Available online at www.CivileJournal.org Civil Engineering Journal Vol. 6, No. 11, November, 2020 2143 Flexural Behavior of Composite GFRP Pultruded I-Section Beams under Static and Impact Loading Abbas A. Allawi a , Safaa I. Ali a* a Department of Civil Engineering, College of Engineering, University of Baghdad, 10071, Baghdad, Iraq. Received 28 June 2020; Accepted 15 October 2020 Abstract In this study, the effect of glass fiber reinforced polymer (GFRP) section and compressive strength of concrete in composite beams under static and low velocity impact loads was examined. Modeling was performed and the obtained results were compared with the test results and their compatibility was evaluated. Experimental tests of four composite beams were carried out, where two of them are control specimen with 20 MPa compressive strength of concrete deck slab and 50 MPa for other. Bending characteristics were affected by the strength of concrete under impact loading case, as it increased maximum impact force and damping time at a ratio of 59% and reduced the damping ratio by 47% compared to the reference hybrid beam. Under static loading, there was an increase in all the parameters, including the maximum load, ductility, and stiffness. Mid-span deflection was reduced by 25% under static and impact loads. A finite element analysis was performed by using the ABAQUS software. The midspan deflection value was greater than the experimental values by 6% and 3% for impact and static loads, respectively, and all other results showed a high rate of agreement with the obtained test results. The agreement between the numerical and experimental results indicates that the developed numerical model is capable of analyzing the impact and static behavior of such hybrid GFRP-concrete system. Keywords: Glass Fiber Reinforced Plastics (GFRP); Concrete; Shear Connection; Hybrid Beams; Composite Beam; Pultruded FRP. 1. Introduction Fiberglass Reinforced Polymers (FRP), also known as fiber-reinforced plastics or Advanced Composite Materials (ACMs), are composite materials made of a matrix of polymer resins reinforced with compact fibers typically glass, carbon, basalt or aramid. The polymer is usually an epoxy, vinyl or thermoplastic polyester or phenol-formaldehyde resin. The strength of the FRP fragment is mainly determined by the type of fiber and its orientation, amount and location within the fragment. The type of resin used determines corrosion resistance, flame retardant, and maximum operating temperature; it also significantly contributes to some strength characteristics including shock resistance and fatigue. There are many FRP products used in civil / structural engineering applications. Among those that have become increasingly common in the last two decades are structural Glass Fiber Reinforced Polymeric (GFRP) sections. Composite materials in the form of pultruded glass fiber reinforced polymer (GFRP) profiles have a great potential since they are economically affordable through the pultrusion process, which offers the best productivity/cost ratio of all the composites fabrication processes. However, when combined in a hybrid form with concrete, they have shown to offer excellent performance as floors, bridge decks, and beams when subject to static and impact loadings. * Corresponding author: safaa.ib90@gmail.com http://dx.doi.org/10.28991/cej-2020-03091608 © 2020 by the authors. Licensee C.E.J, Tehran, Iran. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).