Research On The Bending Behavior Of Centrifugal Concrete Filled Steel Tubular Piles

As a new type of precast pile, the centrifugal concrete filled steel tubular pile makes full use of the high compressive strength of concrete and the strong tensile ability of steel tube, exerting advantages of combination, and showing excellent mechanical properties, which gets the favor of engineering design personnel gradually. Therefore, researching on its mechanical properties plays a positive role in promoting the market development in the field of precast piles.The bending properties of centrifugal concrete filled steel tubular piles were researched in this paper. Firstly, the bending behavior of three centrifugal concrete filled steel tubular piles and one pre-stressed centrifugal concrete filled steel tubular pile was researched by testing. Respectively the deformation law of them under the action of bending moment was explored in macro and micro, and the effect of the configurations of pre-stressed steel bars on its flexural behavior was analyzed contrastively. Then, the finite element simulations for the bending tests of centrifugal concrete filled steel tubular piles were carried on and the effects of the steel tube wall thickness, the concrete tube wall thickness and the outer diameter of piles on the bending bearing capacity were analyzed by adopting the method of orthogonal analysis. Finally, the bending bearing capacity of centrifugal concrete filled steel tubular piles were calculated and compared by using superposition theory and unified theory respectively, and a calculation formula of yield bending moment was deduced.After researching, the following conclusion can be got:the centrifugal concrete filled steel tubular piles showed good bending ductility and strong bending bearing capacity in the process of bending deformation, and the configurations of pre-stressed steel bars can improve the bending bearing capacity of them to a certain extent, but contribute nothing to improve the bending ductility; the outer diameter of piles is the main factor influenced the bending bearing capacity, and the steel tube wall thickness takes the second place, the concrete tube wall thickness takes the last; the calculated values of yield bending moment by deduced formula can fit well with the test values and simulated values.