Research On The Performance Of The RC Beams Strengthened With High Performance Ferrocement

High performance ferrocement (HPF) technology is a new method to reinforce the concrete structure and masonry structure. Through testing and theortical analysis method, the basic load-bearing properties of the reinforced concrete (RC) beams strengthened with HPF are investigated. The reinforcement effect under different design conditions is analyzed, and the practical design formulas for the RC beams strengthened with HPF are proposed. The main achievements of this dissertation are described as follows.(1) Based on the test of 17 RC beams strengthened with HPF (BS) and 6 control member unstrengthened RC beams for comparison (BU), the flexural behavior of BS subjected to secondary load is investigated. The testing results show that the HPF technology can effectively increase the flexural capacity of RC beams. The incremental amplitude of the ultimate load-bearing capacity increases with the decrease of the initial longitudinal reinforcement ratio, the increase of the reinforcing rebar ratio and the strength of concrete and composite mortar, and descends as a result of the incremental once load. In general, HPF can cooperatively work with the initial concrete of BS, but debonding failure, even if bonded perfectly, always appears when the diameter of reinforcing rebar, or reinforcing rebar ratio, is great.(2) Based on the test of 12 BS and 4 BU, the shear behavior of BS subjected respectively to once and secondary load is investigated. The test results show that the HPF technology can effectively increase the shear strength of RC beams and improve the ductility capacity of RC beams. The incremental amplitude of the ultimate shear load-bearing capacity increases with the increase of the shear span ratio. The influence of the reinforcing rebar ratio on the shear strength is correlative to the shear span ratio. The larger the shear span ratio is, the larger the effect of the reinforcing rebar ratio is. The failure modes of BS in shear are shear-compression failure, diagonal- compression failure and debonding failure. As a whole, cracking formation of BS exhibits the shape of"thin and dense".(3) Based on the test of 10 BS and 4 BU, the crack-resisting capacity and the bending stiffness of BS subjected respectively to once and secondary load are investigated. The test results show that the HPF technology can effectively improve the bending stiffness of BS and suppress the appearance and expansion of the crack. The bending stiffness of BS subjected secondary load reduces more or less owing to the different once loads. Based on the testing results and referring to the calculation formula of code for design of concrete structures, the calculation formula of short-term...