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Light steel-frame building systems are becoming more prevalent in commercial, industrial and residential construction in New Zealand. Tested fire resistance ratings are generally available for non-load-bearing systems, but not for load-bearing applications. This study investigates the performance of load-bearing light steel-frame systems exposed to fire. Methods are presented for calculating the reduction of steel strength and stiffness at elevated temperatures, and for predicting the deflections resulting from temperature gradients and P-A effects. Heat transfer modelling by computer is used to predict steel framing temperatures for systems exposed to the standard IS0 834 timetemperature curve and real fires. Three full-scale furnace tests were camed out to evaluate analytical predictions. A design procedure is proposed.

If dark matter is efficiently captured by a planet, energy released in its annihilation can exceed that planet's total heat output. Building on prior work, we treat Earth's composition and dark matter capture in detail and present improved limits on dark matter-nucleon scattering cross sections for dark matter masses ranging from 0.1 to 10 10 GeV. We also extend Earth limits by applying the same treatment to Mars. The scope of dark matter models considered is expanded to include spin-dependent nuclear interactions including isospin-independent, proton only, and neutron only interactions. We find that Earth and Mars heating bounds are alleviated for dark matter s-wave self-annihilation cross sections 10 −37 cm 2 .