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Recent Engineering Debacles
7

Recent Engineering Debacles

Recent Engineering Debacles

(OP)
HellO:

What have been the results of recent engineering debacles, like Boston's Big Dig concrete section that fell and killed some folks in a car or Katrina meant for PE's as far as liability and ethics are concerned?

RE: Recent Engineering Debacles

The results of engineering debacles:  Lawyers get richer.
 

RE: Recent Engineering Debacles

How was Katrina an engineering degacle?  That was a Catogory 5 storm (extreme conditions).  Where as the epoxy plug used for the concrete ceilng pannes was just a dum design (plain old gravity caused this failure).

Tobalcane
"If you avoid failure, you also avoid success."  

RE: Recent Engineering Debacles

Yes, if hurrincanes were engineered, Katrina would be a crowning jewel of engineering success, a perfect storm!. The levy designs were not engineering debacle. They were not designed for Category 5 storms or resulting surges and was well known.

In fact the existence of New Orleans city is awed engineering feat. Without the continuously running pumping system it would not exist.

Rafiq Bulsara
http://www.srengineersct.com

RE: Recent Engineering Debacles

Katrina was a Category 3 storm when it reached landfall, not 5

RE: Recent Engineering Debacles

More political than technical.  

The 'local' levees were not designed to withstand impact from barges, of which there are many.

No one seems to have authority or budget to seize and secure or dispose of derelict barges.

Some landowners would not allow access to the dry side for maintenance.  Yeah, I'd have thought eminent domain would take care of that, but in Louisiana, apparently it doesn't.

There was disagreement about who was responsible for maintenance.

There was no money for maintenance.

The only strictly technical failing that I see is a lack of structural redundancy in the levees.  The "I-walls" are constructed in segments, basically like tilt-up panels, with water seals but no structural linkage between them.  A barge hit tilts just one of them, producing two notch weirs, between the tilted panel and its neighbors.  

The barge owner of course doesn't report an allision, and the landowner doesn't have money available for excavating the water side mud and re-erecting the panel, nor authority to do it.   Those secondary levees were designed by USACE, which then assumed that maintenance would be conducted by local authorities, of which there are many.  .. and the finger- pointing goes round and round and nothing gets fixed.


 

Mike Halloran
Pembroke Pines, FL, USA

RE: Recent Engineering Debacles

I think most "debacles" occur when accountants, MBAs and Clients disregard what engineers are trying to do and, for the sake of making better business decisions and improving schedule, go and do whatever they want and bully the engineers into agreeing with them under the threat of losing business - or your job - if you don't.  

Regards,

SNORGY.

RE: Recent Engineering Debacles

Many failures of engineered systems (buildings, bridges, products, etc.) occur; however, few are caused by engineering failures. Most are caused by construction deficiencies or operational issues (poor maintenance, overloading/over-use, environmental deterioration, aging, etc).  Should engineering be done so as to countermand these possibilities or even inevitabilities?  No.  In general, some of that is balanced in the design (we design structures for say a 50-year life and pavements for 20 years, etc.); however, things don't last forever.  That's one reason most states have a statute of repose that negates an engineer's liability for design after a period of time, usually 10 or 15 years.

RE: Recent Engineering Debacles

"Most are caused by construction deficiencies or operational issues (poor maintenance, overloading..."

The perfect example of this scenario is the Hyatt Regency Walkway failure back in the early 80's.  It was due in part to overloading and crowd resonance (too many people plus dancing to a beat), but mainly due to a connection design modification that doubled the stress on the connection - contractor wanted something simpler and more buildable - $$$ for him - and the reviewers (engineers) missed it.

Unfortunately for us, there are many others.  It was immediately after this failure though that structural engineers' libility insurance premiums went through the roof.

Mike McCann
MMC Engineering

RE: Recent Engineering Debacles

That's a matter of perspective.  

One could rationally argue that it was an engineering debacle because the designers instantiated something that was difficult to implement and repair, and would be likely subject to a field modification, which turned out to be case.  Had the original designers instantiated something that met the aesthetics and was relatively easy to construct, the problem might have never occurred.  Bear in mind that the original design was not even conducive to an structural repairs, since it might have required the entire structure to be dismantled to just get to the middle sections.
 

TTFN

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RE: Recent Engineering Debacles

Seeds of debacles are sewn when an owner selects an engineering firm based on "price" or worse through an architect! Eventually, the unlucky ones pay the price and the "rewards" and lucky ones escape.

Add to this all non-technical people making project related decision and you have a mess at your hands.

Engineers themselves are not blameless either. Most large A/E firm cannot retain good engineers, some good engineers are turned into bad managers. After their stellar marketing team secures a project, their "designers" go to work. The results are usually sad, unfortunately not all come to light in time, of ever.


 

Rafiq Bulsara
http://www.srengineersct.com

RE: Recent Engineering Debacles

If greed, corruption or ignorance take over at any level, a debacle can result.

In my limited experience in construction, it is often at the contractor level. In automotive it has been mainly engineering being over ruled by marketing or styling or both.

If an engineer signs of on an unsound design because he will otherwise lose a job, that can be considered greed and corruption as he did sign off for profit.  

Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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for site rules
 

RE: Recent Engineering Debacles

Quote (msquared48):

The perfect example of this scenario is the Hyatt Regency Walkway failure back in the early 80's.  It was due in part to overloading and crowd resonance (too many people plus dancing to a beat), but mainly due to a connection design modification that doubled the stress on the connection - contractor wanted something simpler and more buildable - $$$ for him - and the reviewers (engineers) missed it.
Mike,

Are you sure about the overloading and resonance part?  It has been quite a while since I've seen/read anything on the subject, but I thought the overload was mentioned as it related to the changed design (inferior side-by-side rods design).  And from what I recall of the video one guest was taking at the time of the incident, no one one the walkway was dancing, they were just standing around talking to each other.  Unfortunately, the guy decided to change his camera's battery about a minute before the walkway actually collapsed, so there's no video of the actual collapse.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Recent Engineering Debacles

Yes, as there were a LOT of people on both walkways watching some event, and the music was playing, causing people to move in unison, increasing the load further in a cyclical manner.  The connection change was the Main problemn as you say, but the loading situation did not help.

Mike McCann
MMC Engineering

RE: Recent Engineering Debacles

The connection change just made the problem worse.  The original connection had significant problems as well.

I don't recall anything about resonance in the final report (which I just read through about six months ago).   

RE: Recent Engineering Debacles

In addition to the awkward construction, which led to the field modification by the contractor, the original system was underdesigned, and with the modification, there was basically no margin left.  If the original design had the appropriate design margins, the modifications might have survived the heavy loading.

TTFN

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RE: Recent Engineering Debacles

Usually an attempt to solve a natural problem includes unintended consequences.  Controlling the flow path of the Mississipi river is good for ship and barge traffic.  However the navigational solutions affect the normal silt in the river delta.  No silt and the land sinks.  Also, we engineer short-term solutions.  Nature has longer term consequences.

RE: Recent Engineering Debacles

JAE:

The people were watching a dance contest, so there was music, and could have been incidental rythmical movement from the crowd due to the music.

