NIST heated the floor beams, but not the slab. Since concrete expands at 85% the rate of steel, leaving this expansion out of the calculations of the failure of the shear studs is fraudulent.
By Chris Sarns
Architects and Engineers for 911/Truth
Part 2 (below) was originally published on June 10, 2013.
NIST used numerous unscientific methods and fraudulent inputs to get the key girder to fail in its computer simulation.
For example, NIST arbitrarily added 10% to the temperature results of its fire dynamics simulation (FDS).
“Case A used the temperature data as obtained from the FDS simulation. Case B increased the Case A gas temperatures by 10 percent.” — NCSTAR 1A, page 32 [PDF page 74]
“[O]nly the fire-induced damage produced by Case B temperatures was carried forward as the initial condition for the building collapse analysis.” — NCSTAR 1A, page 36 [PDF page 78]
To get the shear studs on the floor beams to fail, NIST had to assume high steel temperatures. It applied the heat in 1½ seconds over the entire northeast part of Floor 13. This faulty method of calculating temperatures, though, does not allow for the reality of heat dispersal or for the inevitable beam sagging.
Interestingly, NIST’s model heated the floor beams but not the concrete slab. Since concrete expands at 85% the rate of steel, leaving this expansion out of the calculations of the shear studs failure is fraudulent.
“The girder and beam temperatures were assumed to be 500° C and 600° C, respectively, and the slab was assumed to remain unheated.” — NCSTAR 1-9, Vol. 1, page 349 [PDF page 393]
“Ramping of the temperatures for the beams and the girder then commenced at 1.1 s, leveling off at temperatures of 600° C for the beams and 500° C for the girder at 2.6 s. These temperature histories were prescribed uniformly for all nodes of the beams and the girder, respectively.” — NCSTAR 1-9, Vol. 1, page 352 [PDF page 396]
“The first failures observed were of the shear studs, which were produced by axial expansion of the floor beams, and which began to occur at fairly low beam temperature of 103° C. . . . When the beam temperatures had reached 300° C, all but three shear studs in the model had failed due to axial expansion of the beams, leaving the top flanges of the beams essentially unrestrained laterally.” — NCSTAR 1-9, Vol. 1, page 352 [PDF page 396]
“This analysis demonstrated possible failure mechanisms that were used to develop the leading collapse hypothesis further. The failure modes in this model were incorporated into the 16-story ANSYS and 47-story LS-DYNA analyses.” — NCSTAR 1-9, Vol. 1, page 353 [PDF page 397]