Jin Wei-liang

EFFECT OF CORROSION ON BOND BEHAVIOR AND BENDING STRENGTH OF REINFORCED CONCRETE BEAMS

There is growing concern for corrosion damage in reinforced concrete structures with several decades’ service. Pullout tests and beam tests were carried out to study the effect of reinforcement corrosion on the bond behavior and bending strength of reinforced concrete beams. The bond strength of plain bars and concrete initially increases with increasing corrosion, then declines. The turning point depends on the cracking of the concrete cover. The bond strength of deformed bars and concrete increases with corrosion up to a certain amount, but with progressive increase in corrosion, the bond strength decreases, and the cracking of the concrete cover seems to have no effect on the bond strength. On the basis of test data, the bond strength coefficient recommended here, which, together with the bond strength of uncorroded steel bars and concrete, can be used to easily calculate the bond strength of corroded steel bars and concrete. The bond strength coefficient proposed in this paper can be used to study the bond stress-slip relationship of corroded steel bars and concrete. The bending strength of corroded reinforced concrete beams declines with increasing reinforcement corrosion. Decreased bending strength of corroded RC beam is due to reduction in steel bar cross section, reduction of yield strength of steel bar, and reduction of bond capacity between steel bar and concrete.

Reliability assessment of building structures under typhoon calamity

Typhoon is one of the most destructive natural calamities. Statistical data on 1949–1990 typhoons in China were used to analyze the frequency and strength of the typhoons, the relation between them and the average global ground temperature. The probability distribution of wind speed and the load of low buildings were obtained respectively on the basis of statistical data on the No. 9015 and No. 9711 typhoon. The finite element method and experimental comparison were used to obtained the probability distribution of lateral force resistance of a three-story brick-concrete building. Finally, the reliability indexes of this kind of building under No. 9015 and No. 9711 typhoon; and some valuable suggestions are given.

Four-function Principle for Optimization Design of Green High Performance Massive Concrete

A four-function principle was proposed for the optimization design of green high performance massive concrete (GHPMC) based on the theory of value engineering and the adiabatic temperature change control. A set of concrete formulas were designed according to the orthogonal experiment. The experimental results were analyzed by applying the variance analysis method to find out the effects of influential factors and determine the optimum mixture formula. In addition, the four-function principle was successfully applied to optimize the mixture formula in field massive concrete engineering. The practical results show the adiabatic temperature change of massive concrete could be efficiently controlled, and the excellent durability, good workability and high compressive strength could be achieved.