I am not saying that there was harmonic motion that could have incited a fundamental mode of the walkway.  What I asm saying is that the harmonics of the crowd could have caused a sinusoidal variance in the gravity load of the crowd on the walkway, cyclically amplifying the live load to the connection, already doubled in stress over the original design.   

Kind of the straw that broke the camel's back situation.

 

Mike McCann
MMC Engineering

RE: Recent Engineering Debacles

I have to say that it has been my recent experience that the quality of engineering being produced by "engineering" companies has been declining. In our case, when we see a sample of such lack, we issue RFIs etc, which usually lead to change orders, increasing the cost to the owner.

However I have been seeing some signs that the owners are starting to make the engineering firms pay for these change orders. In the past it was the contractor which had to pay, but then they realized finally what was happening, hired engineers of their own, and so passed the costs on up.

It has been my unfortunate experience that engineering firms have not been held accountable for engineering mistakes and omissions. Only in a very few high profile cases has this happened. This resulted in an increase of sloppily engineering.

RE: Recent Engineering Debacles

Whether lump sum or reimbursible the managers of large projects are consumed by the budget.  The design firms reduce their labor hours by providing several methods with the full support of the client company project managers.  Examples include providing less detail, outsourcing work to lower cost labor markets, packaging more design responsibility with equipment packages and expecting construction to handle fabrication details.  Whether a good or bad thing depends upon the locaiton of your seat at the table.

RE: Recent Engineering Debacles

Assigning change order blame is not that straight forward. Usually the roots are in the fact that you get what you pay for!

"Production house" A/E or E firms have bigger share of the blame as they generally believe in push the design out of the door and will worry about changes later.

In many cases owner would not pay enough fees or allow time to finish the design in detail, etc. We can start a separate and endless thread on this topic. So I would stop here.

Rafiq Bulsara
http://www.srengineersct.com

RE: Recent Engineering Debacles

Hyatt Regency: There was no field modification. The modifications were made by a detailer that was not an engineer and although the drawings were stamped upon review, the stamping engineer did not review the drawing or supervise the review of the drawings. There were as I recall, three levels of precast slabs supportted off of steel tubes hung by rods from the ceiling. There were several flaws to the design. The orginal design was designed as a single rod with a stuctural tube under the slab. A hole in the tube allowed the rod to pass through and the tube was held in place with a nut and washer. Thus each connection carried the weight of on slab. In the revised shop drawing, the tubes had two hole at each end. the rods only reached from slab to slab. then a new rod was inserted ino the hole and secured by the same bolt detail in the original design. This forced the connection to carry the load of all the above slabs, which exceeded its capacity. In addition, rather than using tubes, channles welded toe to toe were used and the welds were not structurall sufficent. Further the rods were not of sufficent  diameter to carry the load. Finally the washers used in the connection did not span the webs of the tubes and had the potential to punch through the tube. So it was not one error but several errors and as far as I know it was a change between the shop drawing detailer and the designer. As tragic as it was, it is an important reminder of how important the details are.

RE: Recent Engineering Debacles

I don't think it was ever intended to use tubes.  Flange-tip welded channels were detailed in the first drawings by the EOR Gillam.

 

RE: Recent Engineering Debacles

Texas A&M conducted a study of this under a NSF Grant # DIR 9012252.

It states "With many party-goers standing and dancing on the suspended walkways, connections supporting the ceiling rods that held up the second and fourth-floor walkways across the atrium failed, and both walkways collapsed onto the crowded first-floor atrium below. The fourth-floor walkway collapsed onto the second-floor walkway, while the offset third-floor walkway remained intact."

The dancing could not have helped but the report states the original design did not meet the bulding code requirements.

It was going to happen sooner or later.

Regards.

RE: Recent Engineering Debacles

I would not go so far as stating that a failure event was a certainty because the design failed to meet code.

Also, perhaps the grant covers many studies.  Searching for NSF Grant DIR 9012252 brings up illegal handling, storing, and disposing of hazardous wastes at a defense site.

http://ethics.tamu.edu/ethics/aberdeen/aberdee1.htm

RE: Recent Engineering Debacles

Seeing as how the best example brought forward so far occurred over twenty years ago, I think this thread is actually putting engineering in a very good light.

"Good to know you got shoes to wear when you find the floor." - Robert Hunter
 

RE: Recent Engineering Debacles

ewh, you don't consider the Big Dig accident of just a couple of years ago to be a good example of a serious screwup?

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Recent Engineering Debacles

Are we talking in the USA or also internationally. There have been quite a few bridge/building failures both in China and in India lately. They do not get a lot of publicity, but they certainly happen.

RE: Recent Engineering Debacles

JLSeagull,

Search for "Hyatt + walkway +collapse" in Google, you'll find it.

A structural engineer looking at the drawing of the reapproved shop drawings and looking at the loads would have found it to have eventually failed regardless of code.

Regards.

RE: Recent Engineering Debacles

Yes, the Big Dig was indeed a serious screwup; however it seems that most of the posts here are focusing on the Hyatt collapse, which did claim more lives.
That said, there really aren't many such catastrophies happening in the US, which, IMO, puts the US industry in a good light.

"Good to know you got shoes to wear when you find the floor." - Robert Hunter
 

RE: Recent Engineering Debacles

Let's also not forget
  • Challenger and Columbia
  • I-35W bridge
  • Schoharie Creek Bridge


  • And wasn't there a failure of the Teton Dam around 30 years ago?

    Good Luck
    --------------
    As a circle of light increases so does the circumference of darkness around it. - Albert Einstein

    RE: Recent Engineering Debacles

    I would need to search for the Schoharie Creek bridge.  However, the space shuttle design occurred in the 1970's and the I-35 bridge in MN was designed decades ago too.  Other debacles include the Bhopal India accident and numerous plant explosions.  I am sure that you can find recently designed plants that exploded or had major releases of toxic or hazardous substances.

    RE: Recent Engineering Debacles

    I believe the space shuttle failed because of decision made to launch outside of the 'design' temperatures. A decision which led to the engineer who was at the meeting resigning on the spot. So that wasn't a bad design as such, it was a bad decision and more of a management one than an engineering one.  

    RE: Recent Engineering Debacles

    If operation below zero degree C (below the design temperature) was unsafe, perhaps a better design could have included a temperature interlock.  Thus conscious intervention would be required to bypass the interlock for a low temperature launch.

    RE: Recent Engineering Debacles

    Interlocks only make things idiot- resistant.

    Nothing could make a machine manager- resistant.
    The combination of power and ignorance is unstoppable.

     

    Mike Halloran
    Pembroke Pines, FL, USA

    RE: Recent Engineering Debacles

    but there was no need for an expensive repair if it worked fine. Due to commercial and political pressures they launched when the outside temperature was to low (or lower than they had tested to). It was due to a seal not working due to lack of expansion at low temps. Look up the report I think the company at 'fault' was Thiakoll, (not sure if i spelt it right). It was a management decision, in fact the enginneer who said no was allegedlly told at the meetting  take your engineering hat off and put your management one on. They took a risk. Its like someone saying this building will take a load of x and a manager saying oh well we'll stick 2x on it anyway.
    I also don't think with respect a simple comment like why didn't they fit xxx when you have no idea of the design or system is not really helpful other than to throw possibly unwarrented critism at the designers.

