| The consumption of fine aggregate of concrete is enormous in engineering construction,river sand is used as the fine aggregate of concrete in china at present,with the increase of construction quantity,this will inevitably lead to a shortage of river sand resources,especially in coastal areas,river sand resource itself is quite scarce,and the sea sand resources are very rich,but the chloride contain is high in unwashed sea sand,this is the main reason for restricting its application.Stainless steel has good corrosion resistance,besides,it has the advantages of good ductility and beautiful appearance,the above two kinds of materials combined into sand concrete filled circular stainless steel tubular composite column in this paper,the mechanical properties of unidirectional bias are investigated,the main contents are as follows:(1)Unidirectional eccentric compressive test of 42 concrete filled circular stainless steel tubular specimens has been carried out,the main parameter is:a)core concrete type;b)loading eccentricity;c)slenderness ratio;d)concrete strength grade,the parameters of the test results are analyzed in detail,the failure modes,load-displacement curves,load-strain curves,the lateral deflection curve under different loads,the longitudinal strain distribution of the cross section under different loads,ultimate bearing capacity and ductility of specimens are included.Test results show that,compared with ordinary concrete filled circular stainless steel tube in the same conditions,the ultimate bearing capacity of unwashed sea sand concrete filled circular stainless steel tube shows a decreasing tendency,ductility shows an increasing tendency;the ultimate bearing capacity of washaed sea sand concrete filled circular stainless steel tube mostly shows an increasing tendency,ductility shows a decreasing tendency.The ultimate bearing capacity of specimens decreases with the increase of loading eccentricity and slenderness ratio of specimens,and increases with the increase of strength grade of concrete.The ductility of specimens increases with the increase of loading eccentricity,and decreases with the increase of slenderness ratio and strength grade of concrete.(2)The ultimate bearing capacity of the specimens is calculated by using the national standard "Technical code for concrete filled steel tubular structures" and "Technical specification for concrete-filled steel tubular structures" which is the standard of construction in Fujian province.Calculation results show that,the above two standards can be used for the design of one-way eccentric members of concrete filled circular stainless steel tubes,among them,"Technical code for concrete filled steel tubular structures" is more consistent,"The technical specification for concrete-filled steel tubular structures" is relatively conservative.(3)The finite element method is used to simulate the concrete filled circular stainless steel tube,the applicability of the existing model of concrete filled circular stainless steel tube is verified,the parameters of the ultimate bearing capacity of the specimens are supplemented and analyzed,including the steel ratio,slenderness ratio,loading eccentricity and the strength of core concrete.The analysis results show that,for the unwashed sea sand concrete and washed sea sand concrete circular stainless steel tube,the finite element model of the existing ordinary concrete filled circular stainless steel tube is also applicable.The ultimate bearing capacity of specimens is positively related to the steel content and the strength of concrete,and negatively related to the loading eccentricity and the slenderness ratio of specimens. |
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