Why Buildings Fail – Sleuthing Out the Causes

Why Buildings Fail - Sleuthing Out the Causes

(Note: This discussion post is aimed at students in the Building Failures and Forensic Techniques class in Architectural Engineering at Penn State)

One of the best ways to learn about the failure of buildings and related systems is to look to the vast numbers of examples and case studies that have been written on the topic. Two older, but great introductions to the topic, include the articles “Sleuthing out building failures” (Ref. No. 1-1, Architectural Record, July 2006) and “Sleuthing the Mundane and the Catastrophic”, (Ref. No. 1-2, Architectural Record, Oct. 2006.) Both of these articles delve into historic case study examples, failure trends and statistics, and structural and architectural system failures.  Some of the causes of these examples seem obvious and you have likely seen them before; leaking windows and roofs, deteriorated concrete sidewalks and steps, space temperature control issues, bouncy floors and sagging floor joists to name but a few. Other failures are far more catastrophic. Pieces of masonry facades falling off buildings, collapse of bridges or gas station canopies due to vehicle impact on up to partial or complete collapses of a building leading to the loss of life.   The Kansas City Hyatt Regency Hotel Walkways, Pier 34 nightclub in Philadelphia and the L”Ambiance Plaza lift slab construction collapse in Bridgeport, CT are unfortunately but a few examples of this later category.

As the Sleuthing the Mundane and the Catastrophic article notes, falling facades can be catastrophic but the much more common and mundane problem with facades is water infiltration. Statistics, especially recent and accurate ones on building system failures are difficult to obtain. It is safe to say however that relative to the more routine failures, water penetration and resulting damage to roofs and facades results in the highest number of legal claims and amount of claim damages.

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What causes all these different types of failures? As noted in the two articles previously mentioned and the Why Buildings Fail discussions in class, the reasons are quite varied.  It is worth noting that often it is not a single cause but a situation when several items come together in a negative fashion with the result of over whelming our “safety factors” and the built-in reserve capacity of materials and systems, sometime in conjunction with poor detailing or construction practices.   For example, consider the case of a two story parking deck in the northeastern United States.  An initial water resistant coating had been specified but it is not clear if it was ever applied or maintained.   Corrosion in the reinforcing weakened the concrete deck resulting in a reduction of overall load capacity.  However, under normal automobile loading the deck was performing from the perspective that it was resisting the applied loads.  The upper deck was directly accessible from grade from an alley on the high side of the structure and no oversize or height barriers were in place although there was an indication that some sort of barrier had been present at one time.  On the day of the failue an RV pulled up the alley and swung onto the upper parking deck.  The resulting wheel load was enough to push the deck over the limit and one set of wheels on the RV punched through the concrete slab.  Fortunately no one was hurt but the combination of lack of care and maintenance leading to corrosion and the oversize / overweight (for that facility) RV that entered because the security bar was not in place combined to cause the failure.

Readers of this post and the referenced documents are asked to provide comments, discussion and suggestions / solutions to the building failures problems we encounter on a daily basis as an introduction to more detailed study of these topics throughout the coming weeks.

mkp

 

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69 Responses to “Why Buildings Fail – Sleuthing Out the Causes”

  1. Brendan B
    September 8, 2016 at 1:39 am #

    In wrapping up our discussion on why buildings fail, I think the first sleuthing out building failures article offers an interesting perspective under the “What architects can do to prevent building failures” article. The main argument of liability has been between the EOR and contractor, but this writer explains how a third party, architects, can also be held accountable.

    One of the topics include making sure incompatible metals and other materials causing interactions such as differing rates of expansion and contraction are not combined. A common theme for failure has been relaying the drawings from the office to site, ultimately leading to failure during construction. By removing any worrisome components of construction, it would make the contractor’s job less confusing.

    Of course, it is still the engineers responsibility to supervise the contractors, but reducing any confusion will make the process easier for all parties involved. This is certainly something to keep in mind as just as there is usually more than once cause of failure, there can be more than one individual to prevent this failure.

  2. YusufA
    September 6, 2016 at 8:51 am #

    Having carefully studied the first three case studies, It seemed pretty common that a lack of proper supervision has led to most of the collapses we have seen and discussed in class. I do not just mean supervision by the Engineering consultant but also with the Government agencies in charge. Contractors also seem to be more concerned about cost savings than human life savings as it was apparent in the case of the Save-On-Food supermarket roof collapse which was initially awarded due to the low price bidding.

    Another serious issue which is also supervision related is the on-site construction supervision and lack of communication among all engineers on a project. Information related to the project should be passed around to all engineers timely before any major decision is being made. This should however be followed by an inspection of the last reported work. It should be strongly enforced that no change is done to any designed member on site by the contractor and anyone found guilty should be prosecuted.

    An update on the code is another very important part which needs to be addressed because there is no way of avoiding future failure if the rules are not enforced. As in our case, we are priviledged to take the AE 537: Building failure classes and see some of these failures and build an understanding of the causes which we would in turn try to avoid when we go into the industry. Another engineer from another university may not have had the opportunity to learn this and would turn to the OSHA erection guidelines.
    Therefore regular updates based on lessons learnt from each failure is very important to progress in the reduction or eradication of future failures.

    • Yemi O
      September 7, 2016 at 5:24 pm #

      Yusuf,

      I completely agree with you especially with regards to the save-on-food supermarket roof collapse. I wonder how much ethics plays a part in some of the decisions made before and during construction. I can’t help but think that sometimes the engineers, contractors,etc know the right things that need to be done to fully ensure safety and instead turn the other cheek and let things slide, either for the reason of cost savings or maybe even for the reason as simple as an issue being “downplayed” as non-pressing.

    • Shane M
      September 7, 2016 at 11:02 pm #

      Yusuf, the point you bring up about the concern of saving money during design is very important. The thing that keeps companies in business is their ability to turn a profit. This is a very dangerous habit that unfortunately some engineers fall into. These people may be pushed to meet multiple strict deadlines but that should not come at the cost of providing a safe design. I believe there should be greater enforcement on engineers to not cut corners or push boundaries during construction. But I would not stop at the engineers, the owners and other parties involved should be thoroughly informed on how budgets should not force their designers to bid too low. This type of thing should be addressed at the start of any project.

  3. philr
    September 5, 2016 at 7:11 pm #

    Parking garage collapse today while being constructed in Tel Aviv. Another progressive collapse. Several articles out there, but this one has the most pictures. Misc (and probably very premature) discussions by government officials speculating on quality issues a potential cause.

    http://www.jpost.com/Israel-News/Initial-report-Multiple-people-injured-in-Tel-Aviv-crane-collapse-466908

    • mkev
      September 5, 2016 at 8:50 pm #

      Bad weekend for failures. A number in the news. The Pittsburgh Liberty Bridge caught fire due to a construction accident (sparks from a welder) caught materials on fire. Temperatures reported to have warped a major steel beam. http://pittsburgh.cbslocal.com/2016/09/04/penndot-announces-timeline-for-liberty-bridge-repair/

    • Yingzhe You
      September 7, 2016 at 3:40 pm #

      More investigations have been made. Construction company reduced the building costs by 2 to 3% by using an architect instead of an engineer and engineers said that this caused the building failure.
      http://www.ynetnews.com/articles/0,7340,L-4851055,00.html

      • mkev
        September 7, 2016 at 10:29 pm #

        Nice update article Yingzhe. My favorite quote in the article “…an engineer—who is basically a construction worker whose only responsibility is to make sure that the building won’t collapse.”

