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| Home Front: WoT |
| Timothy McVeigh, Terry Nichols and Ramzi Yousef (Part 12, Final) |
| 2004-04-23 |
| Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11 All the following is from an article written by William F. Jasper and published by The New American in 1997. .... Led by Brigadier General Benton K. Partin (USAF, ret.), former director of the Air Force Armament Technology Laboratory and one of the world’s premier explosives and ordnance authorities, critics have argued compellingly that the blast wave from the ANFO [ammonium nitrate/fuel oil] truck bomb was totally inadequate to cause the collapse of the massive, steel-reinforced concrete columns of the federal building in Oklahoma City. This fact ... points inescapably to the conclusion that additional demolition charges had to have been placed on columns inside the building. .... The new Eglin [Air Force Base] blast study convincingly proves the fundamental points set forth by General Partin: That air blast is an inefficient mechanism against hardened, reinforced concrete structures, and that "the pattern of damage [to the Murrah Building] would have been technically impossible without supplementing demolition charges." Entitled Case Study Relating Blast Effects to the Events of April 19, 1995 Alfred P. Murrah Federal Building, Oklahoma City, Oklahoma, (hereafter referred to as the Eglin Blast Effects Study, or EBES), the 56-page report includes photographs and data from the Eglin blast tests, as well as extensive technical analysis of those tests ..... As General Partin has taken great pains to emphasize, the inefficiency of a blast wave through air is dramatic -- particularly outdoors, where the blast energy is dissipated in all directions -- with its pressure and destructive force falling off more rapidly than an inverse function of the distance cubed (distance expressed in radius units). This means that the blast wave from an explosive device which yields a maximum blast pressure of one-and-a-half million pounds per square inch at the center of the device will have dropped off to under 200 pounds per square inch by the time it has traveled 20 radii. This makes air blast alone very ineffective against hardened concrete structures, such as heavy, steel-reinforced columns. .... Accordingly, the EBES found: "A limited area of the third and fourth floors of the Murrah Federal Building immediately adjacent to the position of the Ryder truck would be affected. .... the EBES conclusions have a built-in margin of error that, if anything, overstate the extent of damage to be expected at the Murrah Building. Moreover, the computations for the Ryder truck bomb also are overly generous. "Because ANFO is also a low-energy explosive (approximately 30% that of TNT) and due to the inherent inefficiency of eight barrels forming the explosive assembly [according to the government’s estimates], it is doubtful that the device produced blast pressures close to the calculated maximum potential blast pressure," the study asserts. "This being the case, it is doubtful that the radius of damage even approached the 42.37 foot range as calculated herein." Finally, the EBES concludes: [quote] Due to these conditions, it is impossible to ascribe the damage that occurred on April 19, 1995 to a single truck bomb containing 4,800 lbs. of ANFO. In fact, the maximum predicted damage to the floor panels of the Murrah Federal Building is equal to approximately 1% of the total floor area of the building. Furthermore, due to the lack of symmetrical damage pattern at the Murrah Building, it would be inconsistent with the results of the ETS test [number] one to state that all of the damage to the Murrah Building is the result of the truck bomb. The damage to the Murrah Federal Building is consistent with damage resulting from mechanically coupled devices placed locally within the structure.... It must be concluded that the damage at the Murrah Federal Building is not the result of the truck bomb itself, but rather due to other factors such as locally placed charges within the building itself.... The procedures used to cause the damage to the Murrah Building are therefore more involved and complex than simply parking a truck and leaving.... [unquote] Mike Smith, a civil engineer in Cartersville, Georgia commissioned to review the Eglin Blast Effects Study, states: "The results of the Blast Effect Test One on the Eglin Test Structure present strong evidence that a single Ammonium Nitrate and Fuel Oil device of approximately 4800 lbs. placed inside a truck could not have caused the damage to the Murrah federal Building experienced on April 19, 1995. Even assuming that the building had structural deficiencies and that the ANFO device was constructed with racing fuel, the air-coupled blast produced from this 4800 lb. device would not have damaged the columns and beams of the Murrah Building enough to produce a catastrophic failure." Robert Frias, president of Frias Engineering of Arlington, Texas, after examining the EBES, concluded: "The Murrah Building would still be standing and the upper floors would be intact had the truck loaded with explosives been the only culprit. .... Explosives had to have been placed near, or on, the structural columns inside the building to cause the collapse that occurred to the Murrah Building." Likewise, Alvin Norberg, a licensed professional engineer ... writes that evidence from the ETS data "verifies that the severe structural damage to the Murrah Building was not caused by a truck bomb outside the building," and that "the collapse of the Murrah Federal Building was the result of ’mechanically coupled devices’ (bombs) placed locally within the structure adjacent to the critical columns." .... |
| Posted by:Mike Sylwester |
