Erweitertes Druckbogenmodell für die Bestimmung der Querkrafttragfähigkeit von Stahl- und Spannbetonbalken

Extended compressive arch model to determine the shear capacity of rc/pc beams

Experimental investigations reveal that - especially in case of prestressed beams - the common truss model leads to a substantial underestimation of the true shear capacity. This is due to the negligence of the concrete shear capacity that can be determined using the compressive arch model as long as plane sections remain plane and only vertical cracks due to bending and no inclined cracks due to shear occur in state II. In case of inclined cracks due to shear plane sections do not remain plane. Hence, an extended compressive arch model is presented which also takes into account that parts of the acting shear force are covered by the truss model as a result of inclined cracks due to shear. This model can determine the concrete shear capacity resulting from arching effects even in case of existing shear cracks in state II. The presented model can be used for both prestressed concrete beams as well as reinforced concrete beams.