        Well, it collapsed now didn’t it! #mathisimportant

    • Mehrzad
      September 8, 2016 at 4:29 am #

      Lack of enough inspection,
      [“The country’s Economy Ministry has jurisdiction over construction safety enforcement, but with only 18 supervisors for about 13,000 building sites, Israeli media reported that more than half of all sites remain uninspected.”]

      negligence of warning indications,
      [“Man Trapped in Tel Aviv Collapse Rubble Told Wife of Safety Flaws Just Days Ago”]

      unqualified project manager,
      [“Danya Cebus CEO Ronen Ginsburg vehemently denied a report in the country’s largest newspaper Yediot Ahronot that he said in a 2013 article that the company decided to have an architect rather than an engineer oversee the project, as a measure to cut costs. Ginsburg claimed the story author had misunderstood him.”]

      and structural/construction shortcomings, as suggested in the first link below, such as
      1) reinforcement deficiencies at post to slab connection (hence punching shear) likely by the contractor and not the designer,
      2) possible settlement due to usage of mat foundation on the prevalent local soft soil instead of pile foundations used at an adjacent hospital, and
      3) minor factor of insufficient concrete strength development in spite of absence of critical construction loads

      are among the reasons theorized for this progressive failure.

      http://www.haaretz.com/israel-news/.premium-1.740664
      http://www.enr.com/articles/40177-multiple-probes-under-way-into-fatal-israeli-site-collapse

  4. Joe H
    September 1, 2016 at 9:05 am #

    In keeping with our class discussion on never assuming what causes a failure, I was quite intrigued by one of the failures described on pages 6-9 of the second reading (the building name and owner are not revealed). This was another moisture issue in a heavy timber and masonry construction. Some normal sources of water filtration were checked, such as mechanical systems and condensation, but neither of these were the cause. Eventually, it was discovered through interviews with the construction workers and an asphalt investigation that the wood was wet during the construction process. It took workers 2-3 coats of paint to achieve the desired look, when only one was specified.

    I think this example plays well into my previous comment on moral standards as a worker. The construction workers doing the painting took it upon themselves to try to make the building look good, even when it meant going beyond what was specified. Because of this, investigators were able to use this information to piece together the puzzle.

    This is also a great opportunity to learn from what may seem to be a mundane construction issue. I think it’s safe to say most people would blame the paint, not the interior moisture content of the wood, when one coat wasn’t enough. However, if this issue arises on another construction site, they have this example to hopefully prevent the issue before the building is in use.

    • Joshua Z
      September 7, 2016 at 8:39 pm #

      Joe,

      I wanted to add on to your comment of morality, as you mentioned in this post with the workers taking it upon themselves to go beyond what was specified, as well as in your previous post when you mentioned that you believe moral obligation should outweigh the legal obligation, like in the cases of following construction documents or performing inspections even when it isn’t stated that there needs to be some.

      My two previous posts about buildings had a focus on negligence and how the mistakes that were made were a result of lack of oversight and communication, as well as just general carelessness in design and construction. It is good that there is now a precedent in the case of this failure because of the wet paint. However, this precedent only came around as a result of a failure. So, does that mean in order to solve new construction problems, we need failures so that we know not to make the same mistake? Is there a way through testing and simulation that we, as engineers, can determine what problems might happen before they do? It would save a lot of time, trouble and money. Are we morally obligated to try to find these problems before they occur, so that we may minimize accidents and injuries?

  5. Yamile R
    September 1, 2016 at 8:01 am #

    In learning about the reasons of building failure, the idea of this being a combination of situations rather a single cause is redundant through all cases. As we have seen in most of the examples, the collapses occurs under circumstances that, considered in the initial design or not, happened after a series of events.

    It caught my attention that two of the example cases happened during construction; in my opinion this could only mean that something is definitely wrong in the structure design, the construction process or the interpretation of the former. Some of the other examples discussed in class consisted of loading not previously prevented, most likely a rare situation that did not have a high probability of happening. This does not make the failure acceptable, but from my point of view, more understandable.

    About the Skyline Plaza, my main concern is not the failure on the 23rd floor, but the progressive collapse resulting from it. Structural designers, while evaluating the system as a whole, must consider the possibility of failure in a portion of it. For instance, the fact that WTC (built the same year of the Skyline Plaza) was designed to withstand the impact of an airplane, and prevent a total collapse of the building due to this cause is a good example. And again, did not include sufficient fire-suppression systems, not considering that part of the building could suffer a major fire, which was the main reason of the collapse.

    • mkev
      September 7, 2016 at 10:33 pm #

      Yamile,
      Thoughtful comments.
      One item on the Trade Centers, however. There was both passive and active fire proofing in the building. The initial explosion is believed to have destroyed the spray on fire proofing and also severed many of the sprinkler lines that were in place.

  6. Brendan B
    September 1, 2016 at 2:12 am #

    After doing some additional research on progressive collapse, I found another case where there was a lack of communication between the EOR and GC, such as the L’Ambiance Plaza in Bridgeport, Connecticut which killed 28 construction workers. Technically the exact cause of collapse was never decided, but there were several theories that were proposed. Several of these theories included improper design of post-tension tendons and the jack rod and lifting nut slipping out due to an overloaded steel angle at the building’s most heavily loaded column.

    This collapse caused people to question why connection details were not carefully relayed to the GC. If the engineers had taken a site visit such as the skyline plaza case, its possible that the defects for the connections could have been detected. This once again shows the importance of knowing what you are responsible for and making sure to follow up during construction. Misinterpretation of CD’s between the GC and EOR seems to be a running theme in these failures, and making sure everything is conveyed properly could certainly help prevent future problems.

    • Ommar E
      September 7, 2016 at 11:50 pm #

      Proper communication between those many teams involved in building’s design and construction is key in preventing many building failures. As you have indicated loss of lives in this accident was huge and could have been avoided if thorough and effective communication had taken place.
      The second point about lack of keen follow up shows that even properly designed buildings could face failure during construction or afterwards if these designs are not implemented correctly. It is always the weakest link that can bring about failure or collapse. That weakest link does not have to be a physical one. A failure in following proper procedures could constitute one.

  7. Di W
    August 31, 2016 at 11:58 pm #

    A small point

    The structure may be designed and built properly but if it sits on a bad foundation. Failures that occur because of foundation problems may be even worse. A whole residential building fell down entirely in Shanghai, China, 2009 just because the soil that the building sat on was very weak. Geotechnic engineers, at that time, underestimated the shear strength of the soil.

    Geotechnical investments, to some extent, are the first insurance that keep the buildings stand. However, these are the most difficult parts in a building construction. The soil has too much indeterminacy. The soil type, compressibility, strength, plastic, permeability, expansion and collapse potential, consolidation, etc. These require the geotechnical engineers a lot. So the foundation failure should be the first thing that we need to review in buildings failures.

    • Yingzhe You
      September 5, 2016 at 11:15 pm #

      I’m familiar with this case. It’s a typical building failure case caused by the unprofessional behavior by the construction workers.Instead of removing all the soil away, they stored all of them near the high-rise building which was under construction. The 30 feet “hill” caused the difference between two sides of the building foundation, and that was where the shear came from. We’ve got regulations, and we have the training class for workers. In order to save money and time, they chose to disobey the rules. So I think we need more and strict supervisors and regulations to prevent this kind of tragedy happen again. And the foundation was not designed properly. I agree with you that we need to put more emphasis on the foundation designing compared with the structure up the ground.

