Papers by Author: Xiao Hong Zheng

Abstract: Steel fiber reinforced polymer high strength structural concrete (SPHSC) is a new composite material which is used in long-span bridge structures invented by this research team. Based on the new composite material, the experiments of stress-strain full curves under uniaxial compression were carried out. The stress-strain full curves were achieved from the simple improved method. By the method of theoretical derivation and experimental data fitting, the constitutive equation of SPHSC which contains only two undetermined parameters of compressive strength and parameter of steel fiber was obtained. The study is the theoretic basis of the new material which was widely use in civil engineering.

Abstract: Peeling along the interface between FRP and concrete under fatigue load is the common failure pattern for the RC structures strengthened with FRP. In this paper, five groups specimens were subjected to fatigue load to study the fatigue mechanism for bonding interface between carbon fiber laminate (CFL) and concrete. The Δσ~N curves for the bonding interface were derived from the experiments, the laws of strains and slip on interface were analyzed in this paper.

Abstract: To discover the fatigue behavior and durability of the new type fiber concrete named “steel fiber reinforced polymer high strength concrete (SFPHC)”, considering climatic conditions in Guangdong Province, using research method of theoretical analysis combined with experimental study, thermal fatigue behavior of SFPHC used in bridge superstructure in three different temperatures (20°C，50°C，80°C) is discussed and compared with concrete C60 which has similar static mechanical properties at room temperature. The results show that the thermal fatigue performance of SFPHC can be described effectively with the proposed computing formula, and the fatigue performance has been greatly enhanced compared with the C60 concrete.

Abstract: Defects like surface crack often appear in steel structures. To ensure the structural integrity and security, the new material such as fiber reinforced polymer (FRP) was adopted for strengthening and repairing. In this paper, three dimensional semi-elliptic surface crack in steel tension specimen strengthened with carbon fiber laminate (CFL) was studied, and numerical analysis was undertaken by Abaqus finite element software to study the stress intensity factor (SIF, KI) of the surface crack for CFL reinforcement effect. The results showed that, strengthening effect of CFL in front side was better than the back side of the steel plate; Crack shape ratio, a/c, had greater influence on strengthening effect in front side compared with little effect in the back side; The changes of crack relative depth, a/B, affected strengthening effect.

Abstract: External bonding of fiber reinforced polymer (FRP) plates or sheets composites has become a popular technique for strengthening concrete structures all over the world. The bond strength between FRP and concrete is a key factor controlling debonding failure of various forms in FRP-strengthened concrete structures. Based on the test data, the bond strength model of FRP-concrete was proposed using multiple linear regression and dimensional analysis, in which the effect of multiple factors on dependent was considered. Finally, the proposed model was verified through the test data, and then compared with 12 bond strength models have been found in the existing literature. The result shows that the proposed model has a better accuracy. It can be used to predict the bond strength of FRP-concrete.