Study On Steel Reinforced PP ECC Beams Under Reverse Cyclic Loading

The necessity for the use of chemical fiber in concrete engineering was shown and therelated fundamental research on PP ECC, advantages of adding ECC and development trend ofECC in all engineering fields were summarized. PP ECC properties and strengthening theory offiber concrete were described，as references for further exploiting fiber concrete engineeringfunction and the explanation of improvement mechanism at the beginning of the thesis.The mechanical property of steel reinforced PP ECC beams under reverse cyclic load isinvestigated and results are presented in this paper. Five types of PP ECC beams and one controlR.C beam of cross section150×200mm and a span length of1.2m were constructed The reversecyclic bending tests were controlled by imposed deflection. The influence of reinforcement ratio,curing age and volume fraction of PP fiber on load bearing capacity, energy dissipation andstiffness degradation is investigated. The maximum crack width of PP ECC beam is below0.3mm and not crushing of ECC is observed during the whole loading process. The resultshighlighted the positive contribution of PP ECC to enhance strength and energy dissipationcapacity which is important to evaluate the performance of structures subjected to reverse cyclicloads.On considering of the concrete damage Plasticity，this paper verificated the skeleton curvethrough the application of the ABAQUS finite element analysis software. And apply a reasonablesimulation method to analyse a number of impact factors of the variable-beam joints of R. C.frame structure and get the nonlinear behavior influence rule of change the size of both sides ofbeams.According to the experimental study on mechanical behavior of steel reinforced PP ECCbeams under reverse cyclic loading，the formula of model parameters related to reinforcementratio are proposed and deteriorating double lines restoring force model of steel reinforced PPECC beams under reverse cyclic loading is established. Compared with experimental results inthe experimental study，it is founded that the restoring force model established is of a certaindegree of adaptability.