    • philr
      September 6, 2016 at 2:27 pm #

      Di mentions soil issues as an important factor in structural integrity. I lived in Hong Kong for a couple of years, and they have continuously built into the harbor that separates Hong Kong Island and Kowloon. I have always wondered what would happen to those structures in a earthquake, particularly the foundations.

      Building on sand fill in a saturated environment is a recipe for liquefaction during seismic events. This happened in the Japan event about 50 years ago, when entire apartment buildings built on reclaimed , saturated cohesionless sand turned over due to the “quicksand” that developed during the event.

      https://en.wikipedia.org/wiki/Soil_liquefaction

    • mkev
      September 7, 2016 at 10:36 pm #

      Di,
      Good points. But even in the failure you are using as an example, there was the contributing factor of rain / water saturation of soil, improper excavation in one area and stockpiles of soil (added load / pressure) in another. So, while you are correct, we are back to the discussion on multiple errors ganging up on us to cause the collapse rather than just one single element.

  8. Shane M
    August 31, 2016 at 8:45 pm #

    Reading through the supermarket roof collapse article I recognized some familiar mistakes made by these engineers. Some of these mistakes are ones that we have covered in class such as the excess concrete placed during the construction of the IST building. There was an obvious lack of knowledge and communication between the contractors and the engineers. But unfortunately in the case of the supermarket, there were many more mistakes made throughout both the design and construction processes. I would say that this lack of care, coordination, and sometimes knowledge still exists today. During my previous summer internship I worked for a structural consulting firm that dealt with both design and some forensics engineering. Some of the engineers in the office would talk about how they had to take over or revise a design because the previous EOR mismanaged their end of the project. There was even a case where we had to tell an outside engineer that they needed to design for snow loads, apparently they never did this. Hearing about these types of stories really makes you wonder if most engineers understand the consequences of their actions. In this case it could have been that the project team saw that they were not going to make much profit from this job so there might have been a lack of motivation to coordinate the project. On the other hand these engineers and contractors seem to have just lacked the knowledge and qualifications to do the job. An engineer not properly educated in steel design could easily miss the possibility of lateral torsional buckling especially in a structure like the Gerber system where unlike a typical simple span, there is the negative moment occurring at the interior column. The quick change to this more economical design could have led the engineer to select the smaller beam size because they knew the system was meant to reduce the required beam size. So in this case they could have ignored the strength check, but with the addition of the miscalculated loads the already incorrect design had no chance of working.

    • Rebecca M
      September 1, 2016 at 6:04 am #

      Shane,
      I think you bring up a good point in whether or not engineers understand the consequences of their actions. Even as a student, especially in this course, I think about how my future designs will impact those around me. The issue with the lack of motivation of the project team because of profits is that this seriously goes against the code of ethics. The profit the project team may or may not make should have no effect on the design professional’s attitude towards making the building as safe as possible.
      This reminds me of a discussion the engineers were having during my internship about the amount of detail they put into their submissions. Even though they were confident in the contractor’s knowledge of their practice, they communicated more than enough detail for the design to be build safely and effectively.
      As for the lack of knowledge, do you think this also goes against the code of ethics? Or even the requirements for the PE license, in that engineers should have an aptitude or competence in their field of study? Is it too extreme to say that the engineer should have known about these specific design considerations, despite them not being explicitly mentioned in the codes at the time? I think for the case of the Save-On-Foods, a peer review of the designs should have been conducted before construction which could have reduced the causes of failure.

      • ErikS
        September 7, 2016 at 3:43 pm #

        Following up with your comments here, Shane and Rebecca, I believe the Code of Ethics does get set aside sometimes when it comes to engineering judgement, especially when it comes to cost savings and or keeping clients “happy”. When an engineer, private or government, is pressed to get work done and they may skip some steps to move the project along more efficiently. This may also include either handing the work off to a less qualified engineer or doing the work him/herself even if that may not be their area of expertise (as you have both mentioned). The engineer may be more familiar with concrete design but be pressured into steel design and have similar issues as discussed in the articles. A more extreme, but actual problem, is a mechanical or electrical engineer may be asked to do structural work (or vice versa) when budgets do not allow for hiring or subcontracting a more qualified engineer to do the work. Thank goodness this is not the norm but it does happen. If you get a request to design something you are unfamiliar with look things up to get a sense of what is necessary but also be willing/able to ask for assistance. Also, make sure a qualified senior engineer reviews your work. This does not come from personal experience on the design side but I have been asked to peer review or assess structures that were not designed/reviewed properly.
        Per the engineering code of ethics, engineers are only to perform services in their area of competence. You may be on the opposing side of an engineer who did not heed the code of ethics.

  9. Joshua Z
    August 31, 2016 at 6:30 pm #

    One thing that I noticed in the “Lessons Learned” part of the Skyline Plaza collapse was that the first lesson said, “Redundancy in structural engineering is essential to prevent progressive collapse.” During class, we also discussed a truss bridge that collapsed immediately after a truck struck one of its members because it was essential to the integrity of the structure. Additionally, we talked about the balcony at the University of Virginia that had no redundancy and collapsed immediately once it was put under too much load, which lead to the death of a student. The balcony was built during the time of Thomas Jefferson, so I don’t feel that I can criticize him for the lack of the use of factors of safety. However, the truss bridge (I believe it was the I-5 Mount Vernon Roadway crossing the Washington Skagit River) collapsed in 2013. I understand that the bridge was not built then, but I’m assuming that the bridge had to be inspected periodically in order to insure that it was safe for yes. In that case, wouldn’t it make sense to ensure that the structure had enough redundancy? The same goes for during the design of the Skyline Plaza building. I mentioned negligence in my previous post, and it again seems to be a theme in this building as well.

    • Yamile R
      August 31, 2016 at 10:40 pm #

      Joshua:
      I agree with you on the idea of redundancy being essential for structural design. As you mentioned, the I-5 Skagit River Bridge, collapsed due to damage caused by an oversize truck traveling in the wrong lane. The structural system selected with non-redundant load-bearing beams and joints, crucial to the whole structure staying intact, and not considering the possibility of collision of one of the members.

      • mkev
        September 7, 2016 at 10:46 pm #

        We Don’t Build Them Like We Used To…and maybe that is a good thing sometimes!

    • Alec B
      September 6, 2016 at 10:46 pm #

      Josh,

      As far as a redundant design is concerned, I’d imagine that redundancy is often misunderstood because more complex models and analysis/design must take place to ensure redundancy. Perhaps more “routine” structures are designed too closely based on experience designers have in designing similar structures “that have always worked.” Jumping to conclusions/solutions too quickly during design may result in engineers overlooking certain unique features of the structure/design – this may be why redundancy in design is sometimes overlooked in parts.

  10. Prateek Srivastava
    August 31, 2016 at 10:54 am #

    Post 1: Commentary:

    “To err is human”, going by this line, humans are meant to make errors/mistakes but in my opinion not at the expense of people’s life, property etc.
    Most of the failure cases as discussed have been due to negligence of people and lack of knowledge. As civil engineering projects are of humoungous stature involving many people,its like a tower of cards, if any card fails to prove its utility the tower falls down likewise for a civil engineering project if any person fails to fulfill his/her duty, the building is not going to eventually serve its term of serviceability for which its designed for.

