Subcontract Bridge

Readers may remember my post about the footbridge in Miami which collapsed onto a road full of cars during installation. A Twitter follower sends me an update, and the first thing I notice is this:

The plans for Florida International University’s pedestrian bridge included an innovative design approach by FIGG Bridge Engineers.

So the bridge was designed by FIGG; the original news reports said the engineering was carried out by Munilla Construction Management (MCM). This link provides some clarity:

FIGG Bridge Engineers, Inc. is the designer of the bridge, working for MCM.

Ah. In my original post I said:

A lot of companies have subcontracted out the actual work – designing, building, manufacturing, operating, maintaining – and instead busy themselves with “managing” the whole process. This involves lots of well-educated people in nice clothes sitting in glass-fronted office buildings sharing spreadsheets, reports, and PowerPoint presentations by email and holding lengthy meetings during which they convince one another of how essential they are.

In such an environment, it is inevitable that the quality of work suffers, errors go unnoticed, and – occasionally – catastrophes occur. Now I don’t know if that was the case at the Munilla Construction company, but somehow they’ve gone from an outfit who could deliver a project with their eyes closed to one that has just dropped a simple footbridge on eight lanes of highway. If I were investigating, I’d want to know who did the actual design and where it was done. I’d be willing to bet a hundred quid the calculations and finite element modelling were done outside the US to save money, or subcontracted to another company, and supervision – which involves expensive Americans – was at nowhere near the levels it should have been.

So I got the subcontracting part right. Were the calculations done outside the US? Well, FIGG is a US-based group but that doesn’t mean they don’t have a design office in Mexico employing number-crunching engineers on the cheap. But given the lead design engineer is called Denney Pate, I’ll give them the benefit of the doubt here. Back to the article:

Bolton Perez & Associates, the project’s construction engineering and inspection contractor

It is possible that the project’s prime contractor, MCM, and its post-tensioning subcontractor, in attempting to fix the problems, made an error that caused the bridge’s single truss to crack and give way.

So here are two more subcontracted bodies. Now it’s not unusual to bring in specialist inspectors and technical services, but it does add to the complexity of who’s in charge and where responsibility lies meaning the project management needs to be spot-on.

An official with FIU asked a representative with Bolton Perez their opinion of FIGG’s presentation analysis. Bolton, Perez said they could not comment at the moment, but would “expedite” a response in 2-3 days, according to the notes.

It’s telling that there is no mention of MCM in this exchange. What were they doing, then? Getting ready for Pride month? This is also illuminating:

Rice, the Georgia forensic engineer, remains most perplexed over the designer’s use of a single truss. “That just blew me away,” he says. “To have a single truss like that is violating one of the first tenants of structural engineering—provide redundancy. If you’re going to make a truss bridge, you have at least two trusses,” he argues.

Okay, so this is what FIGG say on their website:

Bridges designed by FIGG are purposeful works of art, functional sculptures within the landscape, that are created through a careful analysis of the site, contextual and environmental sensitivity, and a regional approach that encompasses a community’s particular needs, as well as the realities of funding and maintenance.

By capturing the powers of imagination, function, and technology, we build bridges that improve the nation’s infrastructure, while enhancing the appearance of communities across America and the quality of life for the people who live in them.

So they look nice but collapse during installation in a manner detrimental to the quality of life for those passing beneath them at the time.

There are two points to make here. Firstly, MCM seem to have been adding little value; the fact their name doesn’t even come up in descriptions of the engineers’ discussions speaks volumes. This supports my original theory that they were an outfit which is good at winning projects via connections and box-ticking, but cannot actually execute any meaningful work nor adequately supervise those that do. This is modern business in a nutshell.

Secondly, the whole thing points to colossal organisational failure in the face of serious technical problems. There are a lot of people involved without clear roles and responsibilities with everyone talking, sharing opinions, and a*se-covering but nobody in charge and accountable (I suspect the investigation into the Boeing 737 MAX will reveal similar patterns). This represents a regression in terms of organisational and technical capabilities.

