Numerical Analysis And Restoring Force Model Research Of Seismic Behavior Of Concrete Columns With Stainless Steel Bars

The steel corrosion always influences the durability of structure, especially in the environment of harsh corrosion attack of chlorides, such as seacoast, which decrease the service life of structures. The stainless steel rebar has good quality of anti-corrosion and could be adopted in concrete construction, so it has an extensive application on the bridge engineering in America, Europe and Japan in the past few years. Most of the published literatures are focused on the properties of stainless steel bar and its superior corrosion resistance, and little study is related to the dynamic mechanical properties, especially seismic performance of stainless steel reinforced concrete structures, which block the use of stainless steel rebar.In this paper, utilize the nonlinear OpenSees to build numerical model, and research some effects of seismic performance, such as degree of concretes, axial compression ratio and stirrup ratio. Then according to the analysis in this paper, the practical calculation method of stainless steel rebar reinforced concrete column of restoring force model has been got, the conclusions were as follows:(1) Based on the nonlinear procedure of OpenSees to build the numerical model of stainless steel reinforced concrete column. The error range is within10%by compare the numerical result hysteresis curve and skeleton curve with test result. Which showed that the numerical analysis model is be used to research the seismic performance.(2) The results that the seismic performance of the stainless steel reinforced concrete column showed that:①With the increase in grade of concretes strength, the peak of bearing capacity and hysteresis loop is larger. The load capacity at the strengthening stage enhances generation of rigidity of the stainless steel reinforced concrete columns drop slowly.②With the increase of stirrup ratio, the ductility coefficients are enhanced, and well ductility and energy dissipation capacity is shown.③When the axial compressive ratio less than0.5, With the increase of axial compressive ratio, the horizontal bearing capacity of columns tend to larger. But the horizontal bearing capacity of columns rapidly degradation after the axial compressive ratio get to0.5. With the increase of axial compressive ratio, the ductility of columns exhibit degradation, Which proof that larger axial compressive ratio is not benefit to the seismic of concrete columns. So the axial compressive ratio should be considered when seismic design.(3) Base on the test results the restoring force model of stainless steel rebar of columns is three-line curve of the stiffness degradation model. The restoring force model of stainless steel concrete columns based on the formula of restoring force model of conventional reinforced concrete is established, and regular of the model is studied. The skeleton curves that calculate by established formula are good agreement with the tests results.This research supported by Guangdong Provincial Nature Science Foundation (8152800001000004, S2011010001225)...