    Parking Garage San Antonio:

    As i read the article, one of the main reasons found for this failure was lack of grout in all the column connections present. Despite the fact, as the forensic team found that CEG mentioned clearly that about the grout requirements there were no evidence of grout being installed at the column connections.
    Whether it was done to save on budget or it was simply overlooked, thats a question to be answered.

    Other than improper grout installation there were issues causing reduction in joint moment capacity, there were enlarged holes in base plates, pier extensions were lacking confinement ties etc.

    Similar failure case happened at Fishers Parking place garage as well where lack of grout in column to pier connection led to structure failure.

    Rana Plaza, Dhaka Bangladesh:
    One of the deadliest building failures in Bangladesh which killed over a 1000 people, has many reasons which led to its failure. Being a developing country comes with lots of challenges, like to cater ever growing population, to minimize illiteracy rate, to provide for basic necessities to their countrymen.

    The reasons of failure being,

    Here, again comes negligence or lack of forsightedness with the attitude to ‘build for present, don’t care about future’ attitude. i don’t know whether the soil investigations were made prior to construction or not.
    The building was constructed over a swamp where the soil strength was inadequate to hold the weight of the building. Instead of replacing the weak soil with a better strength layer of soil, trash was used to fill in the swamp.

    Second reason being the building was imposed on loads which were not within the design criteria. The design was in support of just four storeys primarily for commercial purposes but later four more storeys were added totalling it to 8 floors and 9th in construction at the time of collapse.
    I am appalled by the fact that how people can take things for granted which involves loss of lives.

    Third reason found was usage of inadequate quality of materials. The building codes were rarely enforced in designing this building.

    Bottomline, my question being,

    How can people be so negligent or knowledge deprived and can take things for granted irrespective of the location in the world.

  11. Mehrzad
    August 30, 2016 at 8:48 am #

    Reading the articles and the three case studies, I believe the most important factor to reduce the risk of building failures is for owners/superintendent, design teams and general and sub- contractors to do their utmost diligence for the segments that they are responsible for. It certainly is a difficult aspect as the timing and cost constraints for such parties play major restrictive/discouraging roles that may lead to construct unsafe/non-performing structures within a reasonable life expectancy.

    The case studies accentuate the importance of management and understandings: It is a good measure for owners to have understanding of the cost and time requirement while taking necessary steps to keep records of contract and maintenance documents for future unpredicted modification to the structure. Design teams must have a comprehensive feeling for their design/analysis implications while not shying away from including a necessary number of site surveys in the proposals to bring them to the same page of the actual site situation. Contractors, as the major monetary beneficiaries of total construction cost of a project, must comply with all their requirements and be mandated to be certified by code and educational entities.

    I had a site visit at a Save-A-Lot store with Butler prefabricated steel frame similar to the Save-On-Foods case study with cantilever framing. Due to the lack of management and communication at the construction time, the drawings that the owner provided me with, being regular wide-flange steel framing, were not reflective of the actual steel framing on site. It turned out that at some point, for the cost reduction purpose, the owner decided to go with the prefabricated framing.

    The store needed several new heavy rooftop units that having no access to the actual drawings could complicate the analysis and increase the likelihood of errors as there would not have been much information on the steel grade and the design rationale.

    • mkev
      August 30, 2016 at 10:34 pm #

      Mehrzad,
      I had a similar experience as the engineer of record on a project. The developer changed the conventional steel design of a shopping center with a stepped roof to a metal building. The metal building engineer failed to take into account snow drift at the roof steps (aka our discussion in class last time) and the roof collapsed. It is a long story with several other lessons. Somebody ask me about this in class some day especially when we discuss snow collapses or legal issues.

  12. Shubham
    August 30, 2016 at 3:59 am #

    1) Save on Foods, Station Square

    Comment:
    “Throughout the design process, a number of revisions were made, during which the beam was reduced in size.” — I believe the revisions were made only from local perspective, and to cut down cost.
    Cutting down the cost is common during reviewing the shop drawings, and I agree you can save a significant percentage of material/ cost, but more importantly the global impact of this change should be promptly assessed to ensure safety.

    Secondly, so much of calculation errors on the part of Structural Engineers. That’s sheer negligence and unprofessional practice, by the PE who signed the shop drawings.

    Question:
    Could MKev tell us about ‘how Gerber system is economical’ and ‘buckling/ distorsional failure” in class? The buckling failure might be helpful as a quick revision to all of us.

    2) Skyline Plaza

    Comment:
    I am intrigued by the breakdown of three cases to analyze the failure, because they relate all the possibilities to the material strength.

    Question:
    “Even though the contractor did not comply with the shoring requirements specified in the construction documents, the collapse was still found to be the fault of the designers.”
    I think the contractor wanted to expedite the construction and/ or needed those shoring from lower floors to support upper floor construction.
    Why the designers were responsible in this case?

    Another example:
    Kolkata bridge collapse – 31 March 2016
    I am not aware of any report of the investigation for this failure.
    Some of the causes that I guess maybe, substandard building materials, poor site supervision, also improper training of workers.
    Will post more solid information, as I learn anything.

    • Yamile R
      September 7, 2016 at 6:39 pm #

      Shubham:
      About the Gerber system, “When designed correctly this system can provide a more economical design due to reduction in steel section sizes, allowed because of lower stresses induced in the beams (Essa et. al. 1995, pp.1667).”

      According to the article, the conclusion of the Skyline Plaza case was that designers and architects were found guilty since it is their responsibility to inspect the job site and pay a number of visits. They must fulfill this in order to prevent and warn for any mistakes from the contractor or discrepancy with original design and drawings.
      Again, the industry response about this is “This accident also made designers aware of the importance of site inspections and that it is still the responsibility of the designer to make sure the building is constructed properly.”

  13. Rebecca M
    August 30, 2016 at 12:06 am #

    Before considering the building failures cases, it didn’t occur to me how often forensic investigations are needed due to miscommunication and some sort of negligence during construction. After reading the Architectural Record references it’s clear that the majority of building failures are not exactly “dramatic” collapses, instead caused by issues that could have been avoided.

    However, as shown in the Bailey’s Crossroads case, a devastating collapse did occur due to the removal of slab forms too soon during the placement of other floor slabs. After running three separate cases to analyze this failure, it was illustrated that the shear stress of certain columns were too great for the capacity of the slab. After further reading, inspections before, during, and after concrete placement were required but not completed. This non-compliance issue has lead me to wonder why site evaluations from OSHA officials weren’t conducted. Also, after listing all other non-compliance issues, how do you ascertain which others additively aided in the progressive collapse of Skyline Plaza.

    • Alec B
      August 30, 2016 at 12:28 pm #

      Becca,

      I found the Bailey’s Crossroads Failure quite interesting because investigators asked witnesses/workers-on-site what occurred. Investigators were provided with three different accounts of the collapse which helped to form the three separate cases to analyze in order to help determine the cause of failure. The Bailey’s Crossroads investigation is a great example of how investigators use the accounts of witnesses to help formulate the process of their investigation. However, some sudden building failures (like collapses or partial collapses) that occur during construction sometimes happen overnight when no workers are present (fortunately for the safety of the construction workers and design professionals that would be on-site). How do you think investigations are started when one can’t begin asking witnesses for their personal accounts? (I’m thinking of the Washington D.C. Convention Center where the roof trusses fell on each other like dominos in the middle of the night.)

