Shear behavior of concrete beams reinforced exclusively with longitudinal glass fiber reinforced polymer bars: Analytical model

A design approach based on the simplified modified compression field theory, but with the advantage of not requiring an iterative procedure, is proposed for evaluating the shear capacity of beams without including shear reinforcement. This model is capable of simulating beams flexurally reinforced with steel and fiber reinforced polymer (FRP) systems. To appraise the predictive performance of the proposed model, a database (DB) composed of 215 reinforced concrete beams without shear reinforcement is set. By applying the model to this DB, an average value for V-exp./V-ana. of 1.05 with a COV of 24% is obtained, where V-exp. and V-ana. are the shear capacity registered experimentally and obtained with the model, respectively. By applying the approach proposed by ACI Building Code to the DB, average and COV values of 0.91 and 42% are determined, revealing the higher predictive performance of the proposed model. This was even higher in the beams flexurally reinforced with FRP systems, since the proposed model conducted to average and the COV values of 1.0 and 22%, while 0.76 and 32% were obtained with the ACI approach. When proposed model was applied to the beams tested in the experimental program carried out, an average and COV values of 1.02 and 5.23% were determined.The second author wishes to acknowledge the grant SFRH/BSAB/114302/2016 provided by FCT. The support of the FCT through the project PTDC/ECM-EST/1882/2014 is acknowledged.info:eu-repo/semantics/publishedVersio

Shear behavior of concrete beams reinforced exclusively with longitudinal glass fiber reinforced polymer bars: Experimental research

This paper aims to investigate the shear failure mechanisms in beams exclusively reinforced with longitudinal glass fiber reinforced polymer bars and to propose a design-based approach to predict the shear capacity of this type of beams. An experimental program composed of seven T cross section shaped concrete beams was executed to analyze the influence of the flexural reinforcement configuration on the shear capacity and deformability of the beams. Three values of the flexural reinforcement ratio ((l)), 1%, 1.4%, and 1.80% were adopted. Digital image correlation technique was used to better capture and analyze the cracking process up to the formation of the shear failure crack. Test results indicated that the shear capacity was not dependent of (l) up to a limit of around 1.4%, but a tendency of the shear capacity to increase with (l) was registered above this limit due to a more pronounced favorable contribution of aggregate interlock and dowel effect.The authors gratefully acknowledge the ComRebars Company who supplied the GFRP reinforcement for the experimental tests. The third author wish to acknowledge the grant SFRH/BSAB/114302/2016 provided by FCT. The support of the FCT through the project PTDC/ECM-EST/1882/2014 is also acknowledged.info:eu-repo/semantics/publishedVersio