Analytical Modeling of Load-Deflection Curve in Reinforced Concrete Beams

Document Type : Research Article


1 Assistant Professor, Faculty of Engineering, Islamic Azad University, Roudehen branch, Tehran

2 Professor, Faculty of Civil Engineering, Amirkabir University of Technology, Tehran

3 M.Sc., Construction Management, UTM University of Malaysia, Skudai, Johor, Malaysia


During some deflection tests of concrete beams, the measurement instruments are damaged in the concrete failure moment. Because of this damage, load-deflection data becomes insufficient and therefore application of a better method is in need. In the load-deflection relation, the reinforced concrete beam has an elastoplastic behavior and load-deflection curve can be obtained by an analytical model. The aim of this paper is to propose an analytical model to figure out the load-deflection curve in the situation that the measurement instruments are damaged. For this purpose, an experimental model is initially built and concrete strength parameters are calculated through the 4-point test. Then an elastoplastic analytical model is proposed and the same parameters are calculated again. Comparison of the results of two models shows that the error rate of the analytical model is less than 9 percent. Hence, the proposed model has a good agreement with the experimental model and is useful when the measurement instruments are damaged during the test.


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