Finite Element Analysis On Shear Performance Of Steel Reinforced Concrete Column With Diaphragm

In recent yeas,high-storeyed buildings and over high-storeyed buildings increased gradually,steel reinforced concrete structure has been widely used.Earthquake damage investigation indicated that the collapse of buildings dued to the brittle fracture of column because of the insufficient shear bearing capacity especially of the short column.Therefore the shear bearing capacity of the columns is the key to ensure the safety of structure under the earthquake.Due to the existence of steel,opening holes in steel web to through the stirrup increased the difficulty of construction.In order to simplify the construction,a new form of steel reinforced concrete column section had been proposed,using diaphragm instead of stirrups,to avoid weakening of the web because of opening holes in the steel.In order to verify the effectiveness of simplifying construction by using diaphragm instead of stirrups,quasi-static experimental research,theoretical analysis and finite element simulation analysis had been taken.The main contents include:In this paper,twenty-four specimens under two kinds of shear span ratio with three different cross section forms had been designed for low cycle loading test.The strain of the key parts of the specimen at different loading times were analyzed.The writer founded the finite element model of ordinary steel reinforced concrete column and steel reinforced concrete column with diaphragm using ABAQUS,and studied shear performance of it.Firstly,we compared the numerical analysis results and the test's results to verify the reliability of finite element model.The curve from finite element analysis and failure pattern agreed well with that from tests,which verified the conclusion.Then,we used the finite element model to complete a series of studies with different parameter-shear span ratio,stirrup ratio,thickness of diaphragm,interval of diaphragm,shape and area of diaphragm.Experimental results and finite element simulation results showed: Hysteresis curve of specimens with diaphragm and specimens with other forms of cross section were full fusiform,each specimen of energy dissipation performance are basically the same.Specimens with diaphragm could meet the ductility requirements of structural and energy dissipation.At the same stirrup ratio,with the increase of shear span ratio,the shear capacity of steel reinforced concrete short column had been reduced.When the shear span ratio increases to a certain degree,the shear bearing capacity is almost not influenced by it.At the same shear span ratio,with the increase of stirrup ratio,the shear capacity of steel reinforced concrete short column had been increased.Diaphragms could transfer the force to the adjacent steel flange and web,make the pressure equilibrated on steel,improve the integrity of specimens and ensure the bearing capacity.Plate thickness and decreases baffle spacing has certain influence on the shear bearing capacity,but the impact is not obvious.Increasing the partition area,changing the plate shape will improve the peak load,but energy dissipation capacity and ductility is worse than the original shape variation.The calculation algorithms of Technical specification for concrete structures of steel(YB9082-2006)was safe,the computing algorithm of Technical code for steel reinforced concrete composite structures(JGJ138-2001)had good applicability.In this paper,on the basis of Technical code for steel reinforced concrete composite structures(JGJ138-2001),the practical formula of steel reinforced concrete column with diaphragm is put forward.Using diaphragm instead of part of the stirrups is a conventional method that can avoid weakens the web plate because of opening holes in steel web,meet the component capcity and ductility and and it can also be a reference to the design of steel reinforced concrete column in future application.