Study Of Ductility Of New Encased Steel-concrete Composite Beam

New encased steel-concrete composite beam is a new type of composite beam which combines the U-section steel and the concrete beam together by means of filling the U-section steel with concrete and laying out the studs along the steel plate.The resistance to overturning and the shear capacity of the encased steel-concrete composite beam are well improved.It has inherited the former advantages and overcome the former shortcomings with the features of simple construction,good fire resistance performance,high manufactural efficiency and cost saving with great significance in research and engineering prospect.This study was on the basis of the static loading test of the new encased steel-concrete composite beam and made use of the finite element analysis which had verified the effectiveness of simulation.The ductility performance and mechanical characteristics of that were highly studied in this paper.Major research contents are as follows:(1)The bending test on five high-strength steel-encased composite beams was conducted.The experiment phenomena,strain distribution along the section height,load-deflection curves and moment-curvature curves were studied with data analysis method to explore the ductility performance and mechanical characteristics of the encased steel-concrete composite beam.(2)The study had put forward the flexural capacity formula,the vertical shear capacity formula and the longitudinal shear capacity formula on the basis of the full shear connection composite beam under static loading to analyze its mechanical performance theoretically.(3)The element attributes,modeling process and simulation steps of the finite element analysis was introduced in detail.The results of simulation was validated in loading,deflection,stress and test phenomena compared with the test results.(4)As to the parametric transformation of finite element analysis,the effect of concrete strength, steel yield strength and flange width on the mechanical characteristics and the deflection ductility was analyzed quantitatively by the analysis of the computer simulation.The connection of the relative depth of compressive zone and ductility was explored theoretically to provide foundation for the study of parameters.