Now granted I am speculating but the incontrovertible facts are cracks were detected in the truss structure before the installation attempt and the engineers knew about them, but they went ahead with the installation anyway without bothering to close the road to traffic. It then collapsed and killed people. If this isn’t massive organisational failure then I don’t know what is.


29 thoughts on “Subcontract Bridge

  1. The project structure seems odd here. Someone designs the structure – FIGG. The design is handed over to the engineers who determine whether it can be built, and, if the design is feasible, exactly what materials are required and how it should be constructed. Then you appoint project managers and get the builders in. The engineers supervise every inch of the construction process. MCM seem to be the builders. Where was the engineering consultancy, the Ove Arup equivalent?

  2. Where was the engineering consultancy, the Ove Arup equivalent?

    It looks to me as though MCM were the overall project managers and builders, but subcontracted the design and engineering. For all I know they subcontracted the building too. There doesn’t seem to have been an overall engineering consultancy, unless MCM was it.

  3. With this, and the 737 Max, I am reminded of a visit to Rome. One of the Roman arches next to the Colosseum had some carvings near the top that are obviously better quality than ones lower down. Our guide explained that when the arch was built they re-used the better ones from an arch that had been 200 years old at that point. The poorer quality ones were new at the time – the skills available had regressed as Rome gradually deteriorated.

    I don’t think we’re quite at that level of regression, but it’s easy to see how it could happen. Diversity co-ordinators are not particularly productive.

  4. Is this behaviour (passing the buck to someone else) not the logical conclusion of the liability insurance/legal industry complex? That every producer of complex and potentially dangerous things will attempt to push as much of the legal liability risk onto someone else, a subcontractor basically, while keeping as much of the benefit of the contract/production for themselves as parasites? And as such there will be an increasing tendency for the actual work to be done in countries not the consumer country, because standards and oversight are lower there?

    There needs to be a change in the liability laws – it needs to be that if you contract to build a bridge for a customer, all the risk lies with you, as contract holder for bridge supply. If you get ABC Design Inc to design it, they are legally your employees for the purposes of designing that bridge and the liability for their design and calculation still lies with you. Similarly for the construction contractors etc etc throughout the process. You don’t have to employ them formally, but all the work they do is on your head, so you better watch them like a hawk.

    This would then mean that vertically integrated companies that could control all the parts of the process would be favoured, and the current model of splitting everything up into constituent parts would wither and die.

  5. There needs to be a change in the liability laws – it needs to be that if you contract to build a bridge for a customer, all the risk lies with you, as contract holder for bridge supply.

    That’s already the case (see BP over Macondo, for example). Only the outfit at the top then sues those lower down the contracting chain if they suffer a loss.

    Is this behaviour (passing the buck to someone else) not the logical conclusion of the liability insurance/legal industry complex?

    No, it’s the result of mangerialism of the sort that’s pumped out in business schools which sees “management” as a profession in itself, complete with every box-ticking exercise you can imagine, which is increasingly divorced from the actual work activities.

  6. Thanks for posting this which prompted me to check what has came out of the various investigations as to the cause of the failure. One of the issues that had me completely flummoxed at the time was how on earth a cable stayed bridge could have been commissioned without a pylon and cables supporting it!

    At the time of the failure it was shown and it still does appear and is drawn as a cable stayed bridge, but it wasn’t. That’s why I just couldn’t get it and thought that everyone should have been thrown in jail, but now I get it.

    “The full bridge project was styled to look like a cable-stayed bridge, with a pylon tower and high cables for dramatic effect. But functionally and structurally it was actually a truss bridge, with the spans being fully self-supporting”

    It appears to be fundamentally a design error, which doesn’t bring anyone back to life but I can at least now understand why this happened.

    It also looks like the authority slaps on wrists have been issued and the main contractor has also settled with common law damages as well.

