Technical Report The effect of the wrapped carbon fiber reinforced polymer material on fir and pine woods Hale Gezer a , Bulent Aydemir b, * a Yeni Yuzyil University, Engineering and Architecture Faculty, Taksim, Istanbul, Turkey b TUBITAK, National Metrology Institute (UME), P.K. 54, 41470 Gebze Kocaeli, Turkey article info Article history: Received 21 October 2009 Accepted 16 February 2010 Available online 19 February 2010 abstract The aim of this study is to observe the strength changes of the wood material. The compression and bend- ing strength of the specially wrapped wood materials were investigated. Carbon fiber reinforced polymer (CFRP) material was wrapped onto the wood surface by using a polymer-based glue. The strength ratio of the wrapped and non-wrapped materials was investigated. The specimens were prepared from fir and pine woods that are used widely in buildings. At the same time, two types of woods were compared in terms of strength ratios. As a result of this study, the increase of the compression and three-point bending strength was determined for wrapped CFRP wood materials. Crown Copyright Ó 2010 Published by Elsevier Ltd. All rights reserved. 1. Introduction Among many materials, the common use of wood material in traditional materials draws the best attention in every period. For wood and wooden skeleton buildings, base chord, derrick, cap chord, and traverse (abutment) are used as the main building components with auxiliary components, whereas space chords, auxiliary derricks, and paving chords are used as auxiliary building components [1]. Despite the widespread use of wood in traditional architecture, new studies of structure systems and the wider openings of the new structures inhibited the usage of wood for a certain period. Since wood comes from trees (which are living organisms), the size and complex structure of the material have been considered to cause problems. Wood is a mixed material composed of complexly lined cellulose cells, including a polymer called lignin, and the material is strengthened with other organic compounds. The static properties of the material are not identical at every point and in every direction (anisotropic material) due to the non-homogeneity and complexity of the natural wood. This characteristic of the wood can be considered to be one of its negative properties [2]. To- day, these negative properties of wood have been resolved with the development of various protective coating methods and the pro- duction of new composites. Synthetic wood material, manufac- tured from natural wood, has some superior and positive properties compared to the other building materials and, for this reason, synthetic wood is preferred in modern building structures. One hundred to two hundred meter gaps are connected with adhesive-layered laminated chords. Having light structural compo- nents (density: 1400 kg/m 3 ) leads to a considerable decrease in the size of the vertical supporters and fabrication dimensions. The lam- inated wood components are approximately 1/6 times lighter than reinforced concrete components. Light-weight laminated wood structures also mitigate the possible effects of an earthquake on a building; this type of construction would be earthquake-proof [3]. These properties are further developed in composite structures. The resistance of fiber-equipped composites to especially tension, bending, and impact-related damage is increased. In addition, improvements of some other properties are also observed [4]. In early investigations, textile-incorporated plastic pipes were coated with a concrete layer in the ‘Technische Universitat Dres- den’ University. Using various methods, hollow cylindrical wooden tubes and elbows are coated with 3D-knitted fabric cloth under the same conditions and, as a result of the strengthening process, the displacement is doubled under a load [5]. The steel reinforced beams were glulam wood beams that were fully covered on one side using a steel plate with a thickness of 1.5 mm. The CFRP rein- forced beams were glulam wood beams covered with CFRP. The re- sults indicate that the behavior of the reinforced beams is totally different from the un-reinforced ones. The reinforcement has chan- ged the mode of failure from brittle to ductile and has increased the load-carrying capacity of the beams [6]. The subject of another study is to state reinforcement of existing wood elements under bending loads with the use of fiber-reinforced polymer (FRP) mate- rials. In this study, mechanical tests on the reinforced wood showed that external bonding of FRP materials may increase the 0261-3069/$ - see front matter Crown Copyright Ó 2010 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.matdes.2010.02.031 * Corresponding author. Address: TUBITAK-UME, P.O. Box 54 41470 Gebze- Kocaeli, Turkey. Tel.: +90 262 679 50 00; fax: +90 262 679 50 01. E-mail address: bulent.aydemir@ume.tubitak.gov.tr (B. Aydemir). Materials and Design 31 (2010) 3564–3567 Contents lists available at ScienceDirect Materials and Design journal homepage: www.elsevier.com/locate/matdes