How much of a floor-vibration penalty does the subfloor's T-beam action recover?

research/house-composite

How much of a floor-vibration penalty does the subfloor's T-beam action recover? Gamma-method partial-composite stiffness on house-vibration: at a 15 Hz limit a 2x10 at 16 in grows from 12 ft 6 in to 13 ft 2 in–14 ft 6 in, depending on two assumed inputs (connection efficiency and panel modulus). Stylised.

6 tests

What it found

The subfloor modelled as a partial flange of a T-beam by the gamma method (rederived from the parallel-axis theorem and tested against an independent transformed-section calculation), added to the frequency check of house-vibration for a 2x10 SPF No. 2 joist at 16 in. The result depends on two assumed, unsourced inputs, the connection efficiency γ and the panel modulus. At a panel modulus of 0.5 million psi the 15 ft first-mode frequency rises from 10.5 Hz to 12.6 Hz at γ 0.5 and 14.0 Hz at γ 1, and under a 15 Hz limit the span grows from 12 ft 6 in to 13 ft 2 in–14 ft 6 in. Strength checks stay joist-alone; live-load mass is left out, so gains are optimistic. Stylised, not validated against a measured floor, not a design.

A figure from its own output

Figure produced by research/house-composite: span_vs_frequency — house-composite/experiments/span_vs_frequency.svg, written by the project's own experiment code.

Paper, code and results

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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.