Use of FRP pultruded members for electricity transmission towers Ahmed Godat a,⇑ , Frédéric Légeron b , Vincent Gagné b , Benjamin Marmion b a Department of Construction Engineering, École de Technologie Supérieure, Université de Québec, Montreal, Québec H3C 1K3, Canada b Department of Civil Engineering, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada article info Article history: Available online 31 May 2013 Keywords: FRP pultruded members Electricity transmission towers Experimental results Prediction models Design equations Cost estimate abstract This study investigates the replacement of traditional materials (steel, wood and concrete) in electricity transmission lines by fiber glass pultruded members. The first part of the study summarizes a comparison between different design approaches to experimental data for glass fiber pultruded sections. For this pur- pose, a total of fifteen specimens made of E-glass and either polyester or vinylester matrix are tested: (i) angle-section, square-section and rectangular-section specimens are subjected to axial compression; (ii) I-section and W-section specimens are tested under bending. The experimental results are summarized in terms of the failure mode, critical buckling load and load–displacement relationships. Design equations available in FRP design manuals and analytical methods proposed in the literature are used to predict the critical buckling load and compared to the experimental results. Design of various FRP pultruded sections and cost estimate are conducted for 69 kV electricity transmission portal frame and a total distance of 10 km. The significance of the present findings with regard to economic solutions is discussed. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Fiber reinforced polymers (FRP) represent a new class of con- struction materials. Advances in pultrusion technology lead to pro- duce larger pultruded parts capable of serving as structural members [1,2]. The characteristics of low conductivity, light weight and ease of assembly present the opportunity of FRP to re- place the steel in electricity transmission towers. In addition, FRP is very durable as it is characterized by its extensive use in the mar- ine industry over a long period. This makes the FRP an interesting material to be evaluated structurally. However, most fabricators of FRP transmission lines produce FRP pole products similar to wood transmission lines by providing the capacity based on the pole height. Even if this approach has proven its effectiveness for some projects, there is no study in the literature, up to the authors’ knowledge, to evaluate the possibility of direct designing FRP pul- truded members for electricity transmission lines. This approach would improve the optimization of structures at the line system le- vel according to line configurations and loadings. Using such opti- mization, engineers can design electricity transmission lines with the most appropriate material (wood, steel, concrete or FRP). In addition, structures can be designed with different configurations such as wood portal frames, steel tower or hybrid structure using different materials. At this moment there is no standard for the design of FRP pul- truded members. However, in the past two decades, numerous studies described the structural behavior of FRP pultruded mem- bers. A considerable amount of experimental tests were carried out to investigate the behavior of I-section FRP pultruded members pertaining axial compression [3,4,5,6,7,8,9,10,11,12]. Relatively, few researches exist on the buckling behavior of angle-section members [13,14], T-section members [15] channel-section mem- bers [16,17,18,15,19] as well as box-section members [20,21,14]. Some studies were performed to investigate the local buckling and lateral-torsional buckling of beams under transverse load [22,23,24,25,26,27,28,29,17,30,31,32,33,34,35,36]. A study exam- ined the shear deformability of a beam with a U-section under transverse load is found [37]. Valuable studies investigated a frame made of FRP pultruded members and subjected to vibration are carried out by Boscato and Russo [38] and Russo [39]. Buckling is the dominant failure mode that occurs in FRP pul- truded members due to its relatively low stiffness associated with small thickness. Whether it is in compression or bending, buckling generally appears at low stress and prevents FRP pultruded mem- bers from attaining their full capacity. Even though substantial re- search studies on the behavior of FRP pultruded members have been conducted, reliable design criteria is still absent. In addition, there is no detailed study to evaluate design manuals proposed by different FRP manufacturers to predict the critical buckling capac- ity against reliable experimental data. Therefore, it remains diffi- cult for structural engineers to decide the appropriate design procedure when designing structures made of FRP pultruded members. 0263-8223/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.compstruct.2013.05.025 ⇑ Corresponding author. E-mail addresses: Ahmed.Godat@etsmtl.ca (A. Godat), Frederic.Legeron@Usher- brooke.ca (F. Légeron), Vincent.Gagne@USherbrooke.ca (V. Gagné), Benjamin.Mar- mion@gmail.com (B. Marmion). Composite Structures 105 (2013) 408–421 Contents lists available at SciVerse ScienceDirect Composite Structures journal homepage: www.elsevier.com/locate/compstruct