      • Rebecca M
        September 7, 2016 at 9:36 pm #

        Alec,
        It seems as though your question was asked at just the right moment, as discussion on the very topic has been brought up concerning similar situations. It seems to me that these site investigations, of collapses without witnesses to attest, could be slightly easier to analyze, owing to the fact that the scene wasn’t as disturbed as it could have been with the presence of witnesses or need of first responders. I would assume that thorough documentation of the site would be the very first step in beginning such an investigation because there is the potential of unearthing evidence of some sort of deficiency or deviation in the building material. In the case of a collapse without witnesses, a point of inspection also could be identifying the condition of the structure when it was last occupied, as in whether or not it already had shown signs of poor condition. Hopefully, the next few weeks will provide more ideas of what to think about when beginning a building failure investigation.

  14. Di W
    August 29, 2016 at 11:57 pm #

    All three cases have been reviewed.

    The imperfection in related laws is the most significant defect from my perspective in reading the articles. As are shown in the “supermarket roof collapse” article, engineers made mistakes that were easily avoidable such as calculation mistakes and drawing mistakes. No one could find those mistakes during the design progress and construction progress. A stronger supervision system is needed and a series of much more strict law is expected, meanwhile, which could verify the responsibilities if failure happens.

    After reading or hearing so many building failure cases, we can see that most of the building failures are associated with building materials and are the consequences of wrong or inappropriate design and construction. Unpredictable severe damages are always caused by using wrong size, shape, strength or the choice of material. In the supermarket roof design, the engineers chose a smaller size beam and a thicker slab. The thicker slab increased the self weight and the smaller size beam decreased the ability of buckling resistance. However, I guess the construction engineers might have found the flaws of the design but did not argue for it for some reason. The inappropriate design in cantilevers were obvious. The article also mentioned the competitive biding and I guess money might be another important reason that the engineers changed the beams and slabs.

    As far I still believe age is the main reason that causes failure. As too much reliance is given such as IBC or ACI etc., Man-made failures should be few even though the codes are not perfect and needed to be updated. I did a site investment of PennDOT bridge #27 located in Bellefonte when I was in another course last semester. The bridge has been used for over 90 years and there are only several corrosion at the bottom of the bridge caused by alkali silica reactions.

    • mkev
      August 30, 2016 at 10:26 pm #

      So, I will kick in here with the voice of experience for all of you to consider. Did the engineers really select a smaller beam? Would you swear to that in court? All you really can say is that a smaller beam showed up on the final drawings if I recall correctly. What if a draftsman copied the size wrong from a markup up print with sloppy lettering etc? In forensics, don’t assume anything.

      • Alec B
        September 6, 2016 at 10:31 pm #

        This is a very interesting perspective that I didn’t initially consider. This perspective reminds me of an experience I had this summer during my internship. I was tasked with finding any additional capacity of a steel beam that was to be subjected to additional weight of hospital equipment. Site photos with measurements of the beam led me to believe with enough confidence that the existing beam was a certain W-shape. Upon analyzing the beam for the additional load, I checked my work with a senior engineer. He approved of my thought process on determining the beam size, but he questioned if it could be a slightly smaller W-shape with similar dimensions. To be absolutely safe, I ran the analysis once more just in case the field measurements were slightly off. This just proves that whenever extra steps may be taken to gain more confidence and ensure one’s analysis/design, they should be taken to help reduce risk.

  15. Yingzhe You
    August 29, 2016 at 11:57 pm #

    After reading three materials and comments below, I still have some thoughts.

    For the supermarket case, one of the reasons that lead to undersize of the beam is incorrect DL. Since all designs have to meet the code, that’s to say, they may be good to stand even if the load is a little bit higher than the assumption. However, 55% is not a small number. Since I have no experience in working in the construction site, I’m wondering is it common to make slightly change the size or material during the construction without telling the designing company? Efficient and convenient ways of communication should be set up between contractor and designers.

  16. philr
    August 29, 2016 at 10:27 pm #

    Found the analysis to answer my previous question. here is the original full report for the Skyline Plaza Collapse.

    http://www.nist.gov/customcf/get_pdf.cfm?pub_id=908891

    • mkev
      August 30, 2016 at 10:22 pm #

      Nice work Phil! You all should look at the fine details of this report.

  17. Yemi O
    August 29, 2016 at 10:00 pm #

    Reading through these articles really emphasizes the importance of bodies responsible for safety and health during the construction of buildings. It is quite interesting to see that the failure to “inspect before, during and after the placement of concrete” as seen in the Skyline Plaza can contribute significantly to its collapse.

    To digress a little, I am from Lagos, Nigeria, where construction is done very frequently and through my experience interning there in comparison to here, I find a lot of flaws in the system especially with regards to having a governing body such as OSHA. Often times, if a collapse does happen, the structural engineers immediately take the blame whereas that may not be the case.

    I wonder if there are cases where major discrepancies in the code may have led to significant collapses or failures. Furthermore, can an argument be brought saying agencies like OSHA should take extra steps in ensuring safety? I am not entirely familiar with how the process is done but I assume these governing bodies are called upon by the general contractors.

    • mkev
      August 29, 2016 at 10:24 pm #

      Yemi,
      We will spend a fair amount of time in class discussing the various codes and regulatory organizations. OSHA is a government agency set up to protect construction workers of various types among various other mandates. There is a link to the OSHA site on this page and any of the main Building Failures Forum posts or get there direct by using: https://www.osha.gov/doc/index.html

      In particular you will hear a lot about OSHA on the job site during the erection / construction of the building.

  18. Alec B
    August 29, 2016 at 9:52 pm #

    As we learned from the reference articles, case studies, and lecture notes, a building performance failure is not often a single cause but rather rather several factors which negatively affect the performance of the building. Many of these factors have a direct impact on other factors until ultimately one factor is “the straw that broke the camel’s back.” Despite the advancements the building industry has made in the past several decades, mistakes still occur and go undetected in the design and/or construction of buildings. When failures happen, the integrity of the building is compromised and oftentimes the entire building’s design and construction are open to a thorough investigation. Such investigations may lead to the discovery of additional, non-contributing errors in the design and/or construction which only further dismantles the integrity of the building, the contractors, and the design professionals. Take, for instance, the collapse of Skyline Plaza: the main factor which led to the collapse was the actual strength of the concrete slab of a particular floor not meeting the design strength of the slab at the time of the collapse. In the investigation of the collapse, numerous OSHA infractions were also discovered that were not believed to have directly impacted the building failure. However, the infractions were still indicative of how the construction of Skyline Plaza was performed and managed which may be considered to have indirectly affected the building failure. A building failure has the ability to expose a multitude of problems with the design/construction of a building that may have forever gone undetected if not for the building failure in the first place.

    Assuming a building failure is not completely destructive, there is an interesting dilemma that is introduced when attempting to find the right balance between the cost of the solution and the effectiveness of the solution. According to some of the case studies and building failures examples, it seems there is a tendency for owners/contractors to select the cheaper solution which may end up being a bigger problem in the long-run with even more cost associated with the future problem(s). Granted, some owners/contractors seem to select the most effective solution despite its impact on cost. It must have been extremely difficult for the owner/contractor to replace all marble panels of the Amoco Tower (which equated to a cost of replacement of about one-half the original cost of the total structure). However, the problem was correctly solved and there were no more ongoing worries about the performance of the building’s cladding.

