| Summary: | During March of 2020 a large-span sports arena, Tarfala hall, built 2015, collapsed in northern Sweden. The main load-bearing girders with a 54 m span, were high and slender glulam beams supported underneath by a cable system via vertical struts. Investigations concluded that the failure was initiated by lateral buckling of the struts and slender beam, in spite of lateral stabilization by a corrugated steel roof at the top edge of the beam and by glulam rods at the lower end of the strut where the cable system was attached. The nailed joint between strut and main glulam beam was not stiff enough to prevent buckling. Following the collapse, the Swedish accident investigation board urged all municipalities to review similar structures before allowing people inside again. This has led to a sudden and urgent need for a better understanding of this type of structure. In this study a nailed connection similar to that used in the arena, though in smaller scale, was tested under combined bending and axial loading. The biaxial testing simulates vertical loading in the strut combined with out of plane loading created by second order effects. One objective was to investigate how the axial load acting perpendicular to grain on one side of the joint affects the bending stiffness and capacity of the nailed joint. In the biaxial testing the vertical load was prescribed to 75 %, 50 % respectively 25 % of the mean failure load when tested in pure compression. It was found that the out of plane stiffness of the joint is reduced when vertical loading is at high levels. This effect may have contributed to the collapse of the arena. I mars 2020 rasade Tarfalahallen i Kiruna. Idrottshallens takkonstruktion bestod av långa underspända limträbalkar upplagda på limträpelare. Balkarna var underspända med hjälp av två trycksträvor som stöttades med dragband av stål och anslutningen mellan trycksträvorna och balken bestod av spikförband. Statens Haverikommission (SHK) har en pågående utredning kring raset, och har hittills bland annat ...
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