    “On March 1, 2019 Munilla Construction Management, the main Miami-based contractor behind the pedestrian bridge construction, announced a restructuring and recapitalization of the Company through a Chapter 11 bankruptcy petition plan of reorganization. [76] The company reached a settlement deal with the victims and their families on May 2, 2019 that would pay up to 42 million.”

  7. When I’ve been involved in the planning, design and construction of mobile phone networks we have been classified as one big project rather than 100s of smaller ones and therefor subject to CDM. These regulations aren’t perfect but as far as I understand them they do make it clear who is responsible and that you can’t outsource H & S liability.

    They certainly concentrated my mind when I was the senior manager responsible and I made it clear to the Board that we weren’t cost cutting in that area.

  8. I don’t know enough about this to comment on the details.

    The projects I have been involved with generally do use specialist sub contractors – Structural engineers, architects, QS, M&E, electrical etc, so the number of subcontractors isn’t strange, and it’s easier to keep up to date in a speciality if that’s your business, than be employed in one company. I don’t know how the engineers would have signed off on something that couldn’t work – and FIGG seem to have a decent track record, so I don’t really know what went wrong – except that we won’t be reading more puff pieces about diversity in civil engineering projects.

  9. “That’s already the case (see BP over Macondo, for example). Only the outfit at the top then sues those lower down the contracting chain if they suffer a loss.”

    I would say that that is what has happened here.

    The main contractor will have the entire design and construct obligation and liability. If done properly this design obligation and liability can be sub consulted and cascaded down to the nominated design sub consultant. If it was done properly then the wording in the contractual documents must be spot on and the deign subconsultant will have had in place Professional Indemnity insurance which if it was a design error is where everybody would be hitting.

    Lets just say that the entire design was subconsulted properly and insured properly and it was a deign error at the subconsultant level although I doubt that the insurance level would be anywhere near the payout level,based on the contract value only being $10m.

    If the main contractor was properly inured then they would have all of their liability unionized such that each policy can act in aggregate with other eg their general liability (20m), construction work (10m) liability levels can be used on top of the consultants PI (10m) to be above the eventual pay out amount of $42m.

  10. @tolkein

    Having read that article I would say that causation was firstly a design error (very had to detect on site) and high risk stressing work taking place over live traffic.

    It looks like there is a bit of ducking and diving on lane closure permits. It is highly irregular for post tensioning work to be undertaken over live traffic, that is a bit of a no no in my experience and not something that would be done..

    So if the above is reflective, then the death toll could probably have been prevented if a simple exclusion zone was put in place during the post tensioning work, which has very high energy transfer loads being applied.

    Yes it still fails but it doesn’t collapse on anyone or pull anyone into it.

    A simple and industry standard safety isolation control was not in place here, from what I can see.

  11. One thing that jumped out at me when I read the ENR link I tweeted you was the lack of female names. In particular the lack of a mention a certain Leonor Flores

    I recall that the original MCM/FIU PR about the bridge (the ones before it collapsed) had lots of guff about female leadership/empowerment and other HR diversity buzzword bingo. For example this which had lots of heartwarming details about how Ms Flores’ daughters were being inspired watching the bridge their mother was project executive for.

    Yet it seems that when it was time to actually screw up the design/construction all that was outsourced to (not very competent) males. The ladies seem to have vanished from the picture. How odd. Maybe they were just there as PR flim flam? or maybe they were too busy holding meetings to actually get involved in actually making decisions?

    Very odd

  12. I am into bridges, engineering and urban architecture and very much against what they done here in attempting to make it look like a cable stayed bridge when it was not. There are many other options they could have done to make it architecturally pleasing none of which would involve making it look like another type of bridge that it is not, which would add a significant unnecessary cost, that is not quality and is not civil engineering in anyone’s books.

    Compare this scheme to one that I encountered on a recent trip in the Balkan’s. See post below that I wrote for some of my colleagues about this bridge it’s engineer and his very real and still functioning civil engineering masterpieces.