    RE: Recent Engineering Debacles

    Indeed many of the so call "engineering disasters" were not from faulty engineering, but for a lack of a better word operator failure. The most notable of these is Chernobyl. The engineers know that the reactor was unstable below a certain power output, and placed many safeties to prevent operation in that region. Enter operators which disabled the safeties.

    The I-35 bridge was a similar situation. In this case a lack of preventive maintenance. No design will last forever without adequate maintenance.

    Another example of an engineering debacle was the Verazano Narrows bridge.

    RE: Recent Engineering Debacles

    My first marriage would qualify as an engineering debacle. I did learn you can get blood from a turnip.

    RE: Recent Engineering Debacles

    djs,

    The maintenance on the I35 bridge was not too good, but the gusset plates which failed were built as designed, half the thickness they should have been.  Then numerous inspections over the years failed to identify the problem, because the assumption was always that the gussets would have been properly designed.

    RE: Recent Engineering Debacles

    but could you not say the bridge was load tested to the design load many times and it was only when this was exceeded did a problem occur?

    RE: Recent Engineering Debacles

    No, it was never load tested to the design load. The condition when the bridge failed did not exceed the design loading, according to the reports.

    RE: Recent Engineering Debacles

    Quote (djs):

    Another example of an engineering debacle was the Verazano Narrows bridge.

    Please explain.  I've never heard of an engineering problems with the Verazano Narrows Bridge.  Or, are you off by 3000 miles and 20+ years and thinking of the Tacoma Narrows Bridge?

    RE: Recent Engineering Debacles

    Even Tacoma wasn't a debacle, as designed. Sure they came a cropper because of an unsuspected effect, any newish technology can suffer from that. The debacle was leaving it in use until it fell down, probably not an engineering decision.

     

    Cheers

    Greg Locock

    SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

    RE: Recent Engineering Debacles

    I don't know if this is one that has been mentioned, as I don't know the name of the bridge, but...

    I seem to recall seeing a video in a class on vibrations/resonance with a bridge twisting back and forth (CW/CCW) during extreme winds. I believe it was in Japan?

    Does anybody know anything more? Or is that too vague?

    -- MechEng2005

    RE: Recent Engineering Debacles

    That would be "The Gallopin' Gertie", Tacoma Narrows Bridge.

    RE: Recent Engineering Debacles

    I don't think that the Tacoma Narrows Bridge was really new technology, although some new technology did come from the failure. Historically bridges have progressed by pushing the limits of design until there is a failure. Then we all take a big step back and begin again. The Brooklyn Bridge was built  50+ years before the Tacoma Narrows Bridge, yet it has a cable stay system incorporated with the suspension system to stiffen it against such behavior. Other bridges excluded the stays but used relatively stiff decks to prevent such behavior. The Tacoma Narrows Bridge lacked both, pushing the limits too far. I think it was an engineering debacle caused by hubris from our "advanced" analysis techniques and understandings of materials. I agree that it was a much larger error to leave the structure in use, although I understand that attempts were made to stiffen it.

    RE: Recent Engineering Debacles

    see: http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge_(1940)#Design_and_construction

    The TNB design was on a theory proposed by its ultimate designer that allowed the bridge to use substantially shallower girders 8 ft vs. 25 ft for the conventional design.  It was this innovation that allowed the bridge to be built at the cost target.  

    The bridge collapsed only 4 months after opening, so "leave in it use" wasn't exactly a question.  In fact, the bridge collapsed almost coincidentally with the release of the report proposing structural solutions.

    TTFN

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    RE: Recent Engineering Debacles

    I agree with IRstuff on the girder depth problem.  That's what I learned in my bridge design class forty years ago, and this was beyond the edge of the envelope design.

    The failure was due to intermittent vortex shedding due to a constant wind speed that incited a primary torsional resonant frequency in the structure - a concept never priously investigated for such structures.  It is now...

    Since we have constructed two new suspension bridges at the same location with deep trusses.

    Mike McCann
    MMC Engineering

    RE: Recent Engineering Debacles

    The fairing solution to the Deer Island bridge was one of the recommendations for the TNB, 5 days before it collapsed.

    TTFN

    FAQ731-376: Eng-Tips.com Forum Policies

    RE: Recent Engineering Debacles

    What caused dancing bridges in modern times was the rejection of stiffening trusses in favor of deep girders. Karman vortices were generated by the cyclic generation of vortices beyond the beams. [Aerodynamicists are familiar with this in wing work.] Many bridges were built this way, but they were fixed in several ways; stays, trusses, etc.

    The Whitestone bridge in NYC was a contemporary that was stiffened after the fact. In later years the stiffening was removed after introducing smooth fairing in the bridge section profile.

    RE: Recent Engineering Debacles

    Again, I don't think this was innovation. Prior lessons learned were forgotten, and advances in practice gave misplaced confidence. To me this is clearly a debacle. Below is a discussion from the Washington State DOT's website discussing the failure. The full article can be read at http://www.wsdot.wa.gov/tnbhistory/Machine/machine3.htm


    "Blind Spot"-- Design Lessons of Gertie's Failure
    At the time the 1940 Narrows Bridge failed, the small community of suspension bridge engineers believed that lighter and narrower bridges were theoretically and functionally sound. In general, leading suspension bridge designers like David Steinman, Othmar Amman, and Leon Moisseiff determined the direction of the profession. Very few people were designing these huge civil works projects. The great bridges were extremely expensive. They presented immensely complicated problems of engineering and construction. The work was sharply limited by government regulation, various social concerns, and constant public scrutiny. A handful of talented engineers became pre-eminent. But, they had what has been called a "blind spot."

    That "blind spot" was the root of the problem. According to bridge historian David P. Billington, at that time among suspension bridge engineers, "there seemed to be almost no recognition that wind created vertical movement at all."

    The best suspension bridge designers in the 1930s believed that earlier failures had occurred because of heavy traffic loading and poor workmanship. Wind was not particularly important. Engineers viewed stiffening trusses as important for preventing sideways movement (lateral, or horizontal deflection) of the cables and the roadway. Such motion resulted from traffic loads and temperature changes, but had almost nothing to do with the wind.

    This trend ran in virtual ignorance of the lessons of earlier times. Early suspension bridge failures resulted from light spans with very flexible decks that were vulnerable to wind (aerodynamic) forces. In the late 19th century engineers moved toward very stiff and heavy suspension bridges. John Roebling consciously designed the 1883 Brooklyn Bridge so that it would be stable against the stresses of wind. In the early 20th century, however, says David P. Billington, Roebling's "historical perspective seemed to have been replaced by a visual preference unrelated to structural engineering."

    Just four months after Galloping Gertie failed, a professor of civil engineering at Columbia University, J. K. Finch, published an article in Engineering News-Record that summarized over a century of suspension bridge failures. In the article, titled "Wind Failures of Suspension Bridges or Evolution and Decay of the Stiffening Truss," Finch reminded engineers of some important history, as he reviewed the record of spans that had suffered from aerodynamic instability. Finch declared, "These long-forgotten difficulties with early suspension bridges, clearly show that while to modern engineers, the gyrations of the Tacoma bridge constituted something entirely new and strange, they were not new--they had simply been forgotten."

