The Journal of 9/11 Studies has recently published a paper entitled “Momentum Transfer Analysis of the Collapse of the Upper Storeys of WTC 1” by Gordon Ross. The Journal paper presents an alternative approach to an earlier treatment of this topic by F. R. Greening: “Energy Transfer in the WTC Collapse” (available in PDF format at 911myths.com). The paper by Ross claims to show that a simple gravitationally driven collapse of the upper section of WTC 1 would have been arrested after the first impact. By contrast, Greening’s previously mentioned paper concludes that a self-sustaining progressive collapse was physically possible for WTC 1 & 2.
I intend to show that Mr. Ross’ article is incorrect in at least four important ways.
- An error in the calculation of the kinetic energy of the falling section after the first impact.
- An over-estimation of the energy required to pulverize the WTC 1 concrete.
- The argument that the initial elastic deflection would propagate 24 storeys
below the impact floor.
- The use of a safety factor of 4 in the calculation of the elastic strain energy.