Schrägrissbildung von Stahl beton balken unter Querkraftbeanspruchung

摘要

Material aging and increasing traffic loads make structural assessment of existing bridges necessary. A common result of structural assessment of reinforced and prestressed concrete bridges using new refined design approaches is often a lack of shear resistance. For the ongoing evaluation of shear resistance, especially of structural members with low shear reinforcement ratios or without shear reinforcement, an investigation of further load bearing mechanisms is essential. One of these mechanisms is the contribution of concrete tensile strength, which is the dominant load bearing mechanism until diagonal cracks appear.In a current research study at the iBMB, Division of Concrete Construction of the TU Braunschweig as a part of the Graduate College 2075, funded by the German Research Foundation (DFG), the ACI-DAfStb Database of shear tests on concrete members without shear reinforcement was extended with diagonal cracking loads and evaluated regarding the influence of parameters such as shear span ratio, longitudinal reinforcement and concrete strength. Suggested mechanical approaches in the literature for the evaluation of diagonal cracking load were assessed using the extended database. Based on the results, an appropriate model for the evaluation of diagonal cracking load of reinforced concrete members is verified and consequently simplified to an engineering model.