    An entire generation of suspension bridge designer-engineers forgot the lessons of the 19th century. The last major suspension bridge failure had happened five decades earlier, when the Niagara-Clifton Bridge fell in 1889. And, in the 1930s, aerodynamic forces were not well understood at all.

    "The entire profession shares in the responsibility," said David Steinman, the highly regarded suspension bridge designer. As experience with leading-edge suspension bridge designs gave engineers new knowledge, they had failed to relate it to aerodynamics and the dynamic effects of wind forces.
     

    RE: Recent Engineering Debacles

    The choice between "innovation" and "debacle," I think, is really a matter of semantics.  

    The TNB's depth to width ratio of 1:350 is not, and was not, found on any bridge.  To that degree, it was an envelope push, hence, an innovation.  The fact that history was ignored, and that only deflection theory was used, as exemplified by Moisseiff's 1933 paper on lateral loading that justified such as design, was a debacle.

    TTFN

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    RE: Recent Engineering Debacles

    Hang on, were previous suspension bridges built deeper in order to eliminate aerodynamic instability, or for other reasons which then happened to make them immune to flutter?  

    Cheers

    Greg Locock

    SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

    RE: Recent Engineering Debacles

    I think it was more the case that the "traditional" design used trusses, which were design to carry the entire load of the roadway and lateral forces.  Moisseiff and others showed that the cables them selves carried a substantial portion of the static deflection loads, so the trusses weren't needed for that, and that smaller plate girders could handle the remainder of the static loads.

    However, it was also about that time that people finally understood the effects of the aerodynamics, which were drastically influenced by the blunt plate girders.  Moreover, it was clear in hindsight that the stiffer truss designs were also stiffer in torsion, but they were never intentionally designed with that in mind.

     

    TTFN

    FAQ731-376: Eng-Tips.com Forum Policies

    RE: Recent Engineering Debacles

    Quote:

    The failure was due to intermittent vortex shedding due to a constant wind speed that incited a primary torsional resonant frequency in the structure

    It wasn't forced resonance due to vortex shedding, it was aeroelastic flutter.

    RE: Recent Engineering Debacles

    The Brooklyn Bridge is accepted as the first modern suspension bridge. It was designed by Roebling. According to Niels J Gimsing in Cable Supported Bridges – Concept and Design, 1983,

    "During the period when Roebling worked as a bridge designer in the United States, a fatal bridge disaster took place when the suspension bridge across the Ohio River at Wheeling was destroyed by the wind in 1854. This accident made a strong impression on Roebling and inspired him to take several measures to increase the stiffness of suspension bridges beyond what is obtained by the cable itself. In his bridges, following the Wheeling disaster, he therefore introduced stiffening trusses with a considerable bending stiffness and stays to supplement the pure suspension system."

    As quoted on the website http://www.gribblenation.com/swparoads/essays/nationalrd/wheeling.html , here is a description of the Wheeling Bridge failure. It sounds remarkably similar to the Tacoma Narrows Bridge failure.

    "For a few moments we watched it with breathless anxiety, lunging like a ship in the storm; at one time it rose to nearly the heighth of the towers then fell, and twisted and writhed, and was dashed almost bottom upward. At last there seemed to be a determined twist along the entire span, about one half of the flooring being nearly reversed, and down went the immense structure from its dizzy heighth to the stream below, with an appalling crash and roar. Nearly the entire structure struck the water at the same instant dashing up an unbroken column of foam across the river, to the heighth of at least forty feet! "
     

    RE: Recent Engineering Debacles

    The three gorges dam is supposed to silt up in less than 20 years.....

    RE: Recent Engineering Debacles

    The issue about wind loads is correct.  I have seen several failures of buildings that were designed and constructed (reasonably) well, that did not adequately consider uplift.  These buildings were in south Florida, built prior to 1975.  Hurricane Andrew (1992) showed their deficiencies.

    We found masonry structures with tie beams and joist "pockets" (a common technique) that had no uplift restraint other than dead load.  Not good enough when the wind speed is 140 mph+.  Codes at the time required nothing like that...for instance, the 1969 version of the Standard Building Code required a design pressure of 25 psf for any building up to 30 feet in height.  That same building today, in South Florida, would require an uplift pressure of up to about 40 psf...a 60 percent increase in pressure.

    RE: Recent Engineering Debacles

    A few years ago, a partial collapse of a freeway ramp occurred in Albany NY. Review of the bridge inspection reports showed the expansion rocker bearings had been overextended for years, but no one really did anything about it.

    https://www.nysdot.gov/divisions/engineering/structures/repository/manuals/dunn_failure_report_10-05.pdf

    On the other hand, the Department's response and forensic engineering report did not try to obfuscate things, which was not an ethical failure.


    Poughkeepsie Galleria parking deck collapse: http://en.wikipedia.org/wiki/Poughkeepsie_Galleria#Parking_garage_collapse

     

         "...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

    "I'm searching for the questions, so my answers will make sense." - Stephen Brust

     

    RE: Recent Engineering Debacles

    I just got an e-mail tody about 12 story building that fell over in China. The construction crew excavated dirt from one side of the building, put it on the other. It rained, which allowed the soil to act like a fluid. The imbalance of dirt created a shear load in the dirt pushing the building over.

    You can find this on teh internet with a Google search. Very interesting.

    RE: Recent Engineering Debacles

    A recent debacle in my company was when our plastic gear supplier sourced the material in China as a cost reduction. The material was offspec Acetal, the source not certified, and the stuff hit the fan. All this in an ISO9000 company.

    The company was sold twice after losing the contract; a premium line of cars suffered widespread infant mortality.

    DO NOT SOURCE CHINA!

    RE: Recent Engineering Debacles

    Doesn't ISO9000 mean almost nothing?

    CDG, Los Angeles Civil Engineering specializing in Hillside Grading
    http://cdg-ca.com

    RE: Recent Engineering Debacles

    ISO9000 means as much or as little as you want. It can be summarised as "Document what you do, do what you document".

    So if you have a sourcing procedure that says "Source material from the cheapest supplier, do not verify its quality".

    Then you have complied with ISO9000.

     

    Cheers

    Greg Locock

    I rarely exceed 1.79 x 10^12 furlongs per fortnight

    RE: Recent Engineering Debacles

    Greg's take is absolutely correct.  

    Our previous certification for ISO9000 was hung up because our process-oriented procedures were so complex that we had trouble documenting that we were following the process.  The process was then changed to a two-page thing, and we got certified the following year.

    TTFN

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    RE: Recent Engineering Debacles

    Quote (plasgears):

    A recent debacle in my company was when our plastic gear supplier sourced the material in China as a cost reduction.

       You have brought this up in thread16-221050: Anybody experience bad quality fasteners from China? and in thread769-227602: Hazard of Sourcing to China.  Your customer demanded a 10% price reduction, and your company passed it on to your supplier.  You all got the quality you deserved, and by the sound of it, the customer feedback you deserved.

       This is more of a management screwup than an engineering one, unless safety was involved.

                   JHG

    RE: Recent Engineering Debacles

    drawoh: Don't engineers have a bit of say regarding the cost reduction?  I wouldn't cheap out on parts on our Civil plans based on a client wanting to be cheap on the project.

