place on the morning of March 10, five days before the collapse, during a weekend closure of the highway. University Park (the United States) Show map of the United StatesThe new pedestrian bridge was designed to connect the campus to student housing in a dramatic sculptural way, and also to showcase the school's leadership in the ABC method of rapid bridge construction.The bridge was a structure.
Concrete structures are generally 10 times heavier than equivalent steel designs. The bridge was made using a new formulation for concrete intended to stay cleaner than standard concrete formulations. In the main bridge span, the concrete floor deck, roof, and diagonal struts each contained post-tensioning cables whose compressive effect on the concrete could be adjusted after the concrete was cured. Adjustments were expected each time the span was moved onto a different foundation with different support points.The full bridge project was styled to look like a, with a pylon tower and high cables for dramatic effect. But functionally and structurally it was actually a, with the spans being fully self-supporting.
The bridge spans used a novel concrete truss design invented for this project, a 're-invented concept'. Concrete truss bridges are rarely constructed, and few exist. Schematic of the bridge.
Green: collapsed parts, Blue: not installed at the time of the collapse. The diagonal beam that was undergoing post-tension cable/rod adjustment at the time of the collapse is highlighted in red. Reports of cracking Two days before the collapse, on March 13, the third day after lifting of the main span, the project's lead engineer discovered cracks at the north end of the span (the end that later broke). He reported this by voicemail to a (FDOT) employee.
He thought this was not an immediate safety issue, merely something that would need to be repaired later. The FDOT recipient was away for several days and did not hear this message until the day after the collapse.At 9 a.m. On March 15, a university employee heard a loud 'whip cracking' sound while under the bridge span, waiting for a red traffic light. At the same time, the design-build team met for about two hours at the construction site to discuss the cracks discovered on March 13. Representatives from both FIU and the FDOT were present. The FIGG lead engineer's conclusions were that the structural integrity of the bridge was not compromised and that there were no safety concerns raised by the presence of the crack.
FIGG also insisted that no crack repairs should be carried out until the stabilizing of the node and pylon diaphragm with post-tensioning was completed.The mayor of Miami-Dade County, said that workers conducted a stress test on the morning of March 15. Collapse At 1:47 p.m.
On March 15, the north end of the installed bridge span sagged deeply as the first diagonal fractured, folded, and immediately dropped the heavy full span onto the roadway below. A surveillance video shows the collapse sequence took only a few video frames.United States Senator and FIU adjunct professor that engineers were tightening loosened cables on March 15: Workers were adding more tension to the steel rod inside a concrete diagonal strut at the north end. The, who are investigating the collapse, stated that crews were applying 'post-tensioning force' on the bridge before the collapse.
The tensioning rod that was being tightened at the time of the collapse, with a hydraulic tensioning machine (blue) still attached to its end, extends from the canopy in the upper left of this image.As the post-tensioning operation by the VSL company was being carried out on bridge diagonal member support #11, the bottom joint (which contains the anchor nut for the post-tensioning rod) apparently failed explosively, causing the bridge to collapse. Currently, it remains unknown why the joint may have failed, although post-tensioning remains a likely contributor.The span that collapsed weighed 950 short tons (861 ). Deaths The event killed six people: one construction worker and five people sitting in cars at a stoplight below.At the time of the collapse, the roadway was open and multiple cars were stopped at a traffic light under the span.
A driver who survived the collapse reported that small rocks fell onto her car just before the front of her car was crushed. A worker saved himself when he heard cracking and locked his safety harness just before the collapse. Eight cars were crushed. Six people were killed and eight others were injured. Five of the victims were killed immediately when the bridge fell; one died at the hospital. An employee of VSL, Navaro Brown, 37, worked for the company contracted to apply post-tensioning and died in the collapse.
Two other employees of the company were hospitalized. The other deceased victims of the tragedy were Alberto Arias, 53, Brandon Brownfield, 39, FIU student Alexa Duran, 18, Rolando Fraga, 60, and Oswaldo Gonzalez, 57. Subsequent events Southwest 8th Street between Southwest 107th and 117th Avenues was closed until March 24 while the debris was cleared.A team of 15 people from the National Transportation Safety Board (NTSB) began their investigation on the morning of March 16. On March 19, 2018 the first civil lawsuit was filed against Figg Bridge Engineers, MCM, Bolton Perez & Associates, the project's consulting engineer, Louis Berger, and Network Engineering Services for reckless negligence. Members of the NTSB's Go Team for the investigation boarding an FAA plane to travel to Miami.On March 15, 2018 the National Transportation Safety Board (NTSB) launched a to investigate the bridge collapse.
