Usage of Casuarina junghuhniana Mig. as Structural Components

Abstract

Casuarina junghuhniana Mig. is fast-growing wood originated in Indonesia and cultivated in Thailandsince the late 19^thcentury. Now it can be found everywhere in Thailand. At present, this wood is used mainly forfurniture, pile, charcoal, and parquet, etc. It is not popularly used as structural components because of the lackof its engineering data for decision making. Therefore, the objective of this research is to study physical andmechanical properties of Casuarina junghuhniana Mig. Then the statistical properties under the confidenceinterval of 99% and failure probability calculation would be carried out. The research scope covers three buildingtypes i.e. residence, offices, and schools. The building height is limited to two storeys and floor-to-floor height is 3.00 meters. The building design is in accordance with E.I.T. Standard (The Engineering Institute of Thailandunder His Majesty the Kings Patronage). Finally, the appropriate size of each structural component would berecommended.

Results showed that most properties could be represented by normal distribution. Analyses of structuralmembers spanned 3.00 meters were based on the accepted values of failure probability less than 10^-4 for thedeflections of joist and beam, less than 10^-6 for short term buckling loading, and 10^-2 for long term bucklingloading. The size for each component was recommended as followed :

11/2"x8" joist could be used in residence, office, and school which received live load of 150 kg/m², 250kg/m², and 300 kg/m², respectively. The appropriate spacing of joist is 50, 35, and 50 cm for each building type,respectively.

2-2"x 10" beam was recommended for residence and school. Whereas 2-2"x12" beam was recommendedfor office.

For columns, the safety factor value of 3.3 in Euler’s equation was recommended for all cases.