    I am curious about the Vegas City Center and who was cheaping out when they built the Harmon.  Probably no one will ever know.

    CDG, Los Angeles Civil Engineering specializing in Hillside Grading
    http://cdg-ca.com

    RE: Recent Engineering Debacles

    I have at times had some very good quality out of China and some junk out of the USA

    Not typical I admit, but it depends on who you deal with and how you deal with them no matter where you are.

    I have seen two toolmakers in Aus within a few blocks of each other, one made absolute junk, like worse than anything I ever saw out of China and the other made as good as the best from Switzerland.

    I also recently rewrote quality manuals etc for a company who repeatedly got major non conformances and were on probation with one more chance to not lose their accreditation. I rewrote the manual to change the emphasis from we will be the world leader in everything to we will identify business that best matches our resources and competitive advantages and work with the identified customer for best fit to optimise profits and business development.

    We now have one minor non conformance which has been fixed. I guess he will tick that off and find another in the next audit.

    Regards
    Pat
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    RE: Recent Engineering Debacles

    This thread has drifted a bit - from attempting to control the Mississippi River on one end and manufacturing quality control on the other end of the spectrum.  One of our inspectors often complains about the lack of suitable manufacturing processes at our primary control valve suppliers manufacturing shop.  Second rate quality control is bad but isn't really an engineering debacle.

    OTOH, our society chooses to control things like the MS River among the pork projects initiated by our elected officials.  Upon the next "New Madrid" earthquake the Mississippi River may choose a different course.  Rivers do this without earthquakes but something like the New Madrid event are likely causes of significant change.  When the Mississippi River changes course it will likely destroy millions of acres of rural land and cause some significant changes for the industrialized areas along the current route.  Only then will anyone ask why the Corp of Engineers did not prevent this.  Stay tuned.

    RE: Recent Engineering Debacles

    I think this topic can drift very easily because engineers basically create everything there is, and a lot of those creations can destroy people's lives pretty quickly.

    Civil Development Group, LLC
    Los Angeles Civil Engineering specializing in Hillside Grading
    http://cdg-ca.com

    RE: Recent Engineering Debacles

    Opps

    I missed my point on the quality comments.

    The point was, we constantly basically failed QC audits. I rewrote the manual, did no changes to procedures and specifications nor conformance to specification, but got a good pass on the next audit.

    The point is for ISO9000 you can specify where you want to draw the quality line.

    Regards
    Pat
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    RE: Recent Engineering Debacles

    As the topic has seemed to drift into non recent engineering debacles here's a European angle on some horrendous incidents.

    1. Tay bridge disaster 1879 (75 people killed). Cause- low quality Cast iron used in construction.

    2. Allenader Keilland - 1980 -123 people killed. Cause poor weld caused fatigue crack and failure of one part of the structure causing collapse.

    3. Eschede train disaster 1998. 101 dead. Cause. Fatigue of the composite wheels which were fitted at the insistence of the management to improve ride handling.

    Funny enough when I list these (and other failures) in my fatigue course for practicing engineers hardly any of them have heard of any of these incidents. Which brings to my mind the phrase... Those who don't learn from history are doomed to repeat it!
     

    www.priamengineering.co.uk

    RE: Recent Engineering Debacles

    Yes, people are killed as a result of engineering gone awry.  It's always a tragedy and we engineers always strive to do better.

    But if anywhere near the number of people were killed as a result of engineering errors as are killed by MEDICAL errors, there'd be a Royal Commission on the subject in a heartbeat...

    A little perspective goes a long way!

     

    RE: Recent Engineering Debacles

    Doctors errors kill one patient at a time. Engineering errors can kill in greater numbers.

    Peter Stockhausen
    Senior Design Analyst (Checker)
    Infotech Aerospace Services
    www.infotechpr.net

    RE: Recent Engineering Debacles

    How about gas pedals, so far it's been one at time since last August.  

    RE: Recent Engineering Debacles

    True, but one error (or series of errors more likly) caused Toyota's problem.

    Peter Stockhausen
    Senior Design Analyst (Checker)
    Infotech Aerospace Services
    www.infotechpr.net

    RE: Recent Engineering Debacles

    On the surface it appears that Toyota stepped up to the plate quite well.  They found a problem.  Their initial diagnosis was simple but wrong.  They stopped sales of the defective vehicles.  They are going to make good on the problem.

    Ford quality improved lots over time too.  However 10 years ago the news was covered with the Firestone mess.  I rented a trailer a couple of years ago.  The U-Haul agent first verified that I would not be using a Ford to pull the trailer.

    I have owned each of the above and currently drive a Buick SUV and my spouse drives a Buick sedan.  I can assure that GM quality is improved but not close to my expectations of Toyota.

    RE: Recent Engineering Debacles

    I have to disagree slightly with the previous post.  My stepdaughter's son-in-law bought a subject vehicle  with his year end bonus in December. The vehicle was made in the October and it has it has malfunctioned twice and is now parked.  According to the news the problem was realized in August even though there are reports of earlier incidents.  
    I listened to one report that stated that the company was working on the problem in September.  He has been told by his very large dealer that any help will be 8 to 10 weeks out at a minimum.
    I've been trying to catch the news today as the head of of the US operation was supposed to have an interview to explain things to the owners and clear the air.
    I think as stated by one automotive reported it appears that Toyota put everything in the push to be the biggest car manufacturer around.  Automotive executives have dumbed down to the level of a used car salesman, tell them anything they want to hear and mean nothing.
     

    RE: Recent Engineering Debacles

    Priam,

    A native Yankee, but I'd heard of two of your listed incidents.  The second I'd not heard of, but the name sounded vaguely familar...a Google search turned up "Alexander Kielland", a floating oil platform in the North Sea...I'd heard about that too...is it the incident to which you're referring?
     

    RE: Recent Engineering Debacles

    Supposedly, that Toyota problem has been around for a while; I wonder if it has anything to do with when they started production in the US...

    TTFN

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    RE: Recent Engineering Debacles

    IRstuff,
    No I don't think so, as they mention other countries especially India.

    The fix is a "precision" piece of metal that attaches to pivot of the accelerator petal inside the car.
    Evidently the big concern among the car geeks and aficionados is how could this keep the car from accelerating.  Everything I've watched is that company officials dance around the question of possible computer problems.
    The phrase that scares a lot of people is "you have to trust us on this" referring to the question of a computer glitch.
     

    RE: Recent Engineering Debacles

    The metal is supposed to keep the pedal from sticking in the floored position; this relates to the supposed problem of the floor mats keeping the pedal from coming back up.

    Whether this is the actual solution or not remains to be seen.

    TTFN

    FAQ731-376: Eng-Tips.com Forum Policies

    RE: Recent Engineering Debacles

    Did not Audi suffer similar problems about 15-20 years ago?  I recall reading that the problem then was that they hadn't accounted for the fat feet of affluent American women buying their cars, or some such.

    RE: Recent Engineering Debacles

    Maybe because of high heels?  While I agree the US has a higher percentage of overweight people, I can't imagine that weight difference equates to foot sizes so different it ends in stuck pedals.

    Maybe I joke I just didn't get, bt?

    Dan - Owner
    http://www.Hi-TecDesigns.com

    RE: Recent Engineering Debacles

    I think Audi decided that mostly people were just pushing too hard on the wrong pedal when they panicked.

