Experimental and analytical shear evaluation of concrete beams reinforced with glass ﬁber reinforced polymers bars Mohamed Said, Maher A. Adam, Ahmed A. Mahmoud, Ali S. Shanour ⇑ Department of Civil Engineering, Shoubra Faculty of Engineering, Benha University, 108 Shoubra St., Shoubra, Cairo, Egypt highlights  Glass ﬁber reinforced polymers (GFRP) bars were lab produced using local resources.  Shear capacity, deﬂection, GFRP stirrups/bars strains were recorded and discussed.  New approach to calculate FRP stirrups shear strength was proposed and veriﬁed.  Non-linear ﬁnite element analyses was performed and assessed with experimental results.  The shear capacities were calculated using the Strut and Tie Models (STM). article info Article history: Received 18 June 2015 Received in revised form 11 October 2015 Accepted 28 October 2015 Keywords: Concrete beams GFRP stirrups Shear Strut and tie models (STM) Non-linear ﬁnite element analysis (NLFEA) abstract This paper presents an experimental and analytical study on the shear behavior of concrete beams rein- forced with lab produced glass ﬁber reinforced polymers (GFRP) bars and stirrups. The bars and stirrups are manufactured by double parts die mold using local resources raw materials at lab. A total of ten beams measuring 120 mm wide, 300 mm deep and 1550 mm long were casted and tested up to failure under four-point load. The main parameters were concrete compressive strength and the vertical GFRP web reinforcement ratio in the form of the number of GFRP stirrups (without stirrups and with 8 @ 215, 8 @ 150 and 8 @ 100 stirrups). The mid-span deﬂection, inclined crack load and GFRP reinforcement bars and stirrups strains of the tested beams were recorded and compared. The test results revealed that the shear capacity increasing by 41% and 82% of the shear carrying capacity of beam without stirrups by using web GFRP reinforcement of 8 @ 215 and 8 @ 100 respectively. The shear capacity increased by 49% and 104% as the concrete compressive strength increased from 25 MPa to 45 MPa and 70 MPa respec- tively. The maximum value of measured strain in GFRP stirrups reached 0.0095. New approach to calcu- late FRP stirrups shear strength was proposed and veriﬁed throughout an assessment of experimental results of current study and previous works. The shear capacities of the tested specimens were calculated using the strut and tie models (STM) and non-linear ﬁnite element analysis (NLFEA). The average ratio of experimental shear capacity to calculated (V exp /V pred ) using NLFEA and STM were 1.2 and 0.9 respectively. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction An innovative solution to the corrosion problem is the use of ﬁber-reinforced polymer (FRP) as an alternative reinforcing mate- rial in concrete structures. In addition to the non corrodible nature of FRP materials, they also have a high strength-to-weight ratio that makes them attractive as reinforcement for concrete struc- tures. The location of the stirrups at the outer face of concrete ele- ments makes more vulnerable to harsh environmental effects, which accelerate the deterioration process and reduce the service life of the structure. Consequently, the use of FRP materials as an alternative shear reinforcement in reinforced concrete structures is becoming a more conventional countermeasure in structural members subjected to harsh environmental exposure. FRP prod- ucts are composite materials consisting of a matrix (resin) and reinforcing ﬁbers which are stronger than the matrix. To provide the reinforcing function, the ﬁber-volume fraction should be more than 55 percent for FRP bars and rods as recommended by many guidelines (ISIS Manual No.3 2007). The anisotropic behavior of FRP composites can be characterized by high tensile strength with no yielding only in the direction of the reinforcing ﬁbers. This http://dx.doi.org/10.1016/j.conbuildmat.2015.10.185 0950-0618/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail addresses: mohamed.abdelghaffar@feng.bu.edu.eg (M. Said), maher. adam@feng.bu.edu.eg (M.A. Adam), ahmed.m5882@gmail.com (A.A. Mahmoud), ali.shnor@feng.bu.edu.eg (A.S. Shanour). Construction and Building Materials 102 (2016) 574–591 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat