Strengthening of structural timber obtained from domestic fir and larch with CFRP

Timber, one of the oldest known building materials, has managed to reach the present day by competing with new building materials and constructive systems that emerged with the advancement of construction technologies, thanks to its various advantages. Timber is an anisotropic and hygroscopic material with mechanical properties that vary with direction. Over time, it suffers from strength loss due to natural defects present in its structure, cracks formed by swelling and shrinking when exposed to water, and insect and fungal infestation caused by moisture. Promoting the use of timber as a renewable and economical building material is possible through various strengthening methods. In this study, the effectiveness of carbon fiber-reinforced polymers (CFRPs) in strengthening structural timbers obtained from domestic species, fir, and black pine, is investigated. In this context, fir and black pine samples were subjected to four-point bending and axial compression tests in order to evaluate their axial compressive strength, bending strength and shear strength performances. Experimental results showed that reinforcement with CFRP generally improved the mechanical properties of both fir and black pine.