EUROCODE 5 - BASED RELIABILITY ANALYSIS OF AXIALLY LOADED SOLID TIMBER COLUMNS USING SELECTED NIGERIAN TIMBER SPECIES
EUROCODE 5 - BASED RELIABILITY ANALYSIS OF AXIALLY LOADED SOLID TIMBER COLUMNS USING SELECTED NIGERIAN TIMBER SPECIES
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Date
2014-04
Authors
MAMMAN, Abubakar
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Abstract
In this research work, a reliability analysis was carried on three Nigerian timber specie namely:
Mitragyna ciliata (Abura), Afromosia elata (Afromosia) and Confusa grandiflora (Berlinia) after
classifying the species to international strength classification system using EN 338 (2003) with the
aid of statistical package Easyfit (2010) .This was done after establishing the physical and
mechanical properties in the laboratory using ASTM D193 (2000) and EN408 (2003). Mitragyna
ciliata was assigned to strength Class of C18 with minimum characteristic values of density,
strength and stiffness properties of 466 kg/m2, 80.2 N/mm2 and 9.21 kN/mm2 respectively as
contained in EN 338 (2003). Afromosia elata and Confusa grandiflora were assigned to strength
Class D30 with characteristic properties of density, strength and stiffness of 480 kg/m2, 131.2
N/mm2 and 11.85 kN/mm2 for Afromosia elata and 462 kg/m3, 89.2N/mm2, 12.74 kN/mm2 for
Confusa grandiflora. The reliability analysis carried on the slender timber column was undertaken
to check for six failure modes namely: compression, bending, flexural buckling, lateral torsional
buckling, and carrying capacity of dowel connection and shear stress capacity of the joint failure
modes. Critical mode of failure from the first four failure modes was found to be lateral torsional
buckling mode of failure with the lowest β-value of 2.87 for Mitragyna ciliata, 3.4 for Afromosia
elata and 3.52 for Confusa grandiflora, at a load ratio of 0.8 for compression and bending failure ,
0.2 for flexural and lateral torsional buckling failure modes. Critical values of safety index
obtained are lower than the code value of 3.8 (BS EN 1990:2002). While, the critical mode of
failure for dowel connection was found to be in the carrying capacity of Dowel, with safety value
of 1.69 at a load ratio of 0.8, also lower than the code value of 3.8 (BS EN 1990:2002).
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE
STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA
IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE
AWARD OF MASTER DEGREE
IN CIVIL ENGINEERING
DEPARTMENT OF CIVIL ENGINEERING
FACULTY OF ENGINEERING
AHMADU BELLO UNIVERSITY, ZARIA
APRIL, 2014
Keywords
EUROCODE,, RELIABILITY,, ANALYSIS,, LOADED SOLID,, TIMBER SPECIES