Study On Stiffness Theory Of Connectors And Negative Moment Area Performance Improvement In Steel-concrete Composite Beam

As a novel structure,steel-concrete composite girder has lots of advantages such as excellent mechanical behavior,thrift of economy,easy construction and so on.These advantages are definitely according with the development of modern society.The comprehensive value of the new structure has attracted more and more attention,nowadays,most architecture are applied with the novel structure.The interface between steel and concrete has many types of connection in steel-composite girder.The most widely used connector in construction is bolt.However,in steel-concrete composite girder,the damage of the connectors often appears on the head of nail.This phenomenon proves that due to the circle head of the nail,the concrete around has a stress concentration appearance,meanwhile,the quality of the concrete right beneath the nail is not so good.Therefore,it is necessary to explore new shear connectors to improve the stress state of the joints and surrounding concrete.This paper will put forward a new type of shear connectors.The steel-concrete composite beams in the structure stress in the material,carry out their duties,the upper part of the concrete is under pressure,and the lower steel beam is mainly subjected to tension,it can maximize the advantages of two kinds of materials,to make the best use of the objective.But in the continuous composite beam,the negative moment region still adopts the conventional combined structure,The upper structure is made of concrete,and the lower part is made of steel beam,At this time the concrete will bear the tension,the steel beam will bear the pressure,this kind of stress situation regardless of the steel beam and the concrete will be extremely disadvantageous.At present,in the engineering application,most of the concrete bridge deck is applied to achieve a certain stress,But tends to make the negative moment area of the bridge plate cracks more durability is poor,the lower part of the steel beam easily buckling instability,the construction process is also more complicated.In view of this situation,this paper put forward three kinds of schemes.And we carry out the numerical analysis for it.In this paper,based on the consideration of material and boundary conditions nonlinearity,The general finite element analysis software ABAQUS was used to analyze the above two solutions,,get the following conclusion:1)The new shear connector is more uniform than traditional stud connector of the force.It could preferably solve problems of the poor quality of the concrete cap and the uneven stress of stud.The improved new shear connector can not only solve the problem of drawing but also is more uniform of the force.And it is close to the traditional stud connector about the shear stiffness at the same time.2)improved negative moment region of the structure can better solve the problem,that Upper tension and lower compression in steel-concrete composite continuous beams in the negative moment region.This is consistent with the negative bending moment area of the force requirements,and compared to the traditional construction is more simple and convenient construction.Among them,one of the program is a more conservative,three of the program is more economical.