Study On Cracking Control Of Steel-Lined Fiber Reinforced Concrete Penstocks

In this paper the problem of outer concrete cracks exposed in the later operation stage of steel lined reinforced concrete penstocks.The study on measures of crack restraint of steel lined reinforced concrete penstock is carried out.Proposing to “upgrade” ordinary concrete with steel-fiber concrete around steel-lined reinforced concrete pipes.The axial tensile test of steel fiber reinforced concrete is also designed and carried out.Study on the influence of the addition of steel fiber can advance the structural cracking load and restrain the expansion of cracks and reduce the width of the cracks.Combining large-scale model test results of steel liner reinforced concrete penstocks of a hydropower station.Through nonlinear finite element method to study on the bearing performance and cracking control effect of this steel-lined reinforced concrete pipe after the addition of steel fiber.The main contents are as follows:1.Based on structural characteristics and stress characteristics of steel lined reinforced concrete pipes to design different addition of steel fiber reinforced concrete specimen.Then determine the form of the specimen,clamping methods and test batch.Putting forward the forming specimen and steel processing steps for the test process.According to test requirements determine the loading method and select the testing machine and data acquisition system.For the test difficulties proposed a solution: eccentricity problem,the accuracy of pasting strain slice,strain collection problem and measurement of steel strain on the crack.At last measured the test data of reinforced stress,crack spacing and crack width of reinforced concrete specimen.Study on the effect of different the volume fraction of steel fiber on the cracking load of specimens.Analyzing the crack development process of reinforced steel fiber reinforced concrete specimens.Study on the influence law of steel fiber incorporation on crack spacing,number of cracks and etc.Study on the relationship between steel stress and crack width at different steel fiber volume ratios.Comparing and analyzing with the effects law of different reinforcement ratios and steel fiber volume fractions on crack width.2.Through nonlinear finite element method to study the bearing performance of steel liner reinforced concrete penstocks of a hydropower station.Mainly study on the cracking load,the steel stress and the crack width of with different steel fiber volume.The incorporation of steel fibers can not only significantly improve the crack resistance of the structure but also reduce the damage area of outer concrete of pipeline and limit the rate of development of cracks.It has a very favorable effect on the crack width control of the structure...