The accident number assigned is HWY18MH009. On March 16, 2018 the NTSB Investigators held their first press conference to discuss the inquiry into the bridge collapse. Noteworthy points from the meeting included a statement that the inquiry was in the very early stages, that cracks in the bridge superstructure did not necessarily make the bridge unsafe, that on-site investigations would take about a week, that preserving perishable evidence was crucial, and that bridge workers were applying a 'post-tensioning force' on the bridge before the failure. Also on March 16, 2018 the FDOT released a letter to the public with information about the bridge collapse:According to standard procedures, FDOT issued a permit at the request of FIU's design build team to close SW 8th Street during the installation of the FIU pedestrian bridge on Saturday, March 10. While FDOT has issued, following a request from the FIU design build team, a blanket permit allowing for two-lane closures effective from January through April, at no time, from installation until the collapse of the bridge, did FDOT receive a request to close the entire road. The department was also not made aware by the FIU design build team of any scheduled 'stress testing' of the bridge following installation and has no knowledge or confirmation from FIU's design build team of 'stress testing' occurring since installation. Per standard safety procedure, FDOT would issue a permit for partial or full road closure if deemed necessary and requested by the FIU design build team or FIU contracted construction inspector for structural testing.Additional, in the interest of full transparency, FDOT is today releasing the transcript of a voicemail left on a landline on Tuesday, March 13, by W.
Denney Pate, FIGG's lead engineer responsible for the FIU pedestrian bridge project. The transcription is below.:'Hey Tom, this is Denney Pate with FIGG bridge engineers. Calling to, uh, share with you some information about the FIU pedestrian bridge and some cracking that's been observed on the north end of the span, the pylon end of that span we moved this weekend. Um, so, uh, we've taken a look at it and, uh, obviously some repairs or whatever will have to be done but from a safety perspective we don't see that there's any issue there so we're not concerned about it from that perspective although obviously the cracking is not good and something's going to have to be, ya know, done to repair that. At any rate, I wanted to chat with you about that because I suspect at some point that's gonna get to your desk.
So, uh, at any rate, call me back when you can. This voicemail was left on a landline and not heard by an FDOT employee until Friday, March 16 as the employee was out of the office on assignment.On Wednesday, March 14, Alfredo Reyna, the Assistant LAP Coordinator and an FDOT consultant, received a phone call from Rafeal Urdaneta, a Bolton Perez & Associates employee, notifying him of a midday meeting scheduled for Thursday, March 15 with W. Denney Pate and other members of the FIU design build team that are responsible for the project. FDOT is routinely included in meetings during LAP project construction. Reyna attended the meeting which occurred shortly before the bridge failure and collapse and was not notified of any life-safety issues, need for additional road closures or requests for any other assistance from FDOT.The responsibility to identify and address life-safety issues and properly communicate them is the sole responsibility of the FIU design build team.
At no point during any of the communications above did FIGG or any member of the FIU design build team ever communicate a life-safety issue. Again, FIGG and the FIU design build team never alerted FDOT of any life-safety issue regarding the FIU pedestrian bridge prior to collapse. (bold in original)The tragic failure and collapse of the pedestrian bridge at FIU is the subject of an active and ongoing investigation led by the National Transportation Safety Board (NTSB) as well as local and state law enforcement investigations. As FDOT assists in these investigations, we will continue our internal review and release all pertinent information as quickly as possible while ensuring its accuracy.On March 21, 2018 the NTSB sent out a press release detailing the items from the collapse that required further examination at the Turner Fairbank Highway Research Center, in McLean, Virginia.
They also confirmed workers were adjusting rod tension when the collapse occurred.On May 23, 2018 the NTSB released a preliminary report titled 'Highway: Collapse of Pedestrian Bridge Under Construction Miami, Florida (HWY18MH009)' which summarized the accident. They said they are evaluating the emergence of cracks in the region of diagonal members 2 (south end of the bridge) and 11 (north end of bridge), and the propagation of cracks in the region of diagonal member 11. Pictures of the cracks from February 24 (before the walkway had been moved into place) were also given.Consulting engineers, Bolton-Perez and Associates, had taken several pictures of severe cracks in diagonal member 11 and adjacent to vertical member 12 which had appeared when the bridge was moved into place on March 10.The Turner-Fairbanks Highway Research Center, at the request of the NTSB, tested samples of steel and concrete from the collapsed bridge, and found that they met the project requirements.
