Study On Cracking Mechanism And Techniques For Prevention From Cracking In Inverted-T-shape Concrete Structures

The crack problem of inverted-T-shape concrete structures was rather thoroughly studied in the present paper. This paper analyzed the reasons of cracking and brought up the relevant engineering measures for the prevention from the cracking. The main contents of the present work are as follows:1. A 3-D simulative calculation FEM program concerning temperature field and creep stress field during the periods of construction and operation of concrete structures had been developed. By applying this program, temperature field and stress field of inverted-T-shape concrete structures could be simulated.2. Combining previous engineering examples, the reasons for cracking of inverted-T-shape concrete structures were thoroughly analyzed and researched. Sensitive analysis on stress state of pier caused by length of pier and elasticity model of ground and stress state of base mat caused by elasticity model of ground and thickness of base mat was made respectively. Their relations were quantitated.3. It dissertated the principle of improved accelerating genetic algorithm. The temperature parameters of concrete were back analyzed by this method in the scientific research of Jiangtanghu sluice.4. In accordance with the reasons expounded upward, many relevant engineering measures for preventing the cracking were brought up. By using the FEM program, the model was analyzed. The different conclusions could be drawn from using the engineering measures or not using them. This can help determine which of the engineering measures can be used at different time in the construction period.5. The research work was put into practice. Temperature control and crack prevention of pumping concrete of Jiangtanghu Sluice in Huoqiu county, Anhui province was studied as a case of the paper. The effect of cold wave strike, different superstratums, post-pouring belt and pipe cooling on the temperature and stress fields were studied in detail. The application was totally successful and there was no cracking in the project.