Structural evaluation and design procedure for wood beams repaired and retrofitted with FRP laminates and honeycomb sandwich panels

Abstract

a b s t r a c tAs compared to other structural applications of polymeric composites, limited information is available on structural behavior of wood members strengthened with polymer composites. The focus of this paper is to evaluate the structural performance and practical use of wooden beams repaired and retrofitted with fiber-reinforced-polymeric (FRP) composites. The paper presents a summary results of an experimental study on the behavior of both Douglas Fir and Glulam wood beams repaired and retrofitted with different composite strengthening systems. In addition, the paper presents a simplified design procedure to predict the capacity of timber beams strengthened with FRP composites. Two types of composites; wet layup laminates and sandwich panels, and two lamination schedules; unidirectional and bidirectional, and two lamination geometries; U-laminate and flat laminates were evaluated. For "flexure/shear" wood beams repaired and retrofitted with bidirectional, carbon/epoxy U-shaped wet layup laminates, a total of eight Douglas Fir (Dug Fir) Larch # 1 wood beams were tested to failure. For "flexure-only" wood beams retrofitted with flat unidirectional laminates, both wet layup and precured sandwich honeycomb composites were evaluated. Experimental results indicated that the use of composites as external repair and rehabilitation elements resulted in an appreciable increase of both strength and stiffness. A practical case study is also presented that provides a step-by-step procedure for analyzing and designing a polymeric composite system for repair of partially damaged wood girders by fire.

Effect of Selected Factors on the Bending Deflection at the Limit of Proportionality and at the Modulus of Rupture in Laminated Veneer Lumber

“…In addition to synthetic fiber reinforcement, natural fiber reinforcement may also be used, e.g., in the form of a nonwoven fabric. Experimental research has shown that correctly locating the reinforcement component has the potential to increase the bending characteristics of laminated wood in the case of application on the stressed tensile zone [21,29,30].…”

Impact of hygrothermal aging on rotational behavior of web-flange junctions of structural pultruded composite members for bridge applications

“…Figures (6) and ( 7) present details of the J-group and AJ-group specimens evaluated in this study, respectively. It should be noted that in this paper, the pultrusion direction is denoted as 0 0 directions, while direction contains θ degree clockwise with pultrusion direction is denoted as θ 0 direction and direction contains θ degree counter-clockwise with the pultrusion direction is denoted as -θ 0 direction.…”

“…In terms of high strength, light-weight, corrosion resistance and continuous manufacturing features, pultruded fiber reinforced polymer (PFRP) composites have been used in several successful applications both in newly constructed facilities applications [1][2][3] as well as repairing deteriorated structures [4][5][6]. For new structures, commercially produced, steel-like, unidirectional pultruded profiles are commonly used including H-girders [7][8][9], double-web beam girders [10][11], hybrid FRP-concrete girders [12], box girders [13], stay-in-place (SIP)…”

Bending Stiffness of Hybrid Wood-Metal Composite Beams: An Experimentally Validated Numerical Model

“…Therefore, new technologies are being introduced to enhance wood based on hybrid composite designs [3][4][5][6][7]. Modern beams can thus be strengthened in the production phase [8], or old wooden beams can be repaired and retrofitted by adding FRP laminates [9][10][11][12][13][14][15][16][17] and honeycomb sandwich panels [18]. This strengthening can even be made reversible [19] or, in certain cases, adaptive [20].…”