Crack-Based Assessment of a 4-meter Deep Beam Test

The maintenance or replacement of bridges, transportation networks, and critical civil buildings is a major problem in many western countries as a large stock of structures built during the high economic growth period are rapidly approaching the end of their service life. At the same time, because the rehabilitation resources are limited, it has become increasingly more important to enhance the structural assessment methodologies used to identify, prioritize and aid cost-effective interventions. While existing approaches can be used to predict crack information for comparisons with observed response, there remains a need to establish methods that use crack measurements as a direct input to assess the structural safety level. Of particular interest are heavily-loaded lightly reinforced deep members that can exhibit wide cracks and brittle failures. The structural response of such members is highly dependent on the specific critical crack shape that the member exhibit. This research further develops crack-based assessment approaches for deep beams that utilize the Two-Parameter Kinematic Theory (2PKT) as a framework for structural assessments. Information regarding the modelling of local response of transverse reinforcement along cracks, as well as the importance of accounting for member-specific crack geometry are discussed. The crack-based assessment approach is used to provide a detailed insight into the shear behaviour of a unique 4-meter deep beam test in the literature. The predicted response of this specimen is discussed and compared against experimental measurements such as global and local deformations as well as shear strength. Finally, the research presented in this paper demonstrates that accounting for detailed crack information significantly improves assessment results. The proposed modelling framework therefore contributes towards the establishment of mechanics-based crack-assessment approaches for lightly reinforced concrete deep members.