Strength properties of selected Uganda timbers

Zziwa, Ahamada; Ziraba, Y. N.; Mwakali, J.A.

doi:10.1179/002032010x12759166444887

Cited by 8 publications

(9 citation statements)

References 12 publications

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“…The mean values of basic density, compressive strength parallel to grain, MOE, and MOR the whole trees were 0.43 g cm -3 , 42.4 MPa, 8.92 GPa, and 97.3 MPa for A. mangium, 0.33 g cm -3 , 30.6 MPa, 6.84 GPa, and 72.7 MPa for M. eminii, and 0.44 g cm -3 , 39.7 MPa, 8.36 GPa, and 90.3 MPa for M. azedarach (Table 3). With a few exceptions, the mean values of wood properties obtained in the present study were in the range of the values reported by previous researchers (Table 4, Chowdhury et al 2009;Zziwa et al 2010;Makino et al 2012;Jusoh et al 2014;Duong and Matsumura 2018a, b;Duong et al 2019).…”

Section: Wood Propertiessupporting

confidence: 82%

“…A previous study found a positive correlation between wood density and compressive strength in A. mangium (Makino et al 2012) and A. auriculiformis (Chowdhury et al 2009). In addition, wood density has also been found to be correlated with the MOE and MOR in M. azedarach (Duong and Matsumura 2018a) and Uganda timber species (Zziwa et al 2010). Another study found a high positive correlation between the MOE and MOR (r 0.81) in M. azedarach (Duong and Matsumura 2018a).…”

Section: Relationships Between Air-dry Density and Wood Propertiesmentioning

confidence: 96%

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Wood properties and simulated modulus of elasticity of glulam in three fast-growing tree species grown in community forests in Yogyakarta, Java Island, Indonesia

Ngadianto

Ishiguri

Nezu

et al. 2020

Tropics

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Community forests in Indonesia are important suppliers of wood resources for the wood industry. In the present study, stress-wave velocity of stems, log characteristics (taper, green density, and dynamic Young s modulus), and wood properties (basic density, compressive strength parallel to grain, modulus of elasticity [MOE], and modulus of rupture [MOR]) were investigated for three fast-growing tree species grown in community forests in Indonesia: Acacia mangium Willd., Maesopsis eminii Engl., and Melia azedarach L. Based on the bending properties, the MOE values of laminae (30 150 mm in cross-section) and glulam (six layers, 90 150 mm in cross-section) were simulated. The mean values of simulated MOE in the laminae were 8.93, 6.82, and 8.63 GPa for A. mangium, M. eminii, and M. azedarach, respectively. When the laminae from a species were randomly laminated, the simulated MOE values of glulam were 8.94, 6.82, and 8.66 GPa for A. mangium, M. eminii, and M. azedarach, respectively. When laminae with a high, medium, and low MOE were laminated at outer, middle, and inner layers of glulam, respectively, the simulated MOE values of glulam increased by about 5 % to 15 % compared to the values of a randomly laminated one. It is concluded that glulam with a high MOE can be produced from fast-growing tree species grown in community forests in Indonesia.

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Section: Wood Propertiessupporting

confidence: 82%

Section: Relationships Between Air-dry Density and Wood Propertiesmentioning

confidence: 96%

Wood properties and simulated modulus of elasticity of glulam in three fast-growing tree species grown in community forests in Yogyakarta, Java Island, Indonesia

Ngadianto

Ishiguri

Nezu

et al. 2020

Tropics

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“…Where:F12 = the modulus of rupture at 12% moisture content, W = the moisture content at the time of testing, Fw = the modulus of rupture at the moisture content at the time of testing, 𝛼 = the correction factor for moisture content. 𝛼 was adapted from [10] as 0.04.…”

Section: 𝐹 12 = 𝐹 𝑤 (1 + 𝛼(𝑊 − 12)mentioning

confidence: 99%

Characterisation and grading of four selected timber species grown in Nigeria in accordance with Bs 5268