    Leaving Ljubljana shortly and heading for Vienna the last stop of my trip. So that’s me technically leaving the Balkan’s when I depart from here in Slovenia.

    Ljubljana is a great spot another one of those cities that you can easily cover on foot. Like Zagreb, Ljubljana was originally founded and civilised by the Romans.

    That shot I posted before of the three bridges, they were designed by Jože Plečnik a Slovenian legend.

    He studied architecture in Vienna with Otto Wagner and the other leaders of the day, done a lot of major work in Prague and was in the running to be the chief architect of the Austrian Empire but being a Slav made it impossible in the end.

    He returned to his home town of Ljubljana at the invitation of the Lubijhana University and done a huge amount of work here.

    See the next photo which shows some balustrade of the three bridges that I posted about before and in the background the city market place that he also done.

    He selected this spot for the marketplace because it was in the shade and the river cooling effect which meant the the fish and meat on sale was kept cool and fresher longer in the vey hot summer that they get here, ice was not an option.

    The other thing was, that all of his major projects were all done with a very low budget. He apparently devoted his life to his work, had no other interests, was a priest, smoked six packs and drunk seven double espresso a day and lived in a tiny bedsit.

    The third bridge balustrade, if you look at it closely, you will see that it was made of reconstituted stone and not marble!že_Plečnik

  13. Nice shots, the river embankment and library in your album were also by Jože Plečnik and love the legendary Ljubljana Dragon of Jason and the Argonauts fame!

  14. I have no masterful insights, but can contribute a few related links:

    What is FIGG Bridge Engineers’ role in this project?
    FIGG Bridge Engineers, Inc. is the designer of the bridge, working for MCM. The project is part of a $19.4 million U.S. Department of Transportation TIGER grant, and was bid competitively using design-build procurement by Florida International University.

    OK, so something called a TIGER grant is involved. According to this page:

    TIGER means (Transportation Investment Generating Economic Recovery)
    This being a US Department of transportation project intended to pump $600 million (US) into transportation projects in fiscal year 2014. I haven’t dug far enough to find them, but I know perfectly well that the feds will have had a huge mass of rules, regulations, policies, procedures, prohibitions, and requirements attached to each grant. I don’t know at this point if one of their conditions may have affected the design.

    My fellow poster francisT contributed the link:

    Something I found interesting is that this article states:

    Twelve-year-old Michelle Flores shared a special moment with her family at FIU this past Saturday: She and her sister Gabriela joined their parents, FIU alumni Leonor and Henry Flores MIS ’01, to watch a 950-ton section of a pedestrian bridge swing into its permanent position across Southwest 8th Street.

    Leonor Flores ’98 is a project executive and one of 63 FIU alumni who work for MCM, the construction firm building the FIU-Sweetwater UniversityCity Bridge, … She was excited to share her work with her family, especially Michelle, who is interested in STEM…

    Michelle said she might want to follow in her parents’ footsteps and go to FIU when the time comes, and that it was fascinating to see her mom’s work in action. “I’m interested in the architecture and the design of the bridge, and the math portion of it,” she said.

    Said Leonor: “It’s very important for me as a woman and an engineer to be able to promote that to my daughter, because I think women have a different perspective. We’re able to put in an artistic touch and we’re able to build, too.”

    I wonder if this means that a woman was involved in this business where they stuck suspension cable on top of what is not a suspension bridge? I do know that it is beastly hot in South Florida and have to wonder why they didn’t make that overhang wide enough to shade the bridge properly during the day.

    There is a note attached to the page stating

    UPDATE, March 16, 2018, 11 a.m.: To clarify, Leonor Flores did not work on the FIU-Sweetwater UniversityCity Bridge project in any capacity.

    This suggests to me that either the original article was deliberately misleading, or that FIU is working hard to retroactively erase Ms. Flores from the picture, a la the way the Soviets removed politicians from photographs if they fell from favor.

  15. One more link:

    For readers who are not familiar with the American National Transportation Safety Board, They are a federal agency that is charged with investigating accidents that involve transportation.