    During my summer internship, I performed a few site surveys at parking garages in need of rehabilitation work. The one pre-cast concrete parking garage was surveyed over a decade ago by the company I worked for during the summer. My company drew-up the repair drawings for the owner/contractor, but ultimately the owner deemed the repairs too costly. Instead, the owner paid thousands of dollars nearly every year to temporarily fix the damaged areas of the parking garage. After years and years of temporary fixes, the owner re-contacted my company to perform a new site survey and draw up new repair documents. Though the owner is finally repairing the garage as it should have been repaired in the first place, the owner wasted tens of thousands of dollars on temporary repairs that need further repair anyhow – not to mention many potential customers were likely driven away over the years by a parking garage that appeared unsafe. I understand it must be difficult for an owner/contractor to weigh out the cost and effectiveness of a solution, but perhaps the longevity and sustainability of a building should be prioritized higher than it is for most owners/contractors/design professionals.

    If owners, contractors, architects, and design professionals begin thinking of the building’s outcome of design/construction rather than focusing on the building’s output of design/construction, perhaps some building failures may be prevented. Sure, some errors are more difficult to prevent than others – but the majority of building failures may be easily prevented with careful thinking and learning from the mistakes of others.

    • mkev
      August 30, 2016 at 10:20 pm #

      Unfortunately, Alex, your experience is not an isolated one. We see this a lot. The forensic firms have a term for it….job security…

    • MichaelB
      August 31, 2016 at 3:56 pm #

      Alec

      I also helped inspect some concrete parking garages (cast in place slabs and columns instead of precast) this past summer. Like you I was surprised to learn that the solution to repair these cast in place garages seems more like a quick fix then a long term solution. We would basically find spots in the top of the slab and soffit by chain dragging where there was cracking or where concrete was literally separated at the reinforcement because of water penetration to the rebar. We would mark these areas so they could go back and cut out a layer of the slab, clean the rebar, and repour the concrete.

      It was also interesting to see that the reinforcement in these garages were clearly not placed with enough clear cover as ACI requires today. Some of the concrete that was falling off exposed rebar that clearly had even less than a 3/4″ of cover. This definitely contributed to the concrete failing as garages especially susceptible to moisture infiltration with the salts that cars bring into the garage.

      • Alec B
        September 6, 2016 at 10:18 pm #

        Michael,

        Your site surveying seems fairly similar to my experience. I, too, performed chain dragging to help expose any problem spots in the concrete. You mentioned issues with clear cover and exposed rebar. In our area, road salt is a concern for parking garage designers to consider. It makes one consider where engineering judgement comes in to perhaps increase clear cover for some concrete parking garages exposed to road salt in a climate that sees a lot of ice/snow in effort to reduce the spalling and delamination of concrete.

        • MichaelB
          September 7, 2016 at 9:17 pm #

          Alec,

          I agree, as Parfitt mentioned during class it is up to the engineers to consider as possible scenarios that a building may face. If the owner is willing, increasing the slab thickness to provide more cover could be worth it in the long run for parking garages if it can help prevent issues later on.

          I also remember hearing stories about contractors refusing to seat rebar probably because they insisted they could get the job done faster by just holding the rebar up while the concrete was being poured. Obviously this is not a good way to get cover as it is not accurate and the rebar could easily settle down and reduce its cover below what was called for. This could reason for some of the non existent cover in older parking garages.

          This just further emphasizes the importance of ensuring that everything is in sync between designers and contractors.

  19. Ishan Uppal
    August 29, 2016 at 7:03 pm #

    A few points that I found interesting/worrisome,

    1. Supermarket Roof Collapse.
    a. The Structural Engineer made many incorrect assumptions (wrong yield strength of steel), calculation errors (actual DL 55% higher than design DL). However, during construction, extra concrete was placed on deck. Also, a walkway was widened using concrete instead of foam-type insulation, as specified in the drawings. This begs the question, does the blame really, primarily, lie with the Design Engineer? I think the Contractor is equally unprofessional.
    b. The beam size was reduced from a W24x104 to a W24x76. The inquiry could not ascertain the reason for this. I wonder how bad the communication in this Structural firm was. Wasn’t there any peer-review within the firm when such a reduction in beam size was suggested? Gross miscommunication.

    2. Parking Garage Collapse in San Antonio
    a. When Walter P Moore and Associates conducted forensic investigation, they collected samples from the rubble, amongst many other things. I wonder how these destroyed samples would have been useful? Any answer anybody?
    b. The shop drawings produced by CEG wrote clearly about the requirements of the grout installation beneath the column base plate as well as all column to pier and column to column connections. Yet the investigation found no evidence to show such that such critical measures were taken. The fact that such a major step in construction was overlooked on a construction site (that was being developed in 2011!!!) makes me wonder if corners were being cut to save money. How did no Site supervisor/Engineer raise questions?
    c. A very similiar mishap took place in 2002 at the Fishers Place parking garage, where the reason of collapse was lack of grout in the column to pier connection. The industry should have placed regulations to ensure that grouting operations are not overlooked. The fact that this issue has yet not been addressed by OSHA to date is reckless and irresponsible.

    • ErikS
      August 29, 2016 at 9:56 pm #

      Ishan, depending on the size of the samples collected they may contain steel reinforcing that may show signs of failure (fracture, shear, tension) or other defects, including incorrect steel strength. This sample may also show a lack of or too little steel. It may show the concrete was a pour mix (air, water/cement ratio) or was not meeting the strength requirements. If the samples are big enough they can destructively test them or they can use them for petrographic or chemical analysis. It is surprising what a good investigative lab can do with “relatively” little. They should hopefully have mapped out the debris field before the site was cleared to map out how the structure collapsed. What is where and what was on top of something else helps provide a timeline of how things fell (think Pick-Up-Sticks). This is what you will should likely hear about with Fisher Place as I assisted with that collapse investigation (briefly).

    • Alec B
      August 30, 2016 at 12:49 pm #

      Ishan,

      You mentioned in your post placing blame in the event of a building failure as well as how miscommunication can be the root of severe building failures. Structural engineers note important information for the contractors on the structural drawings that directly impact the performance of the design based on how the structural element was designed in the first place (an example may be noting the sequence of back-filling a retaining wall if the retaining wall is designed for certain active/passive pressures that rely on the proper sequencing of backfill). It is sometimes the mentality of structural engineers that their job is done after putting this information on the drawings; after all, they did “protect their designs” and “shed blame” on the contractors in the event that something were to go wrong. Perhaps structural engineers can be more vocal with the contractors and call more attention to critical notes during meetings or reviews. I understand it is the role of the contractor to pick-up on all notes on drawings, but I understand how some things may be overlooked considering the scale of some projects.

      • Mehrzad
        August 30, 2016 at 3:19 pm #

        Alec / Ishan,

        Talking from my little experience, there are also communication channels through which the most efficient project-specific solutions are set up. While as an engineer it sometimes is appropriate/accepted to have direct contacts with contractors, some architects, in order to take more leadership roles and to avoid unpleasant consequences, and to appeal to owners for prospective projects, want their design consultants not to signal information directly to the contractors or owners. There is still a learning curve for me and I think a welcoming view is required by design professionals to adjust to various circumstances and to have more smooth communications.

