SEISMIC APPRAISAL AND STRENGTHENING DESIGN OF A STOREY-ADDING-FRAME STRUCTURE

Because of the change of functions,a six-story frame industrial workshop was reconstructed to a nine-story frame structure building used as hotel.The field inspection and seismic appraisal of the original building were carried out,the results could meet various requirements of the present Chinese code.According to the problems when storey adding directly,for instance,the ratios of the axial compression to axial compressive strength of some frame columns would be beyond the limit,the longitudinal reinforcement ratios of frame beams would be less than the service level,and some stories drift would be beyond the limit of seismic design code,strengthening designs,including pressure grouting in treatment for foundation like enlarging cross-section of columns and beams,and adding short pier shear wall to increase the lateral displacement stiffness of structure were provided.Based on the analysis of the structure after strengthening,the effect of the seismic strengthening design was excellent.