Analytical approach for predicting the moment-curvature response of structural lightweight reinforced concrete beams

With the switch towards performance-based design procedures, the prediction of the flexural behavior of lightweight reinforced concrete, LWRC, members using advanced and reliable analytical tools has been of great interest to researchers. This paper proposes nonlinear analytical and numerical procedures based on sectional analysis and finite element methods for predicting the moment-curvature and load-deflection responses of structural LWRC beams subjected to pure bending. The proposed analytical and numerical models were validated experimentally by casting and testing a series of eight full-scale LWRC beams under four-points bending configuration. The effects of different compressive strengths of concrete and tensile reinforcement ratios on the flexural behavior of LWRC were examined. The analytical and numerical predictions of the load-deflection behavior and the moment-curvature and load-deflection responses of the LWRC beams investigated, compared very well with the corresponding responses measured from experiments, and test results of previous studies existing in the literature. Among the parameters evaluated using sensitivity analysis, the compressive strength had a significant influence on the flexural strength and stiffness of LWRC beams, whereas the compressive reinforcement ratio was the most important factors affecting the energy absorption and curvature ductility. Moreover, the theoretical models developed could serve as viable tools for simplifying the design process of structural lightweight reinforced concrete members and enhance their applications.