Experimental Research on Bending Performance of the PEC Beams with Sinusoidal Corrugated Webs

Partially encased composite steel and concrete structure is referred to as the PEC structure, with the advantages of concrete structure and steel structure. The filling concrete can effectively improve the anti-flexural capacity of the steel, and the flange is formed by welding steel bars. The connecting rod enhances the constraints of the steel flange and concrete, thereby increasing the bearing capacity and stiffness of the structure. At present, there are many studies on platform PEC beams at home and abroad, but there are few researches on corrugated web PEC beams. In order to study the bending performance of the corrugated web PEC beams, the flat belt of the H-type steel is replaced with a sinusoidal corrugated web on the basis of the PEC beams, and the sinusoidal corrugated web PEC beam is proposed to study the bending performance, in order to provide reference for the practical application of this structure. Four sinusoidal corrugated web PEC beam specimens were designed, and the structural measures of reinforcement and weld form were changed respectively, and data such as deflection, slip and strain was collected by four-point bending loading test. Through load-middle span deflection curve analysis, bearing capacity analysis, deformation analysis, strain analysis, steel-concrete slip analysis, etc., the flexural strength, ductility, bond slip and other properties of four sinusoidal corrugated web PEC beam specimens were investigated. The advantages and disadvantages of different structures were compared.The test results show that the measured bearing capacity of the specimen is greater than theoretical bearing capacity, the yield bearing capacity and ultimate bearing capacity of the four structures have little difference, and the bearing capacity can be calculated by edge yield criteria and full cross-sectional plasticity criteria. There is no significant difference in bearing capacity and deformation between specimen with single fillet weld and double fillet weld between corrugated web and upper and lower flange, therefore the corrugated web of PEC beam and flange plate can be welded by single fillet weld. But the quality of the weld must be strictly ensured when making it. The strain of the main steel component along the web height of the beam was very small and did not reach the yield strain. The strain began to increase near the flange, and the strain at the flange increased sharply, indicating that the bending normal stress was almost completely borne by the flange, and the web strain of the main steel parts did not conform to the assumption of plane section. There is little difference in the slip amount of PEC beams of four kinds of structures. The slip at the support is small, and the maximum slip amount is basically within 1 mm. Due to serious concrete cracking in the mid-span belly, the slip quantity includes the influence of crack width, leading to much larger measured results. The data are for reference only. In the test, none of the sinusoidal corrugated web PEC beams of the four structural forms reached section failure in the end. The test was stopped due to excessive deflection, and the load-middle span deflection curve did not decline. The subsequent improvement will be considered, and the end of the test will be controlled according to the final failure of the specimen, so as to further explore the performance of the specimen.