Reinforced concrete members should have an adequate safety margin against shear failure, whichrnhappens to be brittle and sudden. A lot of variables contribute to the shear resistance of beams, andrnto predict the resistance their influence to the shear behavior should be studied thoroughly. Past rnresearches indicated that side cover spalling was observed for beams subjected to shear, signifyingrnout of plane deformation had resulted from an in-plane loading. This observation however has notrnbeen explored enough to understand the mechanism and effect of side cover spalling in the overallrnstructural resistance of reinforced concrete beams. rnTo investigate the effect and mechanism of side cover spalling under different variables seven fullrnscale shear critical reinforced concrete beams were tested under one-point monotonic loading.rnVariables under consideration were concrete side cover thickness, stirrup cage width, and stirruprnspacing. The specimens were also analyzed in a two-dimensional nonlinear finite elementrnsoftware, VecTor 2. Furthermore, the study assessed current code provisions and shear designrntheories for the design of beams subjected to shear, and checked whether or not spalling affectsrnthe ultimate resistance of a beam. rnFrom the experimental program out of plane deformation strains were recorded for all testedrnspecimens regardless of their side cover thickness. This deformation led to side cover spalling nearrnpeak load exemplifying that, stirrups are planes of weaknesses where spalling happens. Variablernside cover thickness and stirrup spacing had observable effect on the spalling mechanism of thernbeams. The variation of side concrete cover thickness and spalling did not compromise the loadrnresistance of beams as long as the core concrete confined within the stirrups was adequate enoughrnto resist the applied loads. However, pre-peak spalling followed by premature failure happened forrnspecimens designed with a relatively reduced stirrup cage width. rnExisting international codes including Eurocode 2 (EN 1992-1-1:2004), ACI Standard (ACI 31814),rnCanadianrnStandardrn(CSArnA23.3-14),rnandrnJapanesernCodern(JSCErnStandard,rn1986),rnconsiderrnthernrnentirernbeamrnrnwidth (bw) to be effective for shear resistance and consequently uses it as such forrnultimate capacity prediction. Code prediction gave an overestimated failure load for specimensrnwith reduced stirrup cage width, which demonstrates the inadequacy of design code provisions forrnbeams subjected to shear with regards to the usage of the entire beam width ( bw) for capacityrnprediction.