| Recently, super-high-strength concrete (SHSC) is more and more widely used because ofits good capability of resisting architecture needs of high-rise buildings, long-span. SHSC hasbeen shown to have advantages such as higher strength and better durability. But with theconcrete grade rising, SHSC becomes more and more brittle. The design of bearing columnsis the key to prevent architecture collapse in the earthquake. In China, the concrete strengthgrade is C15～C80 in the new applying "Code for design of concrete structures" (GB 50010—2002), and the concrete strength grade is C60 in the "Technical specification for steelreinforced concrete composite structures"(JGJ 138—2001). However, now there is very littleof correlative research on seismic performance of reinforcement super-high-strength concretecolumns, steel reinforced super-high-strength concrete. The contradiction betweenengineering requirement and current code or specification becomes more and more serious. Inorder to solve the above-mentioned problems, the following aspects are carded out in thisthesis:(1) First, the trail mixing of steel fiber SHSC and high modulus PVA fiber SHSC arestudied. Then the main mechanical properties of them are analyzed:①The splitting tensilestrength to compression strength ratio of C100 SHSC is about 1/20. The Young's modulus ishigher 30% than calculation according to current code formula.②when the steel fibervolume fractions ranged 0.5%～1.5%, steel fiber could apparently raise the parent concretecompression strength, being both above 10% improvements; it could significantly the splittingstrength, being 38.2%～91.9% improvements; the tensile strength to compression strengthratio increased 24.1%-73.5%.③when the PVA volume fractions ranged 0.17%～0.5%, thecompression strength increased slightly, only being 2%～8.2% improvements; PVA fibercould significantly the splitting strength, being 22%～46.7% improvements; the tensilestrength to compression strength ratio increased 15.3%～35.6%. The test results indicated thatthe steel fiber and PVA fiber had significant improving strength and toughness effect onsuper-high-concrete.(2) The seismic performance of SHSC columns subjected to low cyclic reversed lateralloads was studied. The shear span ratio, axial load ratio and the stirrup reinforcement ratiowere the main experimental variables affecting dynamic behavior of specimens. The failure patterns and shear force-displacement hysterefic characters were analyzed. The limit values ofthe axial load ratio and minimum stirrup characteristics values of columns are put forward tosatisfy definite ductility requirement. That limit values of the axial load ratio decrease 0.1than C80 columns of current code GB 50010—2002; however, the minimum stirrupcharacteristics values increase 0.02～0.05. According to the low limit values of experimentalresults, the suggested formula for calculating shear strength of SHSC columns is put forward.However the formula of current code GB 50010—2002 is too safer.(3) The seismic performance of steel SHSC columns subjected to low cyclic reversedlateral loads was studied. The shear span ratio, axial load ratio and the stirrup reinforcementratio were the main experimental variables affecting dynamic behavior of specimens. Thefailure patterns and shear force-displacement hysteretic characters were analyzed. The limitvalues of the axial load ratio and minimum stirrup reinforcement ratios of columns are putforward to satisfy definite ductility requirement. That limit values of the axial load ratiodecrease 0.15 than C60 columns of current speciation JGJ 138—2001; however, the minimumstirrup reinforcement ratios increase 0.4% by applying HRB400 reinforcing steel. Accordingto the low limit values of experimental results, the suggested formula for calculating shearstrength of steel SHSC columns is put forward. But the formula of current code GB50010—2002 is not enough safe.(4) The main objective was to study steel fiber and high-modulus PVA fiber effect toimprove the seismic performance of super-high-strength concrete columns, which subjectedto high axial load ratio (axial load ratio exceeds the limited value). The influence of differentfiber volume ratio to failure patterns and hysteretic characters was analyzed. According to theexperimental results, the fiber volume ratio to satisfy certain requirement of ductility is putforward, and the suggested formula for calculating shear strength of steel fiber, PVA fiberSHSC composite columns is put forward.(5) The main objective was to study steel fiber and high-modulus PVA fiber effect toimprove the seismic performance of steel reinforced super-high-strength concrete columns,which subjected to high axial load ratio (axial load ratio exceeds the limited value). Theinfluence of different fiber volume ratio to failure patterns and hysteretic characters ductilitywas analyzed, According to the experimental results, the fiber volume ratio to satisfy certainrequirement of ductility is put forward, and the suggested formula for calculating shearstrength of steel reinforced steel fiber, PVA fiber SHSC composite columns is put forward.
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