Study On Evaluation Of Seismic Damage For Castellated Composite Beam

Castellated composite beam is a member which consists of concrete slab and cellular beam.MWhen the castellated beam and the concrete slab are combined into a whole,it can maximize the performance of two materials.Therefore,the application of castellated composite beam is more widely.Due to stress migration in the hole of web,the distribution of stress,law of plastic development and the definition of failure mode will change.Although,there are a lot of theoretical analysis and experimental research about castellated beam and composite beam at home and abroad,but there are few study of failure mode,limit of depth-thickness ratio and damage index under cyclic load,which greatly limits the application of castellated beam and composite beam in practical project.So this paper studies and analyzes the problem,the main contents include:The finite element simulation analysis of castellated beam and composite beam has been done experiments already,and the results are compared with the test results.The correctness and rationality of the finite element model are verified,which lays a foundation for the analysis.Establish the model under bending moment,shear moment and bending-shear moment failure of castellated beam under low cyclic loading.Then study the material damage process,ultimate bearing capacity and normal stress proportion influence on different web thickness ratio,hole high thickness ratio,flange width thickness ratio and other parameters.According to the large number of simulation analysis,the web thickness ratio is about 38,hole high thickness ratio is about 24,flange width thickness ratio is about 8,can be a good study of castellated beam under bending moment.When the web thickness ratio is about 44,flange width thickness ratio is about 8,shear span ratio at about 1/4,can be a good study of castellated beam under shear moment.And when the web thickness ratio is about 47,hole high thickness ratio is about 30,flange width thickness ratio is about 8,can be a good study of castellated beam under bending-shear moment.In the same way,the castellated composite beam models are established for simulation analysis.The results show that the web thickness ratio is around 42,flange width thickness ratio is around 7,can be a well study of castellated composite beam under bending moment.When the web thickness ratio is around 42,flange width thickness ratio is around 8,can be a well study of castellated composite beam under shear moment.And when the web thickness ratio is around 47,flange width thickness ratio is around 8,can be a well study of castellated composite beam under bending-shear moment.Characteristics of damage development based on material,there will be classifications of different failure modes of castellated beam and composite beam.The failure mode under bending moment of castellated beam and composite beam is the buckling of the flange.The failure mode under shear moment of castellated beam and composite beam is the hole angle tearing.The failure mode under bending-shear moment of castellated beam and composite beam is the "S"failure of the inter hole web.Because of the relationship between damage information of material and phase change of castellated beam,the damage index D0 of the seismic damage of castellated beam and composite beam is applied by using the single parameter model.It is very significant between D0 and web thickness ratio,hole ratio,high thickness of flange width thickness.For the future,it has a great significance for seismic design and reliability of structure,and it provides the theoretical basis for practical project.