RELIABILITY-BASED ANALYSIS OF COMPOSITE SOLID SLENDER TIMBER COLUMNS WITH ALUMINIUM LAMINATES USING SELECTED NIGERIAN TIMBER SPECIES

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Department of Engineering

ABSTRACT
Four timber species (Strombosia pustulata, Macrocarpa biquertii, Entandrophragma cylindricum and Nauclea diderichii) were laminated with aluminium sheets of varying thicknesses.Axial and flexural loads were applied to the composite columns to determine their behaviour under such loadings. Finite element analysis was carried out in Abaqus/CAE 6.10 (2010) and the reliability analysis was carried out using the First Order Reliability Analysis (FORM) in MATLAB (2007) on the laminated timber columns. The results for finite element analysis show the effect of the thickness of Aluminium laminates on the strength capacity of timber columns whereby deflection reduced from 3.28×10-2mm for timber column without laminate to 2.96×10-2mm with the introduction of 20mm aluminium laminate in the x-axis. Similarly, the deflection reduced from 5.18×10-2mm to 1.18×10-2mm in the y-axis, and 5.45mm to 1.093mm in the z-axis for the timber (Strombosia pustulata specie) column that is fixed-free end restraint condition. For the reliability analysis, bending, buckling and flexural buckling failure modes were considered. The results for compression mode of failure show that the column is safewith safety index values of 4.3 and 9.68 for load parameters and dead-to-live load parameters respectively without laminates. The study shows that the most critical failure mode for the column is flexural buckling and hence isnot safe for imposed loads that are greater than 20kN but made safe with the use of aluminium laminate of 8mm.