        It is true that critical job procedures, if not noted and detailed well on the contract documents, will eventually come back to the design teams in shop drawings or in later stages in case contractors are careful and responsible. This does not exempt the design professionals of attention to all facets when generating contract documents. Together with possible non-performing engineering liabilities, shortage of proper information by the design team may encourage some contractors to ask for additional change-order fees for unforseen and/or made-up scenarios that might later consume resources of the designers to further investigate the site situation or later on, complicate steps required to probe the structure for possible post-failure cases.

        Using information modelling computer programs and timely circulation and coordination of the produced files between the involved entities can significantly mitigate discrepancies in more involved modern-day projects.

    • philr
      August 30, 2016 at 8:36 pm #

      I agree with Ishan’s comments on both examples.

      One additional point is that the Supermarket had multiple errors by multiple parties (assuming that the extra concrete was a unilateral decision by the contractor and not coordinated with the design engineer), any one of which could realistically be blamed for the failure.

      On the other hand, while other deficiencies were noted, the San Antonio failure was a result of a single process oversight..the grouting of the column connections – which means the construction process appears to have a single point of failure. While the importance of the grout was recognized by the detailer in the notes, the erection process, like a proper design, should have redundancies built in. While there was temporary bracing on the structure, it obviously was not designed in consideration of a failure of this magnitude. I will note that a check of IBC 2015 table 1705.3 (special inspections for concrete) does not mention grouting at all. That table also references ACI318 chapter 26 (sec 13.3.3) which simply states “Sequence of erection of precast members [shall require periodic inspection]”. Nothing beyond that. The only time grouting is mentioned with respect to inspections is when reinforcement (typically post tension) is grouted after installation.

      • mkev
        August 30, 2016 at 10:17 pm #

        Would you all believe me if I told you the following is all it says in OHSA requirements for Precast Construction???

        1926.704(a)

        Precast concrete wall units, structural framing, and tilt-up wall panels shall be adequately supported to prevent overturning and to prevent collapse until permanent connections are completed.

        1926.704(b)

        Lifting inserts which are embedded or otherwise attached to tilt-up precast concrete members shall be capable of supporting at least two times the maximum intended load applied or transmitted to them.

        1926.704(c)

        Lifting inserts which are embedded or otherwise attached to precast concrete members, other than the tilt-up members, shall be capable of supporting at least four times the maximum intended load applied or transmitted to them.

        1926.704(d)

        Lifting hardware shall be capable of supporting at least five times the maximum intended load applied transmitted to the lifting hardware.

        1926.704(e)

        No employee shall be permitted under precast concrete members being lifted or tilted into position except those employees required for the erection of those members.

        [FR 41088, Oct. 5, 1989]

        Ask Bill Moyer of Davis about it when he comes to class!

  20. ErikS
    August 29, 2016 at 5:54 pm #

    While not as glamorous as true “forensic investigations”, building assessments coupled with regular maintenance are critically important to maintaining a safe, efficient, durable building. Owners do not always recognize the impending failures they have on their hands when they observe a “simple” water leak around a window or masonry cracks within their facade. These signs are often telltales of deeper hidden problems developing. For example uncontrolled water penetration within the walls can lead to corrosion of structural elements that could cause gypsum wall board (drywall) to crack, walls to buckle, masonry units to crack or fall, or structural members to have section loss great enough to weaken the structure, facade, or roof.
    Corrosion of a steel support member, such as the lintel supporting the brick header at the Williamsburgh Saving Bank in Brooklyn, New York, can lead to catastrophic injuries or worse if the “cracked and broken” brick units had not been observed and removed. The building assessment work performed identified this deficiency and remedied it before further damage could occur.
    Similarly with the marble cladding at the former Amoco Building in Chicago, IL, a building assessment discovered the cracking marble, which eventually led to an expensive full-scale facade replacement but no one was injured or killed and no damage to property occurred due to failure of a panel due to early discover of the issues.
    Building assessments cost the Owners money; however, as PhilR alluded to in his post and Kevin has stated numerous times during the first two classes, the $1, $10, $100 rule is accurate. Finding and remediating the failure early on will have savings magnitudes greater than repairs later when the failures are more extensive or subsequent repairs are required.
    The facade ordinances are extremely important in big cities as these buildings are generally tall and difficult to access and owners would rather say they do not have issues and do not want to pay someone to tell them the same; however, time and time again you will read about building facades that have been standing for quite some time quietly deteriorating until a tragic failure occurs.
    Owner education as to the importance of properly maintaining their buildings and facilities is paramount.

    • mkev
      August 29, 2016 at 10:16 pm #

      Excellent points Erik. Statistics are hard to come by as you know but I don’t think there is any question that in the big picture, facade damage, maintenance and repair costs far exceed that of full or partial collapses.

      And for those who think the Amoco building was a one off problem, see this article on the failures wiki for several more examples of thin stone facade problems.

      https://failures.wikispaces.com/Thin+Stone+Facade+Problems+and+Causes+of+Failure

  21. Joshua Z
    August 29, 2016 at 5:29 pm #

    In reading through the articles, there were a couple of things that I found interesting, specifically in looking at the case of the collapse of the roof in British Columbia.

    I was particularly intrigued by the second mode of failure, the buckling of the beam that occurred as a result of the lack of buckling resistance. It is mind boggling to think that nobody at the structural engineering firm considered this mode in their calculations. Not only was there no original design for this, but nobody caught this upon reviewing the design, if there was any. Additionally, even if there were “improved restraint details,” as the article notes, the beam still “would have been inadequate to support the factored load.” So, for me, this begs the question, how much buckling resistance would need to be added to prevent this from happening, if it was possible?

    I also noticed that one of the beams was noticeably undersized. I was wondering if the beam was sized as a W24x104 instead of a W24x76 like it was, how much slower would the beam fail? And how would that impact the failure of the beam in buckling?

    It appears that the failure of this structure was primarily centered around negligence on the hands of the structural engineer and the contractor, and the mistakes that were made could have been easily prevented.

  22. MichaelB
    August 29, 2016 at 12:05 am #

    In reviewing the Skyline Plaza Collapse case, I found the conclusion for responsibility interesting. As far I understand from the wiki the structural engineer did not make any visits to the job site. I am curious whether the contract to the owner for the structural engineer specified any site visits.

    If site visits were stipulated in the contract, it was especially negligent of the design engineers to not go on site at any point during construction as they could have easily avoided the collapse (Although the early removal of shoring was inexcusable either way).

    • mkev
      August 29, 2016 at 8:53 am #

      Michael,
      A good question and one that is worth digging into a little more for this particular case. As I may have mentioned in class, in reviewing these historical cases, we need to put ourselves in the time frame of the original case. I can tell you from experience that around the time of that collapse, it was the school of thought by many companies and their professional liability insurance carriers to encourage engineers NOT to take on site inspection duties. The thinking was that if you did not see the problem or if no one could say you should have seen the problem when you were on site then your firm would not be liable. That of course was false and wishful thinking. Today the trend is to try to monitor the jobs because anything you catch causes less liability.

      That said, many owners did not want to pay the design professionals for additional time or services so it could have been either way. Worth checking into either way.