    Their reputation, at least as I know it, could be compared with having a glacier come through your property. Nothing happens quickly, they cannot be stopped or diverted or distracted, they will grind through *everything* all the way to the bottom and when they someday recede, they will leave exposed the bedrock truth, the root and immediate causes, without political considerations, without pity, or mercy or sympathy, just the truth however good, bad, or ugly it may be.

    These are people who can start out with twenty thousand pieces of burnt and twisted metal scattered across three different states and five or ten years later they will have it all put back together in a hangar somewhere and they will be able to describe in excruciating detail the exact chain of failure for every system and subsystem.

    Kind of sounds like engineers heaven, no?

    What they state in the linked article is that all the samples of materials they pulled from the wreckage have been found to be of good quality, and their opinion so far is that this was a design failure.

  16. One should not overlook the fact that this project was done for an institution of higher education, and one with a dodgy name at that.

  17. @Ken – “What they state in the linked article is that all the samples of materials they pulled from the wreckage have been found to be of good quality, and their opinion so far is that this was a design failure.”

    I think that it is a safe assumption to make that in civil engineering projects in the developed world that it would be extremely unlikely for concrete strength, rebar strength and tension rod strength or any other critical quality attribute of these structural members was found to be critically nonconforming. Its probably harder to introduce inferior materials than it is to install complying materials.

    This design issue on tte cross flange, shouldn’t have happened, designers are human and do make mistakes, so what level of checking, modelling and validation was undertaken will be under the microscope now. Not forgetting that the design would also have a fairly significant factor of safety applied ie the dead and live loads that the bridge was designed to withstand would have been far higher than what was required during construction and in service. Apparently it was a novel design and the university had an accelerated bridge brand, whether this impetus somehow meant that the required fundamental design calculations and assumption checks were ignored, bypassed or overridden would also be under investigation. Like all of these things I think we can assume that none of the design engineers went to work one morning with an objective of designing a bridge collapse. No doubt some of those involved will be taking this very bad and will be receiving counselling.

    All the public that were killed, were inside their vehicles that were stopped for a red light under the bridge when it collapsed. It is a terrible irony that the public were obeying a public safety control, a red light, which contributed to their death, when a very simple and normal public and construction worker safety control ie no stressing work to be undertaken above traffic was not in place, the public have right to expect controls like this to be in place. It really is a tragedy that this one obvious measure would have meant that the design flaw, the non detection on site, the eventual failure and collapse would not have resulted in any injury or death if it were in place.

    Whomever made the call to carry out high risk post-tensioning work, particularly on the main web of the beam that fell, above live traffic, made a very serious error of judgement here. Which is why I can see that there is much ducking and diving going on on the lane closure issue.

    Next time you are held up at some innocuous road work where say they are doing some work on the hard shoulder and have taken out two adjacent lanes as a buffer zone, arguably overkill. Think about this situation whereby traffic was allowed to park up underneath a very heavy piece of concrete, that was not complete and full of potential energy (ie gravity) and was being subject to transfer of extremely high man made energy forces.

  18. Whomever made the call to carry out high risk post-tensioning work, particularly on the main web of the beam that fell, above live traffic, made a very serious error of judgement here. Which is why I can see that there is much ducking and diving going on on the lane closure issue.

    …Think about this situation whereby traffic was allowed to park up underneath a very heavy piece of concrete, that was not complete and full of potential energy (ie gravity) and was being subject to transfer of extremely high man made energy forces.

    Worth noting there was a similar collapse of a bridge during construction in Japan in 2016 where the road below was closed. As a result the only deaths / injuries were in the construction crew.

  19. Yet it seems that when it was time to actually screw up the design/construction all that was outsourced to (not very competent) males. The ladies seem to have vanished from the picture. How odd. Maybe they were just there as PR flim flam? or maybe they were too busy holding meetings to actually get involved in actually making decisions?

