| Funded by the Chongqing Natural Science Foundation of Chongqing “Research on the Behavior and Computational Theory of Prefabricated Composite Beam Double Non-coupling Structures”(cst2018jcyj AX0509)Next,in order to study the non-linear change law and deformation analysis method of the flexural rigidity of the assembled composite beam with the clustered key group,the test parameter is carried out with the clustering degree(defined as the number of shear keys in a single row of reserved holes/the number of shear keys in the whole beam)The prefabricated group nail composite beam loading test,the nonlinear stiffness and deformation calculation equations of the prefabricated composite beam from loading to failure are deduced,the deformation influence parameter analysis of the prefabricated composite beam is carried out,and the nonlinearity of the prefabricated composite beam is discussed in combination with finite element.The mechanical characteristics of behavior.The main research work is as follows:1)The static loading test of assembled composite beams with 5 kinds of bundle degree was undertaken,and the failure mode,load-deformation curve,load-slip curve and steel and concrete strain distribution of the test beam were analyzed and obtained.The results show that the beams in this test are all bending failures;the interface slip along the beam length shows a trend of "large middle and small ends";the larger the bunching degree,the larger the slip,and the larger the mid-span deformation,but the slippage is The effect is more significant than the deformation effect.2)According to the characteristics of load-displacement curve,slip influence and material nonlinearity,the force and deformation process of assembled composite beams can be divided into three stages: elastic stage(divided into linear elastic and elastic stages),elastoplastic stage and plastic stage;By deriving the stiffness equations at each stage separately,the stiffness and deformation calculation method of the assembled composite beam during the whole process of force is finally established.(1)Regardless of the effect of clustered discontinuous shear connection,the stiffness equation of the prefabricated composite beam at the linear elastic stage is established based on the assumption of continuous uniform slippage of the interface;(2)Considering the influence of the intermittently arranged shear keys on the slip distribution on the stiffness,the stiffness equations of the assembled composite beam in the elastic stage are deduced based on the slip effect additional curvature method and the slip reduction equivalent stiffness method.For comprehensive accuracy and ease of calculation,the latter is generally called for calculations.(3)By dividing the assembly-type combined beam into the shear connection and the non-shear connection section,considering the steel and concrete parts into plasticity,based on the elastic theory,the rigidity equation of the cross-section of the two sections is established,and the equivalent stiffness equation is established by assuming that the corners of the deformation are equal,and the equivalent stiffness method is used.3)Using the aforementioned assembly-type combination beam deformation calculation method,the effects of cluster degree,concrete slab to steel beam height ratio,width ratio and material strength ratio on the deformation of the combined beam are analyzed,of which the height ratio is the most significant,the concentration has a certain effect on the deformation of the elastic plastic stage,the higher the strength ratio,the better the delay of the combined beam4)Carrying out numerical analysis of the whole process of fabricating composite beams,study the influence of the nonlinear mechanical behaviors of steel beams,studs and concrete slabs on the overall stiffness and deformation of composite beams during the loading process,and discuss the nonlinear mechanical behaviors of prefabricated composite beams and Its physical meaning. |
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