The existing frame columns could be retrofitted by the method of adding new retrofit concrete section on one lateral column side.The seismic capacity of the structure could be increased and the influence caused by the retrofit construction process to the building interior space could also be reduced by this new retrofit method.Five reninforced concrete columns retrofitted with asymmetric single lateral side concrete section were designed and tested through the low cycle reversed loading test.The new added concrete section adopted for specimens is normal concrete and the bonded prestressed concrete

the new section was connected with the original column through the anchorage steel bars.Based on the experimental study

the hysteretic curves

skeleton curves

strength degradation

second order moment effect and the steel bars strain were analyzed

some suggestions for seismic design of the retrofit column were also proposed.The test results show that the seismic performance of the retrofitted columns has been significantly improved

the difference of the initial stress between the new added strengthening section and the existing column section could be reduced and the second order moment effects could also be decreased due to the application of the prestressing force.Moreover

the finite element analysis model of the retrofit column specimens was set up through the software of ABAQUS and the skeleton curves were calctulated.The finite element method analysis results show good agreement with the test results.