Study On Effective Width Of Recycled Aggregate Concrete Slab Of Weak-axis Rigid Composite Connection With Box-shaped Pannel Zone Of I-section Column

In the design of steel-concrete composite beams,the stress distribution in the plates is complicated due to the shear lag effect,in order to simplify the calculation,the concept of effective width is introduced.Most of the researches on effective width at domestic and foreign was mostly directed to the composite beam.And the research on the effective width of the composite beam steel frame joints was mainly concentrated on the strong-axis bending connection,while for the weak-axis composite joints,limited research has been done so far.The connection frame will be affected by the positive bending moment and the negative bending moment under the action of earthquake,and the stress distribution is more complex.Therefore,this paper is aimed to give a more rational method to calculate the effective flange width of rigid composite connection under the action of ultimate bending moment,in order to provide design reference for experimental and engineering applications.The recycled aggregate concrete based on box-shaped region rigid composite connection for weak-axis of I-section column was assessed using finite element modeling by ABAQUS.Firstly,the variable parameters such as the size of beam,the size of column,the size of concrete slab,the yield strength and ratio of longitudinal reinforcement,and material properties of recycled aggregate concrete were analyzed for the factors that may affect the effective width of the joints under the action of ultimate bending moment.The corresponding calculation formula was fitted by MATLAB according to the main influencing factors,and the formula was reviewed by the bending capacity.The Chinese current code refers to steel-concrete composite structure's effective width was compared and analyzed among other countries and equations proposed by author.At last,the applicability of the formula in the strong-axis and ordinary concrete was analyzed.The main results are summarized as follows:(1)The main factors that influence the effective width are the height of the column,the thickness of the concrete slab,the width of the steel beam flange in orthogonal direction and the width of the flange of the strong-axis beam in order of correlation degree under the action of the ultimate positive bending moment.The main factors that influence the effective width are the effective size of the column,the actual width of the concrete slab,the span of the steel beam,the yield strength of longitudinal reinforcementthe,the ratio of longitudinal reinforcement and the width of the flange of the steel beam in order of correlation degree under the action of the ultimate negative bending moment.(2)The effective width calculation formula proposed in this paper has good accuracy,and its relative error does not exceed ±10%,and the results of the review of the flexural capacity show that the formula proposed in this paper has sufficient safety reserves.(3)The effective width calculation formula proposed in this paper is not ideal for the applicability of the effective width calculation of ordinary concrete connections under the action of ultimate positive bending moment and strong-axis connections,but it has better applicability to the calculation of effective width of ordinary concrete connections under the action of ultimate negative bending moment.