et al. 2021

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This study presents a development of strength classes for Vitex doniana, Diospyros mespliformis, Parkia biglobosa and Isoberlinia doka, northern Nigeria timber species in accordance with BS 5268-2 (2002) and NCP 2 (1973). The specimens for the experimental measurements were obtained from timber-sheds in Zaria, Kaduna - Northern part of Nigeria. The laboratory experiments were conducted to determine the physical and mechanical properties of the selected timber species. The specimens were prepared in accordance with BS 373 for small clear specimens for the determination of physical and mechanical properties. Flexural strength properties were determined using three point bending test. Adjustment was made on the mechanical properties at moisture content of 12% and 18% in conformity with BS 5268-2 (2002) and NCP2 (1973) respectively. The laboratory data were analyzed using data analysis tool pack in Microsoft excel 2019 to generate the mean, coefficients of variation and theoretical distribution models which form the uncertainty models. Basic and grade stresses were also computed using experimental failure stresses. The selected timber species were then classified using the grade bending stress, density and mean modulus of elasticity obtained. Vitex doniana, Diospyros mespliformis, Parkia biglobosa and Isoberlinia doka were assigned to strength classes D30, D40, C40 and D30 in accordance with BS 5268-2 (2002) respectively. Similarly, in accordance with the NCP 2 (1973), these species belong to N4, N3, N4 and N3 respectively. The results obtained show that Vitex doniana, Diospyros mespliformis and Isoberlinia doka are hardwoods whereas, only Parkia biglobosa is a softwood species.

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“…Additionally, they had even less confidence in other species of wood used for construction in Uganda. While there exists limited information on the strength of these local wood species (Zziwa, Ziraba, & Mwakali, 2010), there were not enough references available to give the engineers great confidence in their assumptions. EMI's desire to increase confidence in material strengths they use for design prompted a collaboration opportunity with a U.S. academic institution for the limited testing of a variety of wood species.…”

Section: Materials Testing -A Collaborative Examplementioning

confidence: 99%

“…The overall goal of the study was to test Ugandan wood samples in general accordance with ASTM procedures to derive strength values in bending, compression, and direct shear. The collaborators selected four wood species based on their use in Ugandan construction, and because they had been included in a study published in the International Wood Products Journal (Zziwa, Ziraba, & Mwakali, 2010). Testing gave structural engineers using these materials another data point with which to compare the reasonableness of their design assumptions.…”

Section: Materials Testing Independent Studymentioning

confidence: 99%

Material Testing as an Opportunity for International Collaboration and Undergraduate Research

Pocock

Barrett

2017 ASEE Annual Conference &Amp; Exposition Proceedings

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This paper considers material testing of African wood species, performed by an engineering school in the U.S. on behalf of an international non-government organization (NGO), as research conducted partially by undergraduate students. The material testing program yielded useful information in itself, but the innovative method of international collaboration provides an example for educational institutions and NGOs of sharing resources for common benefits. Engineering Ministries International Uganda (EMI) provides design and construction management services to Christian charities throughout East Africa. Their structural engineers have been using North American timber standards to estimate the strength of similar African wood species, since little published information on the strength of locally-sourced African woods is available. Through the connection of the lead author's involvement with EMI during a recent sabbatical, EMI sent samples of cypress, eucalyptus, musizi and pine to the U.S. Air Force Academy's (USAFA) Department of Civil & Environmental Engineering for testing. Although the number of wood samples tested was small, the results provided EMI more confidence about the actual strength of these wood species used in East African construction, and are presented in this paper. The project also provided opportunities for undergraduate engineering students at USAFA and an EMI intern from Auburn University to participate in meaningful research. More collaboration is possible as Uganda Martyr's University (UMU) Faculty of the Built Environment considers involving its facilities and undergraduate students in continued testing. The testing results proved valuable to EMI, and the students involved gained experience setting up testing procedures and apparatus, conducting tests, recording data, and analyzing results. This unique approach of connecting North American and African universities, NGOs and undergraduate students required almost no funding and could be adopted by other similar organizations to simultaneously facilitate academic research and provide a valuable service not locally available. Many NGOs operating throughout the developing world would be grateful for such technical assistance. University engineering programs could provide this kind of testing and analysis as an opportunity for meaningful research. The level of complexity in such investigations can be appropriate for undergraduate participation with faculty guidance. Students are often drawn to engineering by a desire to benefit mankind. For example, faculty and undergraduate students at the Colorado School of Mines are helping EMI to evaluate the feasibility of small-scale solar-powered UV water disinfection systems. The authors assert that students are motivated to take part in research that helps people in developing countries improve the quality of their lives.

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Strength properties of selected Uganda timbers

Cited by 8 publications

References 12 publications

Wood properties and simulated modulus of elasticity of glulam in three fast-growing tree species grown in community forests in Yogyakarta, Java Island, Indonesia

Wood properties and simulated modulus of elasticity of glulam in three fast-growing tree species grown in community forests in Yogyakarta, Java Island, Indonesia

Characterisation and grading of four selected timber species grown in Nigeria in accordance with Bs 5268

Material Testing as an Opportunity for International Collaboration and Undergraduate Research

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