DEVELOPED PROBABILISTIC REDUCTION FACTORS FOR LOPHIRA ALATA (EKKI) TIMBER JOISTS SUBJECTED TO CREEP-RUPTURE

Authors

  • JM Kaura DEPARTMENT OF CIVIL ENGINEERING, AHMADU BELLO UNIVERSITY, ZARIA, KADUNA STATE, NIGERIA
  • A Lawan DEPARTMENT OF CIVIL ENGINEERING, AHMADU BELLO UNIVERSITY, ZARIA, KADUNA STATE, NIGERIA
  • AA Salihu DEPARTMENT OF CIVIL ENGINEERING TECHNOLOGY, NUHU BAMALLI POLYTECHNIC, ZARIA, KADUNA STATE. NIGERIA

DOI:

https://doi.org/10.4314/njt.361.1211

Keywords:

Creep-rupture, Lophiraalata, reliability, uncertainties, Gerhards

Abstract

Wood experiences a significant loss of strength and stiffness when loaded over period of time. This phenomenon is known as creep-rupture. Several models were developed for the estimation of the reduction of load carrying capacity of timber with time. In this paper, the results of time dependent structural reliability analysis of timber joist produced with Lophiraalata (Ekki) timber specie was presented. Three load duration models were considered in the study, namely: The Model proposed by Wood, Gerhards model, and Nielsen. The timber joist was designed in accordance with the Eurocode 5. The uncertainties in all the basic design variables were fully accommodated in the time dependent reliability analysis. The entire process was implemented using a developed MATLAB program employing First Order Reliability Method (FORM). Time dependent mathematical models for modification of safety index to account for the effect of load duration were proposed. The use of both Gerhards and Nielsen model, for the design of Lophiraalata timber members was recommended.

 

http://dx.doi.org/10.4314/njt.v36i1.6

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Section

Building, Civil & Geotechnical Engineering

How to Cite

DEVELOPED PROBABILISTIC REDUCTION FACTORS FOR LOPHIRA ALATA (EKKI) TIMBER JOISTS SUBJECTED TO CREEP-RUPTURE. (2016). Nigerian Journal of Technology, 36(1), 39-44. https://doi.org/10.4314/njt.361.1211

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