ENGINEER'S PERSPECTIVE OF THE BIG DIG FAILURES
This was sent to me by Keith Steurer, a Iowan for Romney. I met Keith while in Iowa, a very nice guy. Keith guest-blogs on Iowans for Romney and emailed me a copy of this. With his permission I have gone ahead and posted this.
ENGINEER'S PERSPECTIVE OF THE BIG DIG FAILURES
I am a structural engineer, licensed in 2 states, with 6 years design experience. The recent BIG DIG failures have been of great interest to me and to my co-workers. There is an unwritten rule in engineering, that when things go wrong, you read up on them as much as possible to make sure that it never happens again. There have been several historic engineering failures throughout history. Usually, the only thing that makes them historic the loss of life (IE Hyatt Regency catwalk failure), or the freak factor (Tacoma Narrows Bridge failure). The BIG DIG has both of these factors because there has unfortunately been a life ;lost due to the failure, and this project is freakishly expensive, large, and encompassing.
I have read up much about the BIG DIG tunnel ceiling failure, and how it happened. Basically, there were concrete panels, hung above the traffic with epoxy anchors. We use epoxy anchors all the time in construction because they are versatile, easy to install, and take very little training or expertise to install. HOWEVER, great caution should be used when installing them in a ceiling. This is known throughout the engineering world. They only perform correctly if installed correctly. As a designer, I actually have a rule that I never use epoxy anchors in a ceiling. WHY? Because the epoxy doesn't tend to fill the hole completely, and while the epoxy is setting it can run out of the hole. Manufacturers of the epoxy anchors have plenty of testing to show that they are safe for use in ceilings, but sky diving is also technically safe, and I still do not take that risk either. Also the panel fastening system was not redundant. Meaning, if one fastener fails, the remaining will not have the capacity to support the system, and they will all fail, one at a time. They reported that many of the anchors were not tightened adequately either. This is a simple installation problem. Unfortunately, these anchors are most often installed by the least trained, least responsible laborers on a job site, and are rarely tested in place to verify correct installation. I deal with this on my own projects.
I read a great article in the Engineering News Record. See link : http://enr.ecnext.com/free-scripts/comsite2.pl?page=enr_document&article=netrar060731
This is written for engineers, by engineers. I feel it is very honest in exposing the back and forth of who was taking charge of the project and inspections, and what needs to be done. Governor Romney is quoted as having questioned all 1,150 epoxy anchors in that particular tunnel, which is exactly what any trained inspector would do. Unfortunately, it appears as if the previous inspectors (if any), and others involved in this massive project have too much money at stake, too much bribing, and corner cutting going on to take reasonable charge of their own work. No one likes to be the guy that shuts down a construction site to have things tested, but someone has to do it for this level of risk. I am impressed with Romney's resolve to ensure every part of the project is safe, not just the immediate areas of concern. He has taken on much larger challenges that this, so I am sure he will not fail the people of Massachusetts. I look forward to seeing what type of system they come up with to replace the anchors, and hopefully this will never happen again. Are you listening, fellow engineers???
Keith Steurer, PE, LEED AP
Thanks Keith! Very informative
ENGINEER'S PERSPECTIVE OF THE BIG DIG FAILURES
I am a structural engineer, licensed in 2 states, with 6 years design experience. The recent BIG DIG failures have been of great interest to me and to my co-workers. There is an unwritten rule in engineering, that when things go wrong, you read up on them as much as possible to make sure that it never happens again. There have been several historic engineering failures throughout history. Usually, the only thing that makes them historic the loss of life (IE Hyatt Regency catwalk failure), or the freak factor (Tacoma Narrows Bridge failure). The BIG DIG has both of these factors because there has unfortunately been a life ;lost due to the failure, and this project is freakishly expensive, large, and encompassing.
I have read up much about the BIG DIG tunnel ceiling failure, and how it happened. Basically, there were concrete panels, hung above the traffic with epoxy anchors. We use epoxy anchors all the time in construction because they are versatile, easy to install, and take very little training or expertise to install. HOWEVER, great caution should be used when installing them in a ceiling. This is known throughout the engineering world. They only perform correctly if installed correctly. As a designer, I actually have a rule that I never use epoxy anchors in a ceiling. WHY? Because the epoxy doesn't tend to fill the hole completely, and while the epoxy is setting it can run out of the hole. Manufacturers of the epoxy anchors have plenty of testing to show that they are safe for use in ceilings, but sky diving is also technically safe, and I still do not take that risk either. Also the panel fastening system was not redundant. Meaning, if one fastener fails, the remaining will not have the capacity to support the system, and they will all fail, one at a time. They reported that many of the anchors were not tightened adequately either. This is a simple installation problem. Unfortunately, these anchors are most often installed by the least trained, least responsible laborers on a job site, and are rarely tested in place to verify correct installation. I deal with this on my own projects.
I read a great article in the Engineering News Record. See link : http://enr.ecnext.com/free-scripts/comsite2.pl?page=enr_document&article=netrar060731
This is written for engineers, by engineers. I feel it is very honest in exposing the back and forth of who was taking charge of the project and inspections, and what needs to be done. Governor Romney is quoted as having questioned all 1,150 epoxy anchors in that particular tunnel, which is exactly what any trained inspector would do. Unfortunately, it appears as if the previous inspectors (if any), and others involved in this massive project have too much money at stake, too much bribing, and corner cutting going on to take reasonable charge of their own work. No one likes to be the guy that shuts down a construction site to have things tested, but someone has to do it for this level of risk. I am impressed with Romney's resolve to ensure every part of the project is safe, not just the immediate areas of concern. He has taken on much larger challenges that this, so I am sure he will not fail the people of Massachusetts. I look forward to seeing what type of system they come up with to replace the anchors, and hopefully this will never happen again. Are you listening, fellow engineers???
Keith Steurer, PE, LEED AP
Thanks Keith! Very informative
posted by jason at Tuesday, August 01, 2006
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