FIG.4: The above graph[10]comparesDavid Chandler’s measurement[9] of the velocity of the roofline of WTC 1 with Bažant’s erroneous calculation [11] and with Szamboti and Johns’ calculation using corrected input values for mass, acceleration through the first story, conservation of momentum, and plastic moment (the maximum bending moment a structural section can withstand). The calculations show that—in the absence of explosives—the upper section of WTC 1 would have arrested after falling for two stories (Source: Ref. [10]).