| #10 What I'm more interested in is the failure of the columns. Pete, from what I can remember on the program examining the failure of the Murrah building, the columns didn't fail. The blast wave pushed the cross members sitting on the column up and sideways, the center of the blast being lower than the joint. That kicked the crossmember off the column. The upper floor supports rested on this crossmember and when it dropped they dropped with it. The floor panels, cross members and other columns mostly stayed intact, the joints between them failed. I seem to remember them saying because this was a low velocity pressure wave, it had more of a long slow push on the cross member and more load was transmitted to the joint causing it to fail. Again, I'm doing this from memory, but it made perfect sense at the time I viewed it. |
| Posted by: Steve 2004-04-23 2:57:35 PM |
| #9 "55.2 kPa (8 PSI) overpressure wave is considered to be highly lethal and can collapse building floors. According to paragraph 3 above, the blast wave at OK City was 200 PSI when it intersected the Murrah building facade. This is in fact greater than the overpressure needed to topple unreinforced structures (e.g. wood stud construction)." I have no doubt that the McVeigh truck bomb could have knocked down the walls and ripped out the floors. What I'm more interested in is the failure of the columns. Specifically, the columns Partin designates as 'B3' and 'A7'. You'd need about 3,300 psi to knock fail one of these steel-reinforced concrete columns, no? And that's a conservative number, assuming bad concrete. (There was a brief concrete discussion at Rantburg last year sometime - I think it had to do with the three gorges dam.) It doesn't help that I'm a technical ignoramus while trying to sort through this stuff. I hadn't considered the reflections or a design flaw - thanks for that information. |
| Posted by: Pete Stanley 2004-04-23 1:56:18 PM |
| #8 I have to say that the removal of the explosive argument (you've convinced me) makes most of my previous arguments less compelling for me. Anyone else who wants to research all this should begin and end with the book American Terrorist, which is basically McVeigh's statement that he did it alone (with some coerced help with Nichols). In my series of articles I tried to develop the idea that perhaps McVeigh himself did not know some significant factors that Nichols introduced into the events. If McVeigh's truck did indeed suffice to blow up the building, then those other factors are rather irrelavant. Maybe Nichols did inform a "Yousef group" that then showed up to watch, but those watchers were probably not involved actively. There are many, many eyewitness reports of other people and other trucks, but they don't stand up very well against American Terrorist. Anyway, I did want to develop this idea, and I was looking for a forum, and when I found Rantburg, I felt this was the perfect place for me to be. |
| Posted by: Mike Sylwester 2004-04-23 1:29:13 PM |
| #7 Hi Mike: I liked the article. I'd just leave the explosive conspiracy stuff out. It just doesn't check out. I'd read the link I posted. It's not just the blast wave. The ground transmits energy too and blast waves can be reflected and combine and subtract for surreal effects. Nobel's brother was standing next to him during an accidental explosion. The brother was killed. Nobel didn't have a scratch. He was standing in a dead spot. |
| Posted by: 11A5S 2004-04-23 11:43:20 AM |
| #6 Speaking as a netizen of Rantburg, Mike S. I also appreciate all the time and effort you've put into this series. |
| Posted by: Seafarious 2004-04-23 11:42:49 AM |
| #5 Speaking as an associate editor here, Mike, you've done a great job on this, and I appreciate it. |
| Posted by: Steve White 2004-04-23 11:38:44 AM |
| #4 Watched one of those engineering disaster shows on Learning Channel a few years back. They did a indepth examination of this collapse. Found that the Murrah Building had a design flaw. Structure depended on gravity to keep load from upper floors straight down on the cross members.The structure didn't have a strong enough joint holding columns to cross members. The blast kicked cross members on first floor off the vertical column, then gravity brought the upper floors down like a house of cards. |
| Posted by: Steve 2004-04-23 9:51:12 AM |
| #3 11A58, I appreciate your knowledge and information. Before I posted this I did view the photographs of the Saudi building with this comparison in mind. I had the impresssion that the Saudi buildings were not as solidly built as the Murrah building. I wrote and posted these articles in order to get useful feedback such as yours. I also appreciate the forum that Rantburg provided. I don't intend to write any more on this subject. |
| Posted by: Mike Sylwester 2004-04-23 9:49:35 AM |
| #2 BTW, here are the effects of overpressure waves from explosions: A 55.2 kPa (8 PSI) overpressure wave is considered to be highly lethal and can collapse building floors. According to paragraph 3 above, the blast wave at OK City was 200 PSI when it intersected the Murrah building facade. This is in fact greater than the overpressure needed to topple unreinforced structures (e.g. wood stud construction). |
| Posted by: 11A5S 2004-04-23 9:36:59 AM |
| #1 Another one of my pet peeves. Go back to the pictures of the Saudi building boomed the other day. Vertical supports are buckled and floors are partially collapsed. These were clearly "air coupled" explosive effects. Just because a guy is a licensed civil-structual engineer or has imploded buildings, doesn't make him an expert in the effects of several thousand pounds of HE 20 or 30 feet outside an office building. I would instead look to the after WWII bomb damage surveys for empirical data based on a large number of samples. |
| Posted by: 11A5S 2004-04-23 9:13:37 AM |