The NTSB similarly asked the Federal Highway Administration (FHWA) to examine the design of the bridge. The FHWA examination discovered that the bridge designers had overestimated the strength of one section of the bridge - at the point where the diagonal member 11 and vertical member 12 met the bridge deck - and underestimated the load that that same section would carry.In June 2019, OSHA released its final report on the FIU bridge collapse and concluded FIGG bridge engineers failed to recognize collapse was imminent when they inspected the bridge hours earlier. They also concluded the bridge had structural design deficiencies, severe cracks were wrongly ignored by the Engineer of Record and warranted street closure, and contract bridge design experts violated basic FDOT construction requirements.Legal action On March 21, 2018 U.S. Transportation Secretary Elaine Chao asked the department's inspector general to probe whether a federally funded UniversityCity pedestrian bridge complied with all rules. A subsequent internal memorandum from the Inspector General of the U.S. ^ Shapiro, Emily; Doom, Justin (March 16, 2018).
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Fiu Bridge Collapse Eng-tips
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Fiu Bridge Collapse Engtips Center
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Figg Engineering Bridge Collapse
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The people of Sweetwater, Florida were supposed to wait until early 2019 for the Florida International University-Sweetwater University City Bridge to open. Instead, they will wait about that long for an official assessment from the National Transportation Safety Board of why it collapsed just five days after its installation, killing at least six people.Early Thursday afternoon, the 174-foot, 950-ton span of the pedestrian bridge crashed onto the eight-lane road below, crushing several cars. As of Friday afternoon, recovery operations were ongoing.In the immediate aftermath of the disaster, many queries have centered on the unconventional technique used to build the bridge, something called Accelerated Bridge Construction, or ABC. But ABC is more complicated than its acronym suggests—and it’s hardly brand new.Engineers and construction workers have used similar techniques in Europe for decades, and in the US since the mid-2000s. It has been used hundreds of times, in nearly every state. A notes over 800 federally-funded bridges were built or repaired with the technique between 2010 and June 2012 alone. ABC refers to dozens of construction methods, but at its core, it’s about drastically reducing on-site construction time.
Mostly, that relies on pre-fabricating things like concrete decks, abutments, walls, barriers, and concrete topped steel girders, and hauling them to the work site. There, cranes or specialized vehicles known as Self-Propelled Modular Transporter install them. A video posted online by Florida International University, which helped fund the bridge connects to its campus, showed an SPMT lifting and then lowering the span into place.
In a now-deleted press release, the university called the “largest pedestrian bridge moved via SPMT in US history,” but that doesn’t seem to mean much, engineering-wise. SPMTs have been around since the 1970s, and have moved much heavier loads. In 2017, workers used a 600-axle SPMT to salvage the 17,000 ton ferry that sank off the coast of South Korea in 2014.The ABC technique is much more expensive than building things in place, but cities and places like FIU like it for a specific reason: Because most of the work happens far away, traffic goes mostly unperturbed. When years- or months-long construction projects can have serious effects on businesses and homes, governments might make up the money in the long run. Workers installed this collapsed span in just a few hours.
These accelerated techniques are also much safer for workers, who do most their work well away from active roads. About 20,000 workers are injured in construction zone accidents each year; more than 600 die.In searching for a culprit for Thursday’s collapse, then, engineers say it’s wrong to point just to accelerated building construction, writ large. “Being a structural engineer, we all look to see, what broke, what was loose, what let go?” says Michael Culmo, a civil engineer with the Connecticut engineering firm CME Associates. (He was not involved in the Florida project.) “The real question is, what was happening at that moment that it went down? Was the contractor doing something on the bridge?
It was standing for five days, doing just fine. What happened on the fifth day?”The answers could run the gamut, from design flaws to fabrication flubs to installation issues. The Washington Post that an engineer called the state to report cracking two days before its collapse. Florida Senator Marco Rubio tweeted that the bridge’s cables had been loose, and workers had been tightening them when it collapsed. Local reports indicate workers were taking the structure through a stress test when it fell.
(FIU said the bridge was built to withstand a Category 5 hurricane.). “Usually, it’s more than one thing that causes a collapse,” says Culmo.Culmo notes the foot bridge’s design was unusual for a pedestrian connector. Ralph Verrastro, who works on ABC bridge construction with the Florida-based firm Bridging Solutions, agreed, that the bridge had been designed to be unusually heavy, using concrete trusses where others might use steel.The NTSB will remain in Florida to investigate the disaster for at least a week.
But infrastructure wonks warn this sort of tragedy shouldn’t scare Americans away from new bridges, or bridge repairs. The American Society of Civil Engineers reports are “structurally deficient,” meaning they’ve been limited to light vehicles, have been closed to traffic, or are in need of rehabilitation.
They still need help.Infrastructure Interestings.Meet the —and protect construction workers in the process.Why hosting the 2028 Olympics.to build the world’s first ship tunnel.