An Experimental Study of Composite Columns Filled with Eucalyptus nitens Timber under Axial Compression

Eucalyptus nitens (E. nitens) has been much used for producing paper but also shows promise for structural applications. In this study, static compressive tests were undertaken to examine its suitability to be used in an innovative composite column. The composite column was comprised of a rectangular steel tube with E. nitens timber infill. The nonlinear compressive behaviour of the composite column filled with E. nitens wood for both dry and wet conditions was examined. The same tests on rectangular steel tubes and bare dry and wet E. nitens samples were also undertaken as a comparison. For samples with different conditions, the ultimate capacity was evaluated and the effect of each condition on the compressive behaviour of the composite column was clarified. The steel tubes showed greater ductile behaviour, and more ductility was found in the wet samples. The steel tubes with E. nitens timber infill samples exhibited a greater linear elastic range connected with higher maximum loads, while the bare timber samples could support only lower maximum loads. The results from this research were promising for the use of rectangular steel tubes with E. nitens timber infill in structural applications.