Study On Effective Width Of Lightweight Aggregate Concrete Slab Of Weak Axis Composite Connection With Box-shaped Panel Zone Of I-section Column

In the composite beam,the interaction between the slab and the steel beam is realized by the shear joint.For the complete shear-resistant composite beam,the stress distribution in the slab is very complicated because of the shear lag effect.In order to simplify the calculation,the stress distribution in the slab is very complex.The concept of effective slab width is introduced,and the effective width of slab is used to calculate the effect of slab combination effect.A great deal of research has been done at home and abroad on the influence of the effective width of the slab and the calculation method,but the research on the effective width of the slab in the rigid composite connection is mainly focused on the strong axis connection of I-shaped columns,but the research on the effective width of the slab in the rigid composite connection is basically focused on the composite beam.Few studies on weak-axis connections of I-shaped columns.In practical engineering,the connection of weak axis direction of I-shaped column is as common as strong axis,so finding a design method suitable for the effective width of floor slab in rigid composite connection of weak axis has high scientific significance for engineering design and scientific research.On the basis of the weak-axis rigid connection of I-shaped column in box joint domain,the lightweight aggregate concrete floor slab is applied to the new type of weak-axis rigid composite connection.The finite element software ABAQUS is used to simulate the weak axis rigid composite connection of concrete floor with lightweight aggregate.Firstly,the variable parameters of the effective width(the size of beam and column,the size of floor,etc.)related to the rigid composite connection of lightweight aggregate concrete floor under positive and negative bending moment are analyzed.After analyzing the main influencing factors under the action of the limit positive moment and the limit negative moment,the corresponding effective width of the slab is fitted out by using MATLAB software.The calculation formula,the applicability and reliability of the formula are discussed,and compared with the calculation formula of the effective width of the floor in the national codes.Finally,the formula proposed in this paper is checked by using the calculation formula of the bending bearing capacity.The main conclusions are as follows:(1)the main influencing factors of effective width of lightweight aggregate concrete floor under the action of ultimate positive bending moment are column height,weak axis beam flange width,strong axial beam flange width and floor actual width,and the main influencing factors are column height from large to small.The flange width of the weak axis beam,the flange width of the strong axis beam and the actual width of the slab;The main influencing factors under the limit negative bending moment are column effective width,weak axis beam flange width,strong axis beam flange width and floor actual width.The main influencing factors are column effective width and floor actual width from large to small,and the main influencing factors are column effective width,weak axis beam flange width,strong axial beam flange width and floor actual width.The flange width of strong axis beam and weak axis beam.(2)in this paper,it is proposed that the formula for calculating the effective width of the slab under the action of the ultimate negative bending moment is equally applicable to both the strong axis and the ordinary concrete.However,the formula for calculating the effective width of the slab under the action of ultimate positive bending moment is not suitable for strong axial connections and composite rigid connections of ordinary concrete floors.(3)under the action of positive and negative bending moment,the formula for calculating the effective width of slab has high precision and the error is less than ±10%;By checking the bending bearing capacity,it is found that there is enough safety reserve in engineering design according to the formula for calculating the effective width of the slab proposed in this paper.