    The Toyota pedal fix reduces the (deliberately induced) friction in the pedal assy, by preventing the friction blades from engaging as deeply. These are designed to reduce the required pedal pressure when maintaining a constant pedal angle, but through wear or environmental factors or whatever the friction can increase too much. Hoiking the pedal back up with your toe would also be a 100% fix.

    There are continual mumblings about software problems as well.




     

    Cheers

    Greg Locock


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    RE: Recent Engineering Debacles

    From the news today.  

    http://www.latimes.com/business/la-fi-toyota-wozniak3-2010feb03,0,3057333.story

    I can not understand how a stuck accelerator pedal in something less than the wide open position will cause the throttle to go wide open and the vehicle to accelerate.  Yes I know it happens in race cars but only when you have pedal pushed to the floorboard.  Also on some old Stroberg Single Barrel carburetors if the linkage came off the throttle plate would go wide open, corrected by a small spring.    

    RE: Recent Engineering Debacles

    Let's see.

    Woz's car isn't part of the recall as it doesn't have the wrong throttle pedal.

    He has a problem with the cruise control acting up, not the throttle pedal.

    The circumstances he describes are not the ones that 'everybody' else is complaining about.

    Still, Toyota are going to have a look at it. That's nice for him.

    Cheers

    Greg Locock


    New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies  http://eng-tips.com/market.cfm?

    RE: Recent Engineering Debacles

    syd,

    Most people's reaction to s stuck pedal (at any angle) is to stomp it and see if it unsticks.  Regardless of that, if the DBW system decides to go full-throttle, it really doesn't matter at what angle the gas pedal is being pressed.

    Woz's story is also starting to get banged around a bit.  He posted his method for making the cruise control go wonky and some are leaning towards operator error.  I've read their reasoning, but I'm not sure if I buy it as a possible cause of user error.  The naysayers are suggesting his repeated pressing of the accel button is faster than what the tiny Prius can keep up with considering its small power level.  I don't use cruise control very often, but any time I have, it has stopped trying to accelerate the moment I stopped pressing the button... pressing the button 5 times when it could only accelerate through 3 presses worth of speed meant I only got the 3 speed increase, not 2 more over the next several seconds.

    Dan - Owner
    http://www.Hi-TecDesigns.com

    RE: Recent Engineering Debacles

    Back to the Boston Big Dig Tunnel collapse - My understanding is that the manufacturer of the epoxy was sued and settled; even though they provided two different kinds of epoxy, and the wrong type was used for the ceiling lugs which collapsed.

    Either the engineers specified the wrong epoxy, or the installers used the wrong epoxy (neither of which were sued); how is it the manufacturer's fault?

    RE: Recent Engineering Debacles

    "On the surface it appears that Toyota stepped up to the plate quite well.  They found a problem.  Their initial diagnosis was simple but wrong.  They stopped sales of the defective vehicles.  They are going to make good on the problem.

    As I read more regarding this Toyota issue I support them less.  Regard the previous utterance to be withdrawn, recanted or whatever the proper phrase might be.
     

    RE: Recent Engineering Debacles

    Mac,

    I think the original Audi article was somewhat poking fun about the idea, but it implied that it had been seriously debated by Audi at some point.

    Does the software on a by-wire throttle system not detect if the brake is depressed, and reduce/eliminate the throttle input if that is the case?  Shouldn't it (power-braking hotrodders need not reply)?

    RE: Recent Engineering Debacles

    DanDel: Maybe the company thought they had a high chance of losing so they settled.  The more I read about who gets sued for what in this Country scares me to know end as a business owner.

    macgyvers2000: I thought I recognized your signature from the s2ki forums.

    Civil Development Group, LLC
    Los Angeles Civil Engineering specializing in Hillside Grading
    http://civildevelopmentgroup.com
    http://civildevelopmentgroup.com/blog

    RE: Recent Engineering Debacles

    brandon,  what's your handle?



    Dandel, If memory serves, I believe the recommended the correct epoxy during the planning stages, but shipped out the incorrect epoxy months later when design changes were in play (I think the person responsible for filling the order did not comprehend the changes that were being planned).  but it has been a while since I looked at the docs...

    Dan - Owner
    http://www.Hi-TecDesigns.com

    RE: Recent Engineering Debacles

    Quote (btrueblood):

    Did not Audi suffer similar problems about 15-20 years ago?  I recall reading that the problem then was that they hadn't accounted for the fat feet of affluent American women buying their cars, or some such.  

       They hit the wrong pedal.  P.J.O'Rourke wrote this up in Parliament of Whores.

       I have a book at home which I will have to look up.  I can't remember the title at the moment.  They described an accident in which a cop hopped into a police van, and it took off screaming and ran a couple of people over.  There was an interlock that prevented the driver from shifting out of park without pressing the break.  Eventually, it was discovered that the police lights on top of the van, disabled it.

       I think that the real failure is that people hop into automatic transmission cars and hit the gearshift and brake all in one motion.  This is especially dangerous if you are twisted around in your seat, looking out the back window.  

       If you sit squarely in the driver's seat and place your foot on the brake, you will have time to calmly figure out why the engine is roaring and screaming.   

                   JHG

    RE: Recent Engineering Debacles

    DanDel,

    There were a total of 15 defendants in the Big Dig lawsuit filed by the family of the lady who was killed.  Total of $28 million.  The attached article reports that $10 million of this was in early settlements by the fastener suppliers.

    http://www.usatoday.com/news/nation/2008-09-30-big-dig-death_N.htm

    RE: Recent Engineering Debacles

    Pure supposition on my part, the product of warped mind.

    I've talked to two people who have had acceleration problems and the only common thread was in every incidence (8) they were talking or texting using the same brand of cell phone.  Wouldn't it be blivit if a certain transmitted group would cause the computer to call for acceleration.  The lawyers are already salivating I don't know if they could take additional euphoria.  

    RE: Recent Engineering Debacles

    "Does the software on a by-wire throttle system not detect if the brake is depressed, and reduce/eliminate the throttle input if that is the case?  Shouldn't it"

    I drove 4 different makes of car yesterday. All of them allowed full brake+WOT as a valid control state.

    If you don't allow throttle+brake then there are going to be cars abandoned all over the country, as there are circumstances where it makes sense.

    Howver I suspect that there will be some sort of longer term outcome, either an explicit 'stop engine' control (such as a key that you can turn), or perhaps smarter software that recognoises panicky braking and that then idles the engine.  

    Cheers

    Greg Locock


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    RE: Recent Engineering Debacles

    I would have thought a steep uphill start requires left foot brake with throttle applied until the engine has sufficient pre-load to prevent roll back when the brake is released. Also as a hot rodder, I won't be quite so easily silenced or dismissed. I like to left foot brake and be first off as the lights turn green.

    Regards
    Pat
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    RE: Recent Engineering Debacles

    I would have a hard time left foot braking and working the clutch at the same time.  That is why I like the hand break for those hill starts. For an auto trans, I only do that when pulling out of a tight parking spot on a hill.

    I agree with Greg, sometime you need to do certain things.  It irritates me when there are governors applied too close to speeds you may travel.  I think it is dangerous.