    Oh no, within hours of the collapse the FIU admitted that the woman they’d been parading around in front of the bridge during photoshoots actually had nothing to do with it.

  20. Whomever made the call to carry out high risk post-tensioning work, particularly on the main web of the beam that fell, above live traffic, made a very serious error of judgement here.

    You would never, ever install a bridge above live traffic even if you were 200% sure the design and installation method were sound. Like standing under a load being lifted on a building site, you just don’t do it. A simple risk assessment would have told them this, but Americans prefer the box-ticking OSHA approach to risk assessments.

  21. The joys of retirement have provided me with the time to take a closer look at this including photographs of the cracking, the construction sequencing and what was going on on the day of the collapse.

    The bridge beams, deck and post-tensioning was done prior to it being placed in-situ. So in theory the structural member was complete, when insitu, which on face value is acceptable and therefore it would be okay to have live traffic flow underneath.

    The collapse happened after the deck was installed and no one knows or is saying what work was going on that day and immediately prior to collapse. There are many contemporaneous records but no record of activity that day, although stressing jacks were in use and may have been in use to alter another section of the simply supported structure. So the stressing or not and to what extent and on what structural members is not in the public domain, nor was their a permit to undertake stressing works over live traffic issued either.

    What I have seen that is extremely alarming and way above anything that any structural engineer would not immediately identify as a critical situation is the extent and size of the cracking that was observed in the vicinity of the section that failed. When I read the transcript of the call on the wiki article above, I thought to myself, yes, cracks do occur a lot in reinforced concrete, they quite often self heal and on their own dont necessarily indicate a problem. But looking at the photos of the actual cracks taken that morning and prior to the collapse, they are way longer, wider and deeper than anything you would expect to see. In bridge construction and when doing an integrity assessment you normally measure crack size using a transparent crack gauge with printed sizes in microns that you lay over the crack to the closest fit to measure its size in microns. The cracks in questions traveled right through the section, at an angle that they shouldn’t have and as far as width and depth you could jam an iPhone in them. There is no way anyone would have considered them as anything else but the biggest warning bell going off!

    I take back what I said earlier about sometimes it is not easy to detect deign issues on site, these cracks were way beyond the pale.

    The record doesn’t state what was happening at the time but the view is that they were doing work to address the cracks, with stressing jacks somewhere else on the deck. VSL the stressing subcontractor was also sued in the actions.

    So the post-tensioning was not as in your face as first thought, but still a no-no over live traffic and the cracks have now been promoted to a complete and unambiguous massive indication of a major structural problem occurring in real time. It is unbelievable that the cracks were not seen as a major warning bell, flashing light, do not pass go alarm blaring at anybody that was on site.

    The right thing to do here, would be to put some temporary props in place, a relatively easy and quick way to ensure that the structure was safe and allow traffic to pass under and the engineers to get to the bottom of what was causing the cracks to occur.

    The warning signs were there, a temporary solution could easily have been put in place and disaster and death averted, if anything, it gets worse the more you read.

    See crack size here, before collapse.

  22. See image of a crack gauge similar to what I used in bridge inspections in Australia. The one below is imperial and what the guys in the US would use to measure crack size in concrete in its plastic (set) state.


    Concrete Crack Width Ruler | Range: 0.004-0.100″ / 0.10-2.50mm | Elcometer E143

    Range: 0.004 – 0.100″ (0.10 – 2.50mm)

    This simple crack width ruler has been designed to provide inspectors with a low cost alternative to a graduated microscope for determining the width of a crack in concrete or other building materials.

    Similar in size to a standard credit card, this transparent concrete ruler is marked with a range of graded lines, each with a specified width.

    To use, position the gauge over the crack and identify which line is a similar width to the crack. Read off the width value.

  23. Update.

    A new report has been recently issued and is linked below for those interested. Just skimmed it now and it goes along way to answer many of the questions asked by others on here and speaks for itself. See the crack pictures, particularly on page 59 and other evidence of movement, its unbelievable and defies reason that nobody reacted to these visual in your face warning signs at the time. It also covers construction activities underway on the day and yes they were in fact stressing tendons prior to and at the time of failure. This activity was not in the design nor contemplated in the installation plan.

