Experimental Study On The Centrically Axial Loaded Src Columns Under Fire Including Whole Process Of Heating And Cooling

In recently years, Steel reinforced concerte structures are more and more been used in high buildings because of it has many advantages, such as higher bearing capacity, superior performance of earthquake resistance and advantageous economic benefit. A lot of research work including experimental study and theoretic analysis has been done on the behavior of SRC columns under static loading and seismic action, but just a little research work has been done about the behavior of SRC columns under fire. Although pretected by the outer concrete, fire resistance of SRC columns is not as good as we expected because of its high steel ratio and tendency of spalling. It is necessary to study the behavior of SRC columns under/after fire detailly, which can be served as a basis for the fire design and performance evaluation after ireexposure.Experimental study and theoretic analysis on the behavior of SRC columns under fire including heating and cooling process have been done. Main contents are as follows:Firstly, tests on the fire resistance of centrically axial loaded SRC column under standard fire were conducted. One is 4-side heated and the other one is 3-side heated. Four tests on behavior of SRC columns under fire including the whole process of heating and cooling have also been done. Temperature field of the columns, fire resistance, deformation characteristic and surplus bearing capacity were observed. Effect of fire load ratio and heating time ratio on the bearing capacity of SRC columns after fire exposure were discussed.Secondly, by reviewing the relevant literatures and comparing the research results of different researchers of foreigners and Chinese, thermal and mechanical properties of concrete and steel at high temperatures are selected. A general finite element software ANSYS is utilized to establish the model for calculating the temperture field and mechanical performances of axial compressive steel reinforced concrete columns during the whole period of fire.Thirdly, theoretic analysis on the behavior of SRC columns under action of fire including heating and cooling process were been done. Comparision of the results to the test one was conducted.Eexperiment results showed that fire load ratio and heating time ratio have great influence on the surplus bearing capacity after fire exposure. From the comparision we can see, the results of finite element analysis coincide well with that of tests.