Abstract: Two interior columns on the second floor of an office buildings podium need to be removed due to functional change of the building.The amplitude of load-transition on foundation and variation of internal forces in members of the structure were calculated based on the updated load transferring path.The influence of the two removed columns on lateral stiffness and seismic performance of the structure was analyzed as well.To meet the architectural use of space and ensure convenience for construction,an integrated strengthening technology was proposed including increase of columns section,application of pre-stressed struts,bonding of external FRP plates,addition of steel bars and so on.Each method is proposed to strengthen or retrofit a specific type of members,which can provide a reference for similar structural strengthening.