    FIGG rather than having no comment and quite astonishingly are arguing semantics on this report, as if the fucking cunt of a thing didn’t end up in a pile of rubble, killing six people and badly injuring another. Unless there is something else still to come out, that we are not yet aware of, their response is disgraceful, unacceptable and a blight on the civil engineering profession.


    In a statement to ENR, FIGG disputed OSHA’s findings, calling the report “factually inaccurate and incomplete” with “errors and flawed analyses.”

    The OSHA FIU Pedestrian Bridge report “does not include an evaluation of many important factors pertinent to the construction process leading up to the accident. Additionally, it has not been reviewed by any other entities involved in the accident investigation. FIGG disagrees with the conclusions in the OSHA report.”

    “The Tallahassee, Fla.-based engineer added: “As a party member to the NTSB (investigation) process, we are not able to elaborate further, but at the appropriate time the facts and the truth will be released to the public.”


    I seen elsewhere that FIGG’s insurers were attempting to decline cover for this incident last year (which can only mean gross negligence), not sure how this was resolved and their owner/leader is a female engineer, she inherited the firm from her father.


    “The company was launched four decades ago by Eugene Figg, Jr., and is now run by his daughter Linda Figg. She works out of the same office her dad once worked in. They have built and managed bridges in 42 states and six countries, and won more than 355 awards of excellence.”


    Extract of some of the key findings from the new report:

    10. Conclusions

    As a result of the investigation, OES concludes that:

    1. FIGG Bridge Engineers (FIGG) ,the Engineer of Record (EOR) failed to recognize that the bridge was in danger of collapsing when he inspected it hours before the collapse. The concrete truss had developed numerous wide and deep structural cracks jeopardizing the integrity of the bridge. The EOR should have immediately instructed that the bridge be shored at appropriate locations and SW 8th Street be closed. At the time of collapse, the post-tensioning bars were being re-tensioned at the specific instructions of the EOR.

    4. The magnitude of the cracks warranted that SW 8th Street be immediately closed, and the concrete truss be shored and supported at multiple intermediate locations to reduce the loads in the north diagonal and the node until final evaluations were done and remedial
    measures implemented.

    8. The evaluations of the cracks by the EOR, and his recommendation to re-tension the post-tensioning bars of diagonal 11, were not included in the original design and therefore should have been subject to peer review.

    Investigation of March 15, 2018 Pedestrian
    Bridge Collapse at Florida International
    University, Miami, FL
    U.S Department of Labor
    Occupational Safety and Health Administration
    Directorate of Construction
    June 2019

  24. Bardon,

    Thanks for doing more digging, the crack pictures in the OSHA report are mind-blowing.

    I don’t understand how anyone would not decide to at the very least close off the road while trying to figure out if it were dangerous or not

  25. @francis

    Cheers and your welcome, I live and breathe this kind of stuff and its a productive use of my free time. As I said before I am a bridge nut and have built many myself and as I posted on here before one of them held the world record for the highest span as well, yes that may be bragging but beat it if you can. This particular case is very interesting for me because I was recently involved in preparing a budget proposal for a pedestrian crossing in an urban setting and for an educational establishment.

    My proposal whist not successful has been parked up, you never know it might get legs but I doubt it. I won’t mention the price here just in case it gets legs in the future, but I do know that it would be similar in cost to an overpass.

