Wood is a building material with unprecedented environmental compatibility. However, span and cross-sectional dimension limitations, strength-reducing defects, and anisotropy limit their technical application. Mechanical joining methods to address previous challenges have resulted in severe wood fiber breakage and increased endogenous energy in wood as an environmentally friendly material. However, industry groups are working to overcome these limitations and use wood that can be glued beyond traditional uses in Nigeria, using those wood species to create processes such as glue-laminated timber (laminated timber). The literature identifies the potential for developing wood products. Conversely, wood has shown little or no interest as a building material in Nigeria, but most studies on wood have focused on the solid wood element and ignored its limitations. As a result, its structural capacity has not yet been evaluated. Nonetheless, the fact remains that restoring natural wood as laminated timber is an effective way to optimize this eco-friendly material for an unlimited number of structural uses. Whether these qualities can be achieved in natural wood is the main focus of this study. Therefore, the study involved laboratory experiments on selected types of wood. Ire (Funtumia africana), Awun (Alstonia congensis), and Oriro (Antiaristoxicaria) are readily available and widely distributed species, and his NCP 2 of 1973 has no information on Oriro and Ire. The aim was to evaluate the strength properties as glued laminated timber elements with the aim of improving their load-bearing capacity. We also determine the effect of temperature change on the cohesion, i.e. the compressive strength parallel to the grain of short columns of glue-laminated timber, by exposing three identically sized samples to different temperatures of 0°C and 40°C. is needed. Heat in an electric oven for 4 hours at 50°C, 70°C, 100°C and room temperature before testing. Compare the mechanical properties of solid and glue-glued wood elements. A sample was prepared and tested for promotion. Static flexural strength, parallel and perpendicular grain compression, density and moisture content according to ASTM D193, EN 408(2003) and EN13183-1(2002). Studies have found that the species are: The structural adhesion at which the BSH column loses compressive strength from the control temperature (30°C and 27.90°C) to 100°C was 41.4% and 21.6% for Ire, Awun and Oriro. The results showed that the laminated timber elements exhibited flexural strengths of 55%, 95%, and 143% of that of clear solid wood, and 65.22 N/mm2. 36.44 N/mm2, 26.15 N/mm2; 25 N/mm2 and 14 N/mm2; 20 N/mm2 are structurally significant in wood species solid and glued glued-glued. Thus, this study showed that the investigated types of wood can be processed into load-bearing bonded structural elements using polyvinyl acetate adhesives at both below and above room temperature without significant loss of strength.

chapter One
1.0 Introduction

1.1 Research background
Wood’s versatility makes it widely used in the construction industry, from simple framing of residential projects to large public facilities. However, wood is of limited value as a structural material for a wide range of structural applications due to limitations in span and cross-sectional dimensions due to the size of the tree and the characteristic loss of strength that occurs as it grows. Engineered wood products, such as bonded glued laminated timber (BSH), have therefore been developed to improve the use of natural wood beyond its natural limits.
Structural glued-laminate timber is engineered structural timber glued from appropriately selected and prepared strips of stress gradient timber, with the grain in all strips substantially parallel to the longitudinal axis of the member (APA , 1996; Manja et al., 2010). According to the American Plywood Association (APA, 2013), laminated wood remains the most resource efficient approach to wood construction products when it comes to optimizing products from carefully managed wood resources. Glued-glued timber can be constructed from defective wood without loss of strength properties, as reported by Regina et al., (2010). Therefore, the use of glue-glued timber as a construction material allows many types of wood previously considered non-commercial to be used for construction purposes. This clearly has the potential to restructure forestry and make it a large employer of the labor force. Glue-glued timber can also be made from small-diameter, fast-growing trees, filling the supply gap of slow-growing trees (Evalina et al., 2010). According to the American Timber Structural Institute.



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