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

The spatial composite effect of slab has an important influence on the mechanical performance of steel-concrete composite frame structure.In order to study the composite effect of slab conveniently,the concept of effective width of floor slab is introduced.At present,the research on the effective width of the slab mainly focuses of the simple branch and the continuous composite beam at home and abroad.But the experimental and theoretical research on the rigid combined connection is relatively few,especially the study on the effective width of the slab in the weak-axis rigid composite connection has not been reported.Therefore,this paper studies and analyzes the design method of the effective width of the slab in the weak-axis rigid composite connection with box-shaped panel zone.It studies the influencing factors of the effective width of the slab under the action of the limit positive and negative bending moment,puts forward the relevant theoretical calculation formula,and verifies the accuracy of the formula by a large number of numerical analyses.The formula is reviewed by the flexural bearing capacity of Beam end,and its rationality is verified.And the applicability of the proposed formula to the calculation of the effective width of the strong-axis connection,recycled concrete and light aggregate concrete slab is verified.The conclusions are as follows:(1)For the weak-axis rigid combination of with box-shape panel zone,the influence of beam span on the effective width of beam end slab is negligible under the action of limit positive and negative bending moment,which indicates that the effective width of slab is only related to the key section.At present,the calculation formula of the effective width of the slab given in the specification at home and abroad is not suitable for the weak-axis rigid combination connection with box-shaped panel zone of I-shaped column.(2)Under the action of the limit positive bending moment,the main factors affecting the effective width of the slab in the weak-axis rigid combination connection with box-shaped panel zone are the actual width of the floor,the flange width of the weak-axis beam and the height of column.Under the action of the limit negative bending moment,the main factors affecting the effective width of the slab in the weak-axis rigid combination connection with box-shaped panel zone are the actual width of the floor,the flange width of the weak-axis beam,the flange width of the orthogonal beam,the size of column,reinforcement rate of floor and yield strength of steel bar.(3)For the calculation of the effective width of the slab under the action of limit positive and negative bending moment,the suggested formula proposed in this paper is effective,the error is within 10%,and the slab spatial composite effect can be reasonably considered in the structural design,and there is enough safety reserve.(4)The calculation formula for the effective width of the floor under the action of the ultimate positive bending moment proposed in this paper is not suitable for the strong-axis rigid connection,but it is barely available for the strong-axis rigid connection under the action of the limit negative bending moment.The calculation formula for the effective width of the floor under the action of the ultimate positive and negative bending moment is applicable to the calculation of the effective width of the recycled concrete slab and the light aggregate concrete slab in the weak-axis rigid composite connection.