      This was also one of those cases that had multiple problems and process failures. I encourage other students to comment and discuss what the events were that resulted in the early removal…in other words, the root cause, not the trigger mechanism.

      • Brendan B
        August 29, 2016 at 11:18 pm #

        I was also interested in the skyline plaza study as it made me realize the importance of knowing what you are legally responsible for.

        That being said, shouldn’t the contractor hold more liability since the shoring requirements were specified in the CD’s? Wouldn’t the general contractor’s contract state their responsibility to follow the CD’s? Also would the engineer still be liable if the contractor made a mistake after the engineer visited the site (since they technically did visit the site)?

        This certainly could have been prevented if the engineer performed a site visit and provided more detailed instructions on formwork removal. However I still question why the contractor gets off the hook. The legal side of building failures is definitely something I am looking forward to learning more about in this course.

        • Joe H
          August 29, 2016 at 11:56 pm #

          Not only is the legal side a big issue and controversy, but the moral side as well. I was particularly held up on a quote by David Odom in the first article regarding routine maintenance issues. As we discussed in class these are by definition failures, but one pays them attention as that, and the same firms make the mistakes again and again. While these are not catastophic mistakes by any means, they are still fixable problems that are overlooked. Perhaps the design or construction firm feels they made no mistakes. Perhaps they don’t want to take the chance of finding a mistake. Either way, it is a hindrance to the success of the building and future buildings. It is no fun to find out you messed up, but understanding mistakes from the start can help prevent them in the future, and a company that goes out of their way to do this is going above the established normal standard.

          This moral obligation should honestly overpower the legal obligation. Even if the contract doesn’t explicitly state to follow the CD’s or inspect certain elements, I feel that it should be understood and routine. Perhaps I am being naive from a lack of experience in the construction industry. But I do remember in our EDSGN130 class, we were doing a CAD assignment and were told that for the assignment, we didn’t need to draw some siding behind a railing. However, it was explained to us that if the actual drawings had not shown siding, the contractor would not be responsible, even if 90% of the wall had this siding and it was very obvious that it should be 100% of the wall. I guess thats why they have RFI’s and change orders for things like that, but the moral vs legal obligation is a very touchy and most likely reoccurring theme throughout the course

          • mkev
            August 30, 2016 at 10:05 pm #

            Good example, Joe. In reality we would look at the specification, the general notes and the drawings / details. You would likely have a different outcome on the non-shown siding if there was a good team relationship with the contractor, perhaps a different one in discussions on extras and possibly a third version if the claim went to court. You example is why you often see a lot of very general cover you back notes such as siding shown is representative of general conditions etc.”

        • mkev
          August 30, 2016 at 10:08 pm #

          Did anyone actually look up what the requirement was for removal of the shoring and going to reshoring? Do we still do it that way today? Are various specifications used to determine removal of shoring? Dig deeper everyone!

          • philr
            August 30, 2016 at 11:16 pm #

            ACI 347 gives good info when it comes to shoring, especially section 3.7.2.3 in the 2014 edition.

    • philr
      August 29, 2016 at 9:28 pm #

      On the Skyline Plaza case, it was not stated specifically as to how CBT (the forensic organization) came up with the 1200 psi (Case 1) and 1340 psi (Case 3) concrete strength assumptions. Were any compression tests completed on similar mixtures from the same plant, under similar temperature and humidity conditions…or were these strengths simply estimated?

  23. philr
    August 26, 2016 at 4:40 pm #

    Two points:

    When I was on the board of my high-rise condo homeowners association, we had a difficult time convincing the owners (and renters) that the top level of the three year old (and in almost-new condition) underground parking garage had to be vacated for three weeks so a slab membrane could be put down, not to mention the $200K price tag. We stated that this project would prevent what could be several months of repairs in 15 years, and prevent what happened in this article. The board approved the project over the voices of a few non-resident “investor” owners.

    It was apparent that the opposing “investor” owners did not expect to own the property in 15 years, and did not want to contribute to something they would not necessarily see a benefit from (even though the money for the work was already in the building’s budget and a special assessment was not needed.) Fortunately, the HOA board consisted of long term owner / occupants who planned to be there for a while, plus a investor who happened to be a registered Structural Engineer (not me).

    So my first point is here that a lot can be learned about how a building has been maintained by evaluating who has owned it. Is it the long time headquarters for a high visibility professional corporation? The there is a better chance it has been pretty well taken care of. Or has the building been a market-timed real estate flip for a series of investment groups? If that is the case, then the a bit more digging into the real condition of the building is likely prudent.

    Which leads me to a second point. I would be curious to know if the owner of the parking garage in the example was the original owner. Maintenance records and blueprints do not HAVE to be conveyed when buildings are sold. The original owner may have taken meticulous care of his prize building, but that care may have disappeared with the next owner, along with many of the blueprints and maintenance notes, leaving the next owner (or investor) to start over with much less to work from.

    • mkev
      August 28, 2016 at 11:21 am #

      Phil,
      Excellent points all around and well thought out. You can tell a lot from the practices and goals of the owner. And, from experience those with a long term outlook often have retained the plans, maintenance records, roof warranties, etc. that can make a facilities condition assessment that much easier.

      From a similar perspective, those owners and developers who plan to flip the property soon may also chose lower FIRST cost mechanical systems. They are not concerned about the energy bill (all electric individually metered to each tenant for example ) rather than think about spending a little more first cost to gain life cycle cost and operational advantages with a central system. Attitudes are changing a little with energy because energy hog buildings are getting harder to rent and flip.

      Those of you living in some of the older / large downtown apartment complexes may have some first hand stories concerning this topic. Any examples?

      • Joe H
        September 5, 2016 at 10:38 pm #

        I think the state college apartment market is very interesting for this sort of repair because the turnover window is so short between tenants, ususally about 3 weeks, so major repairs are very difficult logistically.

        3 years ago I lived at Lenwood Place (917 S Allen St). There is a 1 story elevated parking level between my building and the one next to it, and while I lived there it was noticeably damaged and had a lot of the deflection. After I lived there they began repair work on the structure. This repair cost them about 30-40 parking spots. I don’t know the exact time frame of the repair because I wasn’t able to track it being so far away, but it was definitely a big financial burden with the price of parking spots downtown.

        • mkev
          September 5, 2016 at 10:58 pm #

          Glad you waited for the repairs to park there. This could have been you!
          http://www.pressconnects.com/story/news/local/watchdog/2015/09/10/parking-ramps-safety/72029112/

        • mkev
          September 7, 2016 at 9:08 pm #

          Joe,
          I am pretty sure I know the garage you are talking about. I looked at it “unofficially” after the Peppermill garage collapse. Perhaps it eventually couldn’t meet the requirements of the Centre Region Property Maintenance Code. The section on parking garage inspections was passed after the Peppermill failed. So, this is perhaps a successful result of a code change from a failure that has built some institutional memory into our system. See below for wording:

          302.10 Elevated parking structures. Elevated
          parking structures shall be inspected on a regular
          basis, not to exceed 7 years, by a registered design
          professional in the Commonwealth of Pennsylvania
          contracted by the owner and at the owner’s expense,
          to verify the ability of the structure to adequately
          support the appropriate loads as defined by the
          building code. A letter stating the suitability of the
          structure to adequately resist the code-defined loads
          shall be kept on file at the code office.

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