Experimental Study On Pure Shear And Bending Shear Mechanical Properties Of Concrete Filled Corrugated Steel Tubues

The steel-concrete composite structure has been widely used at home and abroad because of its superior mechanical properties and economic benefits,but its corrosion problem becomes more and more serious with the increasing complex application environment.In order to solve the corrosion problem,the concrete-filled galvanized corrugated steel tubular component came into being.The galvanized corrugated steel pipe can provide good anti-corrosion ability for this kind of component,and also can provide strong restraint to the internal core concrete,so it is suitable to be used as pier components in viaduct,urban overpass and industrial and civil building structures.However,in practical engineering,short columns or ultra-short columns with relatively small shear span may be formed,and shear failure may become the control condition for failure of component and even structure.Under the action of large concentrated load or strong earthquake,the key parts of high-rise structure and the girder bridge system are subjected to the shear action obviously,which leads to the fragility and poor ductility of the component shear failure,and the serious structural continuous collapse,and then brings the loss of life and property.Therefore,it is very important to study the shear behavior of concrete-filled galvanized corrugated steel tubular components.At the same time,it can also lay a foundation for the subsequent study of the mechanical properties of components under complex load coupling action.In this thesis,the pure shear and bending shear mechanical properties of concretefilled galvanized corrugated steel tubular components are studied experimentally and theoretically,The specific contents include:1.The pure shear tests of 6 concrete-filled galvanized corrugated steel tubular components and 3 concrete-filled steel tubular components were carried out to monitor the trend of bearing capacity and angle of these two types of components with mid-span load under shear action,and to compare the overall deformation and failure modes of the two types of components,The results show that the corrugated steel tube can provide sufficient restrains for the inner core concrete and steel,and the corrugated steel tube members still have better ductility than the corrugated steel tube members under the condition of small shear span ratio,which can effectively delay the brittle shear failure.2.The flexural shear tests of 12 specimens of concrete-filled galvanized corrugated steel tubular were carried out to compare and analyze the test phenomena and failure modes under different shear span ratios.The results show that: when the shear span ratio is less than 0.2,the specimen shear dislocation is obvious,and the shear failure mainly occurs;when the shear to span ratio is between 0.2 and 2.0,the bending shear failure occurs to the specimen,with the increase of the shear to span ratio,the failure form of the specimen becomes more and more close to the bending failure;when the shear span ratio is greater than 2.0,the specimen is subjected to bending deformation,and the bending deformation becomes more and more obvious as the load is applied step by step.3.Based on the calculation method of the shear capacity of components in the relevant standards of reinforced concrete in China,the United States and Europe,the practical calculation formula of the shear capacity and the flexural shear correlation for concrete-filled galvanized corrugated steel tubular components are put forward.The formulas for calculating the shear capacity of concrete-filled galvanized corrugated steel tubular components and the correlation between bending and shear are verified respectively.