    The proposal was for a pedestrian “underpass” to convey pupils between school facilities that were separated by a very busy four lane main road and intersection. The pupils are crossing using the existing traffic light direct crossing method and the school was looking into eliminating the need for their pupils to cross this way. This meant that an “at grade separation” crossing would be required which is either an overpass or an underpass. People prefer to cross directly at designated crossings, with overpasses and underpasses being least preferred in that order. Underpasses are less preferred due to a perception of access, safety and crime and an aversion to going under things. I am involved with a Qatari firm that have constructed underpasses in Doha for the huge new rail systems that are going in there, pedestrian underpasses are becoming more common place particularly in rapidly growing urban corridors, with lower crime and higher socio-economic rates. If you go to the 2022 World Cup in Doha, I guarantee that you will be spending some time walking through pedestrian underpasses.

    The particular proposal was for The Scots College a private school in Sydney a very affluent and leafy inner-city suburb. I knew that we were up against a pedestrian overpass and I knew roughly how much that would cost to install. The proposal was designed to combat the underpass negative perceptions and also to take out the visual risk that plonking an overpass in this heritage listed setting would definitely introduce. Plus, the dedicated underpass would mean that the pupils could traverse between the facilities underneath the busy Victoria Rd without having to share an overpass with the public which would be a requirement if they put one in.

    It was 44m long and due to the school being built on a hill, the levels worked such that it opened up into their main courtyard and at the same level and could have been built with minimal disruption, zero impact on traffic, zero risk to the public. There was a tiny window of opportunity to work in the school facilities and although if you look at the linked plan below and see tons of space there was absolutely no infringing on their sports fields allowed. My partner was keen to be the first to use this methodology in Australia and I can tell you that there are many others looking into it now and I wouldn’t be surprised if there are some underpasses now being built as part of the major public infrastructure that is going in. This proposal is two years old now and I am no longer in that space. See picture below of a nice pedestrian underpass in Singapore, utilized in an effort to overcome the objection to dark, dingy, smelly, undesirable underpass perceptions that exists.

    Incidentally a pedestrian underpass would have been viable in the Florida University including the adjacent canal crossing. It would have also overcome the hurdle that they had due to the long span needed to get over all of the existing highway lanes with no mid span support. I know Florida fairly well and have been there a number of times and have studied their town planning as an example of a urban planning in a rapidly growing developed area. I do think though that the negative perception of an underpass would be a major hurdle there due to the lower socio-economic folk, the fact that it would need to be shared with the public and the length, this overpass was being touted as gentrification of the area as well. I am sure this disaster will be used now in pro-underpass proponents marketing documents on the pros and cons of an underpass compared to an overpass.

    Nice pedestrian underpass picture

    Plan showing school and underpass alignment

    We have studied the site, the existing documented information, the constraints and the student pedestrian flows and have developed an underpass proposal that we considered befitting of The Scots College historical and heritage style facilities. Safety of the patrons, pedestrians, utility owners and vehicular traffic flows were the main acceptance criteria in arriving at our conclusion. Our proposal is for a 44m long underpass constructed using a canopy tube arch support system, a proven technique that we are completely familiar with. …………….

    Located beneath the T Junction of Victoria Road and Gingullha Rd at The Scots College 53 Victoria Rd, Belvue Hill, NSW, 2023. This project involves the design and construction of a dedicated 44m long pedestrian underpass. The underpass alignment will traverse beneath a busy road intersection within a sandstone substrate. The alignment and single launch shaft location was established based on an assessment of the site and the various options in order to identify the safest and shortest crossing method that provides for the existing and any potential increased pedestrian traffic flows between the college facilities that are currently separated by Victoria Road.` Pupils currently utilise the existing intersection pedestrian and traffic control to walk between the two separate locations during their school day. The main paved courtyard was identified as the best and safest launch position and preferred approach to the excavation, with no overhead power lines and sufficient surface space to have the working platform in use alongside properly protected students, teachers and other pedestrian traffic.

  26. Forgot to mention in my post above (two hyperlinks awaiting moderation) that this concrete truss structure design has never been used before anywhere in the world. There are thousands of steel trusses in use that also have members running down each side, meaning that if one member fails the bridge does not collapse as was the case here.

    The main driver for this novel approach to truss frames was that they wanted the truss members to align with the fake cables in the overall fake cable stayed appearance!

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