Research On Mechanical Properties Of Large Scale Block Recycled Concrete Filled Thin Walled Steel Tubular Long Column Under Axial Compression

Along with our country urbanization development, it appears a lot of constructionwaste, which has brought bad influence to the environment. How to use the constructionwaste has become a hot issue. Most of the research into the existing domestic is thatwaste concrete is used as coarse aggregate in new concrete. But it needs secondaryenergy consumption when waste concrete is damaged, which brings a negative impact.Concrete filled steel tube long column bearing capacity is not sensitive to the coreconcrete strength. So it can use large scale block in concrete, which makes moreefficient use of waste concrete. Based on the recycled concrete filled CFST on the basisof research results, the large scale block recycled concrete filled steel tube long columnunder axial pressure performance is studied.It designs12specimens, with slenderness ratio, steel ratio and block replace rate asparameter. It uses the orthogonal experiment to analysis of the effect of various factorson the bearing capacity of specimens and sensitivity. The results show that specimenexperiences elastic stage, elastic-plastic stage and plastic stage. Specimens eventuallydestroy are elastic-plastic buckling destruction, failure into a bow distribution. When theblock substitution rate is from20%to40%, the specimen ultimate bearing capacity isincreased by7%. When the steel rate is from8%to11%, the ultimate bearing capacityof the specimen is increased by7%. When the slenderness ratio is from55to60, theultimate bearing capacity is increased by12%. Through orthogonal test and analysis, itcan get that slenderness ratio is the most sensitive factor. Steel ratio is more sensitivefactor than block replace ratio. Specimen ultimate bearing capacity is decreased byincreasing slenderness ratio. Specimen ultimate bearing capacity is increased byincreasing of steel ratio. Specimen ultimate bearing capacity is decreased by increasingblock replace ratio.It simulates12specimens through finite element analysis software ABAQUS. Itcan get the good agreement between the experimental load-displacement curve and thesimulation load-displacement curve, which verify the reliability of the ABAQUS.It bases on the experimental data, and the aid of discipline at home and abroad specifications, such as AIJ procedure, America AISC regulations, Europe E4procedures,domestic CECS28:2012codes and DL/T5085-1999which are to calculate the specimenultimate bearing capacity. The calculation results show that domestic CECS28:2012has high precision, good agreement with the test results. Based on the existing researchof large scale block recycled concrete filled steel tubular short column, and consideringslenderness ratio effect, It uses linear regression to put forward formula of ultimatebearing capacity, to provide basic experiment basis for the establishment of the relevantspecification.