| With the extensive application of composite materials,there have also been rich changes in construction engineering components.Among them,stainless steel tube concrete columns are widely used in civil engineering structures.Compared with ordinary concrete-filled steel tube concrete,stainless steel concrete-filled steel tube columns have better aesthetics and corrosion resistance.Therefore,many projects use a combination of stainless steel tubes and concrete.It is common to serve in a corrosive environment.At present,there are more studies on the mechanical properties of stainless steel tube concrete and corrosion of stainless steel,but less research on stainless steel tube concrete in acidic corrosion environment.In order to make up for the gap in this paper,the previous research on the axial compression of stainless steel tube concrete and stainless steel.On the basis of corrosion research,the axial bearing capacity of stainless steel tube concrete under acid corrosion environment was carried out.The thesis mainly completed the following contents:(1)The pouring and maintenance of 117 stainless steel concrete filled steel tube columns were completed,and an acid solution was prepared to corrode 108 stainless steel concrete filled steel tube columns.The experimental phenomena after corrosion were observed and analyzed.After the corrosion was completed,all the specimens were subjected to the axial static load test.Based on the test phenomena observed after loading,the typical failure modes of the specimens are summarized.Research shows that as the acidity of the solution increases,the bearing capacity of the specimens also decreases.When the corrosion time is longer,the corrosion is relatively serious,and the bearing capacity of the specimen decreases,but the overall decrease is not large,mostly within 10%.(2)On the basis of the test,based on the load-displacement curve,a series of test data such as the initial stiffness,ductility coefficient,and ultimate bearing capacity of the specimens were obtained.By studying the solution p H,corrosion days,concrete strength,and steel pipe wall thickness The influence of these four variables on the test results focuses on the analysis of the effects of solution p H,corrosion days and mechanical properties.Research shows that the bearing capacity of wall thickness is closely related to the strength of concrete.The higher the compressive strength of core concrete,the greater the ultimate bearing capacity of the specimen.(3)The stiffness degradation rule of the specimen after acid corrosion was analyzed by introducing the stiffness ratio.The initial stiffness of most specimens after corrosion by acid solution was lower than that of untreated specimens.,Of which the largest decline reached 47%.After corrosion,the ductility of most specimens is lower than that of uncorroded specimens.As the number of corrosion days increases,the ductility of specimen decreases,and it shows a linear downward trend.As the acidity increases,the ductility of specimens also decreases.When the acidity is weak,the ductility of the specimen is relatively close,indicating that the weak acid environment has little effect on the ductility of the specimen.(4)Based on the previous calculation formulas of the axial compressive bearing capacity of concrete-filled steel tubes and the test data of the bearing capacity of each specimen,the SPSS software was used to return the acid corrosion attenuation coefficient,and combined with the previous formula,the stainless steel tube concrete was obtained.The formula for calculating the ultimate bearing capacity of the specimen after acid corrosion is checked and the formula is checked to ensure that the formula is accurate and has sufficient safety reserve.This provides a reference for the study of bearing capacity of stainless steel pipe concrete columns after corrosion. |
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