Experimental Research on Flexural Behavior of Precast Thin-Wall Steel and Spun Concrete Composite Pile

Abstract

The flexural load-bearing performance prototype test has been made on the precast thin-wall steel and spun concrete composite pile with a diameter of 1000 mm (TSC pile). The load deflection curve and pile deflection curve at each loading step have been obtained. The bending test results show that the deformation of large diameter TSC pile experienced elastic, elastic-plastic and plastic three phases under the load of bending moment, the damage of pile was caused by the tension stress of steel in tension zone exceeded the yield strength, which belongs to the ductile damage. As for the TSC pile ultimate flexural bearing capacity, the measured value agreed with the theoretical calculation value, which shows that the existing thin-wall centrifugal concrete filled steel tube structure ultimate flexural bearing capacity calculation theory and method is suitable for large diameter TSC pile. Preface Precast Thin-wall Steel and spun Concrete composite Pile (TSC pile) is in the use of type Q235B or Q345B plate (strip) pouring of concrete filled steel tube made of crimping forming and welding, the centrifugal casting[1]. The compressive strength of concrete is not less than 80MPa, with a new pile products bear large vertical load and horizontal load. Concrete pile has the characteristics of high compressive strength, flexural capacity is weak; While the flexural capacity of steel pipe pile is strong, has good plasticity, But easy buckling occurs when the axial compression, loss of compression capability. TSC pile is a steel - concrete composite structure between steel pile and centrifugal concrete pipe pile, not only can give full play to the advantages of the both, can also overcome the shortcomings of its own when used alone[2]: With the inner wall of the concrete pipe, the outer pipe can enhance its stability ;and the inner concrete pipe with steel " confining effect", by the uniaxial stress state into three dimensional stress state, which greatly improves the compressive strength, With high anti-hammering capability, high penetration, pile sinking speed, good durability, pile quality, materials and low cost[3]. The TSC pile has been successfully applied to industry, electric power, transportation and other areas, commonly used in port engineering pile type of larger diameter, and by the wind, wave and other horizontal load, to put forward higher requirements of flexural performance of pile body. Therefore it is necessary to study the flexural behavior of large diameter pile TSC. Model test is usually the most useful method to study the pile loading behavior[4, 5].In this paper, the diameter 1000mm of TSC pile bending prototype test has been conducted, and the test is a research on the large diameter pile in TSC subjected to pure bending bearing capacity. Experimental Study of Pure Bending of TSC Pile