    RE: Recent Engineering Debacles

    Ummm

    If it's a manual transmission there is no problem with the drive by wire as you simply depress the clutch.

    To hill start you heel and toe the throttle and brake and of course left foot the clutch.

    This thread was pretty much all about automatics I think.

    Regards
    Pat
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    RE: Recent Engineering Debacles

    Pat,

    The emergency brake should be used on steep grade hill starts.  Engage brake, apply light gas, release brake.

    Dan - Owner
    http://www.Hi-TecDesigns.com

    RE: Recent Engineering Debacles

    Only works on steep clay slopes, with an auto, if you had the non existent 4 wheel park brake. The 4wd training course we do explicitly includes a bit of a track where throttle +footbrake is the only way to get an auto up the slope. The lesson learned is that you'd rather be in a manual. - put it in low, kill the engine, clutch out, release all the brakes, key on.

    Seriously, there are many examples for people who actually use their vehicles where you need to combine both controls. It may not be a big deal for city dwellers, that is not the point.



     

    Cheers

    Greg Locock


    New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies  http://eng-tips.com/market.cfm?

    RE: Recent Engineering Debacles

       My reference is Inviting Disaster -- Lessons from the edge of technology by James R. Charles.  Google Officer Thomas Sawina.

       I have never used the parking brake to start my manual transmission car up a hill.   

                   JHG

    RE: Recent Engineering Debacles

    I had a throttle cable freeze and stick in the full throttle position once- on a manual transmission car.  Putting your foot on the clutch is  a recipie for major engine damage unless you also shut off the ignition...

    RE: Recent Engineering Debacles

    Pat,

    I didn't say that was the method I used, just that it's what the average driver should be doing.  In my manual cars on steep hills, I just switch very quickly from brake to gas... I roll a couple of inches, at best.

    Dan - Owner
    http://www.Hi-TecDesigns.com

    RE: Recent Engineering Debacles

    From the Wall Street Journal about 40 minutes ago.

    "Toyota has recalled millions of cars over a defect that causes sudden acceleration.  The company says it has the fixes in hand, and that dealers can begin making the cars safe, but the U.S. Transportation Department is investigating claims that electromagnetic interference might be causing Toyota electronic throttle systems to malfunction."

     

    RE: Recent Engineering Debacles

    Thanks drawoh, that is exactly where I read it.

    "smarter software that recognoises panicky braking and that then idles the engine.   "

    Ok, that sounds right Greg, and more what I was thinking, even if it didn't come thru my fingers to keyboard.  The concept of opposing inputs requiring a fail-safe condition.  Better to fail to a car that won't go, than to one that won't stop.
     

    RE: Recent Engineering Debacles

    macguyvers2000:  travanx is my handle everywhere.  Actually if you search stolen porsche 993, you will find what I really think about people. UGH!

    From the current discussion it sounds as people should drive a manual car!  Problem so solved.  Every single time I see Toyota mentioned in the last week or so, I think what is the Ferrari 458 Italia thinking!!!  Supposedly the car is only auto because the computer is so sophisticated that a manual is not possible.

    Does a smart person only have to come out with secure wifi car ECU updating program now??  When I mention an invention so far it has been made within 3 years.

    Civil Development Group, LLC
    Los Angeles Civil Engineering specializing in Hillside Grading
    http://civildevelopmentgroup.com
    http://civildevelopmentgroup.com/blog

    RE: Recent Engineering Debacles

    Quote (brandoncdg):

    ...

    From the current discussion it sounds as people should drive a manual car!  

    ...

       I think manual transmissions are safer because manual transmission drivers are better.  In parking lots and on narrow roads with children playing, you can drive in first or second gear and rely on the engine noise to tell you how fast you are doing.  There is no need to glance away from the road to scan your instruments.  On the other hand, I would guess that most of the cars on this website have manual transmissions.

       One of my understandings about all this is that the engine and automatic transmission have not been made that can overpower your brakes, if you have applied them.  A car is a piece of heavy machinery which must be treated with respect.  The least reliable component is the nut that holds the wheel.  

                   JHG

    RE: Recent Engineering Debacles

    unclesyd,

       That article was interesting, especially the stuff about drive-by-wire.  

       Modern fighter aircraft are inherently unstable, and are human controllable because a computer automatically provides rapid control corrections.  Some aircraft are huge.  How feasible would it be for a person of average size and build to manually control a Boeing _747 or an Airbus_A380?  These aircraft at the very least, have massively power assisted controls.

       What problem would drive by wire solve?  Are most accidents caused by people unable to master complex control movement?

       I was on a bus a few years ago that was headed down a snowy, slippery road.  The driver decided he was losing control, so he put the thing in the ditch.  The alternative was to slide down a hill and somehow recover control and avoid a lake.  

       Would a drive by wire bus have allowed him to do this?

                   JHG

    RE: Recent Engineering Debacles

    I think the older planes were fly by hydraulics, not wire, e.g., DC-10.

    FBW for fighters is not because the computer is faster, per se, but because the stability equations are not solvable by the pilot, even if he had more time.

    TTFN

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    RE: Recent Engineering Debacles

    Throttle by wire is cheaper, more reliable, marginally better for crash, quieter, lighter and offers easier implementation of features than a cable operated throttle.

    You have to look at these things from a system perspective.

    Cheers

    Greg Locock


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    RE: Recent Engineering Debacles

    Greg,
    Just a question, but where is the cost savings in throttle by wire? It just seems counter intuitive to me.  I'd think some cabling vs a bunch of computers would be cheaper. I'm sure you're right but could you elborate? I'm sure there is something I'm overlooking, but it isn't obvious to me.

    RE: Recent Engineering Debacles

    For airplanes, it's not about cost, per se.  Weight of hydraulics, elimination of handling costs of noxious fluids, ability to have redundancy, ability implement high-performance stability algorithms, ability to distribute processors and sensors.

    Note that that cabling is often already present for the sensors, so a slight addition to the existing harness in some cases, and simplification of the harness in others, results in substantially higher performance.  

    TTFN

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    RE: Recent Engineering Debacles

    There's already a throttle position sensor, so the ECU can know the demand.
    There's already a throttle actuator, for cruise control, or at least a snap-shut damper or burp valve.
    There's already computing power available, for 'free'.
    So removing the mechanical linkage or cable provides a cost savings.
    ... which is mitigated by the risk and cost of litigation or legislation over the reliability of the computer code.
    ... which is always postponed and politicized and rushed, and is one of the most expensive components of computerized systems.


     

    Mike Halloran
    Pembroke Pines, FL, USA

    RE: Recent Engineering Debacles

    GregLocock,

       Throttle by wire does not bother me.  The throttle system is one system that can malfunction, whether it is mechanical, electronic, or computer controlled.  You still have the gearshift and the brakes, and some of us have clutches.

       I was more concerned about the entirely driven by wire cars described in Dvorak's article.  Now you have the possibility of a central malfunction that cannot be overridden.  There are a lot more cars on the road than there are fighter planes and airliners.  They are not as well maintained, and the stuff happening around them is a lot less predictable.  

                   JHG

    RE: Recent Engineering Debacles

    I would have no problem traveling by cars controlled by computers. It's the transition where there are some controlled by computers and some by people that has me scared.

