Experiment Study On The Seismic Behavior Of Rc Short Columns Strengthened With Prestressed Steel Wires

As new strengthening technology, prestressed steel wires (PSW)strengthening can effectively enhance the seismic performance of RC shortcolumns, and it exhibits wide prospect in the field of structural rehabilitation. Inorder to study the engreening application of PSW technology, following studieswere carried out:1)Experimental Study on the Seismic Behavior of ConcreteShort Columns Strengthened with PSW;2)The mechanism of the concrete columnStrengthened with PSW has been studied in this paper,and formulas to calculatethe ultimate shear bearing capacity of RC columns retrofitted by PSW wereproposed.The seismic experiments of Thirteen RC short columns strengthened withPSW under low frequency cyclic loading are carried out, failure mode,hysteresiscurves, skeleton curves, ductility, stiffness degradation,energy dissipation anddamage evolution are analyzed, the effects of configuration index ofPSW,prestressing level of PSW and axial compression ratio on the seismicbehavior are studied.The results show that the seismic performance of the shortcolumns retrofitted in the method of PSW could be effectively enhanced. Theductility index and the energy dissipation capacity of the retrofitted specimensincrease with the configuration index and/or the prestressing level of steel wire.The biggest displacement ductility factor and accumulated energy dissipation ofthe columns strengthened with PSW are1.87times and6.78times higherrespectively than that of the un strengthened column. The seismic performance ofthe retrofitted columns can be improved significantly by increasing the theconfiguration index and/or the prestressing level of PSW.If the configurationindex of PSW is bigger than0.119,the prestressing level reaches0.40,the seismicperformance of the retrofitted specimens can be improved effectively when theaxial load ratio is lower than0.3.For retrofitted specimens that axial load ratio isbigger than0.8, the configuration index of PSW is recommended no less than0.237.The strain development of PSW and stirrup are analyzed,The mechanism ofthe concrete column has been studied in this paper. Based the test results, tworeasonable shear capability design formula is presented. the calculated results are safety and show good agreement with the tested one sand can be referenced inengineering practice.