Once collapse had initiated, the total top-to-bottom progression of each tower has been demonstrated by end-to-end structural modeling.

The claim asserts an end-to-end model exists; the agency states propagation was explained without that modeling and offers a capacity argument instead (SEP-E014). The verdict grades the existence of the model, not the physics.

The investigating agency explicitly acknowledges that once collapse initiated, the downward propagation was explained using a static floor-capacity argument. No full-scale dynamic structural modeling of the complete top-to-bottom progression has ever been published.

The investigating agency explicitly stated that the downward propagation was "readily explained without the same complexity of modeling," relying instead on a floor-capacity mathematical argument. No full end-to-end simulation of the total progression to the ground was published by NIST or anyone else. The strongest opposing consideration is that peer-reviewed mechanics literature argues the energy balance strongly favors total collapse once a dozen floors drop, making high-fidelity simulation unnecessary for understanding the physics.

NIST’s own FAQ explicitly states that once collapse began, its progression was “readily explained without the same complexity of modeling,” and supports this with simple capacity calculations, confirming that no end‑to‑end, high‑fidelity progressive‑collapse simulation for either tower was undertaken. While mechanics papers argue that once a sufficient mass begins to descend gravitational progression is inevitable, this does not change the fact that a full‑tower numerical demonstration “has been” modeled is directly at odds with the record.

NIST’s own FAQ states that once collapse initiated, it did not model the entire progression but instead relied on a capacity argument that propagation was “readily explained without the same complexity of modeling.” No other source in the dossier describes a complete, high‑fidelity, top‑to‑bottom structural simulation of either tower’s collapse, so the assertion that such end‑to‑end modeling has been done is directly at odds with the record.

NIST's towers FAQ states that once collapse had begun, "the propagation of the collapse was readily explained without the same complexity of modeling," supporting that judgment with a floor-capacity comparison (11 additional floors if applied gradually, 6 if suddenly) rather than a simulation. The claim as worded asserts that end-to-end structural modeling of the total progression exists; the investigating agency says it does not. The strongest opposing consideration is that this is a verdict about the existence of a model, not about whether gravity suffices: order-of-magnitude capacity arguments may still be physically adequate even though they are not a demonstration.

NIST modeled initiation and stated that propagation "was readily explained without the same complexity of modeling," supporting that judgment with a floor-capacity comparison — eleven floors if applied gradually, six if suddenly — rather than a simulation. The claim as worded asserts that an end-to-end model of total progression has been published; the agency's own FAQ says it has not. The strongest opposing consideration is that order-of-magnitude mechanics arguments hold that once a dozen-plus stories drop one storey, arrest is not plausible, so full simulation may be unnecessary to the physics even though it is necessary to the auditability question.

The agency itself states that propagation "was readily explained without the same complexity of modeling," supporting that with a capacity argument rather than a simulation. The claim as worded — that end-to-end modeling exists — is contradicted by the record. The strongest opposing consideration is that order-of-magnitude analyses in the mechanics literature argue the energy balance is not close, so full simulation may be physically unnecessary even though it would answer the auditability question.

The claim asserts that total progression "has been demonstrated by end-to-end structural modeling," and the agency's own FAQ negates it: propagation "was readily explained without the same complexity of modeling," supported by a floor-capacity comparison (six additional floors under sudden load) rather than any simulation. As a claim about what exists in the literature, the record directly contradicts it. The strongest opposing consideration is that order-of-magnitude energy analyses in the peer-reviewed mechanics literature argue arrest was implausible once a dozen-plus stories dropped — so the physics judgment may be sound — but a defensible engineering judgment is not the end-to-end demonstration the claim asserts.

The claim as worded asserts the existence of an end-to-end structural demonstration, and the investigating agency states directly that propagation "was readily explained without the same complexity of modeling," supporting its position with a floor-capacity comparison rather than a simulation. No published work in this ledger fills the gap. The strongest opposing consideration is that this is a statement about what exists rather than about the physics: order-of-magnitude mechanics arguments hold that arrest is implausible once a dozen-plus stories drop one storey, so the missing model may be unnecessary to answer the physical question even while the auditability gap remains real.

The claim asserts the existence of an end-to-end demonstration, and the agency states directly that propagation was "readily explained without the same complexity of modeling," substituting a floor-capacity argument for a simulation (SEP-E014). That is a defensible engineering judgment and not an end-to-end model, so the claim as worded fails. The strongest opposing consideration is that this is a universal negative about the literature and the ledger cannot exhaustively survey it — the Bažant records are cited only for what they are, with no text obtained. Nothing here implies the physics is wrong; only that the auditable demonstration does not exist.

The claim asserts an end-to-end model exists; the agency states propagation was explained without that modeling. The verdict grades the existence of the model, not the physics.