    Peter Stockhausen
    Senior Design Analyst (Checker)
    Infotech Aerospace Services
    www.infotechpr.net

    RE: Recent Engineering Debacles

    What about computer-controlled steering?  Steering racks don't exist in all vehicles (electric steering), so what happens as we move forward in technology and a computer error decides to turn us left instead of right?

    Dan - Owner
    http://www.Hi-TecDesigns.com

    RE: Recent Engineering Debacles

    drawoh- I didn't read the Dvorak article as I usually find old gum wrappers are more sensible, he's mostly a troll. OK, that article wasn't too bad.

    "I was more concerned about the entirely driven by wire cars described in Dvorak's article.  Now you have the possibility of a central malfunction that cannot be overridden."

    Yup, that's how it'll pan out. So the question is, is there a net cost benefit to society in an Everything By Wire car? I don't know. I have seen a presentation intimating that the technology will be deployable by 2020, and I imagine there are a lot more people thinking this through than there were.

    I suppose one bright spot is that by and large we have managed to get ABS and ESC introduced without causing too many accidents caused by system failures.  

    Cheers

    Greg Locock


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    RE: Recent Engineering Debacles

    The thing that worries me about doing anything important by wire is ... not the wire, but the connectors, which are the least reliable part of any competently designed electronic device today.

    They may be getting worse.  I submit that we are starting to reap the fruit of the RoHS initiative in that respect.

     

    Mike Halloran
    Pembroke Pines, FL, USA

    RE: Recent Engineering Debacles

    With respect to the recent death of Georgian luger Nodar Kumaritashvili, is their a track engineering component to the accident?
     

    Good Luck
    --------------
    As a circle of light increases so does the circumference of darkness around it. - Albert Einstein

    RE: Recent Engineering Debacles

    It has been said to be so.
    There have been complaints that the track is too fast, fastest in the world.  There is also some discussion about the inspection committee's recommendation for higher guard rails. The part that I hears mentioned a wooden fence to keep people on the track which specifically mentioned the  area where he went over.
    The politics are so thick around the games i don't think you will ever hear anything about whys and wherefores.  

    I think a wooden fence or a small mesh net would be better that a steel support column.  

    RE: Recent Engineering Debacles

    Perhaps look at the more mundane "The Design of Everyday Things", Donald Norman and similar ideas.


    Would a Toaster be allowed if it were a new design (you do remember when you used a knife to extricate the burnt bread when it was still on winky smile - safe as houses, wouldn't be without it.

    Philip

    RE: Recent Engineering Debacles

    Today will be interesting as it has been reported that Toyota has replicated the acceleration excursions caused by a "short circuit" in the electronic control system first reported by ABC.   
    The irony of this scenario was the diagnostic system gave no error codes even after several excursions.

    http://www.cbsnews.com/stories/2010/02/22/cbsnews_investigates/main6232884.shtml

    RE: Recent Engineering Debacles

    syd,

    That link mentions documents talking about surging. Nothing to do with short circuits.

    The documents are a red herring.  People are going to exclaim "See?  I told you so!", but it looks like nothing more than a transmission that can't find the proper gear for a specific small range of speeds, like it keeps changing between 3rd and 4th gear, leading to surging as it downshifts.  Not dangerous, just annoying as hell.  You can reproduce it easily by going up a mountain at a high altitude with a lower-horsepower car... few ECUs are programmed to properly handle that, so it hunts between the top couple of gears.

    I'm curious to know more about the supposed short circuit, though...

    Dan - Owner
    http://www.Hi-TecDesigns.com

    RE: Recent Engineering Debacles

    Got it... David W. Gilbert, PhD., Professor of Automotive Technology, Southern Illinois University Carbondale.  Here's his testimony:
    http://energycommerce.house.gov/Press_111/20100223/Gilbert.Testimony.pdf

    Very enlightening.

    Quoting from various parts of the document:

    Quote:

    The Accelerator Pedal Position (APP) sensor was identified in the review of manufacturers' service literature as a significantly important ETC input for all vehicles used in the study.

    With the two APP sensor signals shorted together through a varying range of resistances, all four Toyota vehicles tested thus far reacted similarly and were unable to detect the purposely induced abnormality. The types of signal faults introduced into the APP circuit should have triggered the vehicles' ECM to illuminate a warning lamp within seconds. The ECM should have then set a Diagnostic Trouble Code (DTC), entered the vehicle fail‐safe mode, and reduced engine speed and/or power.  When the two APP signal
    circuits are shorted together, the redundancy of the APP circuit design is effectively nullified and lost.

    In addition, the shorted APP signal circuits were connected momentarily to the sensor's five‐volt supply circuit with the vehicle in drive. In all test vehicles, the ECM did not set a DTC and the engine speed increased rapidly to full throttle.

    Dan - Owner
    http://www.Hi-TecDesigns.com

    RE: Recent Engineering Debacles

    Aha, so Toyota can now blame the car owners for failing to adequately maintain their cars, resulting in these shorts that caused the sudden accelerations!  Whew, got out of that one!  And, look Ma, we saved hundreds of millions of dollars by not having to recode the safety routines!

    TTFN

    FAQ731-376: Eng-Tips.com Forum Policies

    RE: Recent Engineering Debacles

    The link posted was just another report on the same subject and it was from CBS.  My reference to ABC was from their news broadcast heard several times and it was they that reported that Toyota has also replicated the test first reported on the day before.  The professor who devised and performed the test with an ABC reporter, Brian Wilson, on board has or will testify before Congress.
    Toyota has backed off, weaseling, the statement that the problem was absolutely not electrical/electronic, this is from testimony before Congress.  

    It was Brian Wilson who first broke the story of the sudden acceleration excursions.  

    Could it be that the Toyota people were so cock sure that anything that malfunctioned in their control system would generate an error code.  No codes, no problem.  

    RE: Recent Engineering Debacles

    If multiple accelleration sensors exist, then one could suggest that additional diagnostics to detect the short described to be "design development" as opposed to a design flaw.  However additional diagnostics to detect shorted Accelerator Pedal Position sensors sounds like an improvement that should be made immediately.

    RE: Recent Engineering Debacles

    Japan has had, for so long, a solid reputative in reliability and process improvement that they've developed superiority complex about this, not that they didn't have one to start with.

    I recall that Sony, back in the 80's, was doing silicon foundry work, and a customer had a yield crash that went unsolved for months, until Sony's engineers from Japan came to the US and verified that the crash was real.

    Hitachi was similarly cocky about their processing.  While US manufacturers routinely had 4 or 5 test chips per wafer, Hitachi felt that it was a waste of perfectly good silicon, and had no test patterns whatsoever on their older products.  At that time, such confidence was indeed justified, as their parts yielded better than any of our own parts, even though we had no idea what the ideal process parameters were supposed to be for those parts.  We had has Hitachi what to set the process to, and they replied, "Don't worry, just run the wafers."  

    That was the heyday and legacy of Deming's work in Japan.  It's likely that they've lapsed on their laurels a bit too much.

    TTFN

    FAQ731-376: Eng-Tips.com Forum Policies

    RE: Recent Engineering Debacles

    An engineer with NASA tells me that the space station software applications from Japan are flawless in stark contrast to the western software.

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