Nonlinear Analysis And Section Optimization Design Of Steel-concrete Continuous Composite Beam

Steel-concrete composite beams is a new type of structure that skillfully and reasonably combines the steel and concrete into a whole,it have the advantages of steel structure and concrete structure,and just rightly abandon the shortcomings of the two,has distinctive comprehensive benefits.At present,the research on steel-concrete composite beam has made great progress,but the study on the deformation and bearing capacity of composite beams with the consideration of interface slip is still not comprehensive enough and needs to be improved.Therefore,the research on the nonlinear behavior of composite beams with the consideration of slip effect is of far-reaching significance.Steel-concrete composite beams have been widely used in the field of urban construction and bridge reinforcement in our country because of its economical and reasonable structure,therefore,it is important and urgent to reasonably select the section size of composite beams in order to reduce the cost of composite beams.In view of the above,the following work is done in this paper:?Considering the material properties of the composite beam parts and the slip of the steel beam and concrete slab interface,a parametric finite element model is established for the nonlinear analysis of steel-concrete continuous composite beam by ANSYS12.0.?Analysing the distribution characteristics of interface slip and deflection along beam and the distribution characteristics of load-slip curve,load-deflection curve and section strain curve of steel-concrete continuous composite beams,on the basis of this study,the influence law of degree of shear connection,concrete strength and steel beam intensity on the nonlinear behavior of composite beams is studied.The results show that the influence of degree of shear connection on the nonlinear behavior of composite beams is great,The difference of stiffness of elastic stage of composite beams with different shear connectors is little,the stiffness of plastic stage is relatively large,showing that using partial shear connection composite beam in the practical engineering is feasible;the effect of concrete strength on the nonlinear performance of composite beams is small;the effect of steel beam intensity on the nonlinear performance of composite beams nearly can be neglected.?Optimization analysis of steel-concrete composite beam section.Firstly analysing the variation law of stress and deflection under different web height and web thickness,flange thickness of steel beam and concrete slab thickness,and then take these four parameters as design variables,the maximum deflection of the composite beam,the maximum tensile stress of the steel beam and the maximum compressive stress of the concrete slab as state variables,the construction cost of composite beams as the objective function,in view of ANSYS parametric design language APDL,selecting zero-order optimization method,and composing structural analysis and optimization control file,conducting optimization analysis of steel-concrete composite beam section.after optimization,composite beam cost from the initial design of 817.24 yuan down to 505 yuan,only 61.79% of initial design,saving 312.24 yuan,the optimization effect is obvious,and the project cost is significantly reduced.The research results in this paper can further improve the design theory of composite beam,are beneficial to the spreading and application of the steel-concrete continuous composite beams.