Flexural behavior of ECC reinforced RC beams under secondary load: Experimental, numerical simulation and theoretical analysis

The aim of this paper is to study the flexural behavior of reinforced concrete (RC) beams reinforced by engineered cementitious composite (ECC). The reinforcement effect of ECC on RC beam is studied by experiments, numerical simulation and theoretical analysis, considering the secondary load. Five beams were tested under static load, including two beams with ECC layers at the top and bottom (TBEB), two beams with ECC layers at the bottom (BEB) and one unreinforced beam. Different parameters in the test include reinforcement ratio, whether the top is equipped with ECC layer, and the thickness of the top ECC layer. The test data were used to validate the finite element model developed to simulate the bending response of the ECC layer reinforced beam. Then, a series of parameter studies were carried out to evaluate the effects of ECC layer thickness, reinforcement ratio and ECC elastic modulus on the reinforced beam. The experimental and numerical simulation results show that compared with other reinforced beams, TBEB equipped with 50 mm ECC layer at the top and bottom has better performance. Compared with the control beams, the ultimate bearing capacity is increased by 82.6 %, ductility and deformation capacity are increased by 2.38 times and 2.11 times, respectively. Finally, a calculation model for predicting the flexural capacity of TBEB is presented. The predicted flexural capacity is in good agreement with the experimental results.