FEATURES OF THE CALCULATION OF REINFORCED CONCRETE ELEMENTS UNDER THE ACTION OF TRANSVERSE FORCE ACCORDING TO DIFFERENT STANDARDS

Abstract

Shear force action is probably themost studied type of damage to reinforced concretestructures with conventional or pre-stressedreinforcement. However, some issues remainunclear or controversial. In contrast to the resistanceto bending, there is not even a universally acceptedcalculation model that would describe the behaviorof structures under the action of a transverse force.In beams, the transverse force mostly actstogether with the bending moment. The stressedstate at any point of the beam is characterized bytotal stresses - a set of normal and tangentialstresses.At points where the tangential stresses are equalto zero, the main tensile and main compressivestresses act.The main platforms are inclined at an angle of45 and 135 to the longitudinal axis of the beam.On the neutral axis of the beam, where the normalstresses are equal to zero, the principal stresses areequal in value to the tangential (rocking) stresses.The principal compressive stresses can mostlybe absorbed by the concrete and are not, as a rule,decisive. The main tensile stresses are the mostdangerous. Since concrete does not resist tensionwell, the principal tensile stresses cause obliquecracks to form. The criterion for their occurrence isthe excess of the tensile strength of concrete by themain tensile stresses. If inclined cracks are formed,it is necessary to place appropriate reinforcement inthe wall of the beam, which perceives tension. Suchreinforcement can be either vertical or inclined bars.One of the main questions in various methods ofcalculating elements for the action of transverseforce is the question of what perceives it - onlyconcrete, only reinforcement, or both concrete andreinforcement?Despite some degree of uncertainty, the designof inclined sections can be carried out withconfidence, since the accepted methods ofcalculation in various norms have been checked andadjusted on the basis of a large amount ofexperimental data.