PREFACE The present code is the revised version of the former "Code for seismic design of build- ings"GBJ 11-89.The revision is undertaken by China Academy of Building Research (CABR)together with other institutions related to design,reconnaissance,research,and universities in accordance with the Document JB [1997]No.108 issued by the Ministry of Construction. During the process of revision,the editorial team carried out studies on specific topics and some laboratory tests concerned.Experiences and lessons,learned from damages in- duced by strong earthquake having occurred in recent years home and abroad,are summa rized,achievements of research in earthquake engineering are involved,the economic condi- tion and construction practices in China are taken into account,comments from all aspects of design,reconnaissance,research,education and municipal authorities are widely collected nation wide.Through a multi-round discussion,revision,substantiation,and with pilot de- signs as well,the final version has been completed and reviewed by an expert panel The newly updated version consists of 13 chapters and 11 appendixes.The major con- tents of the revision can be clarified by follows:the seismic fortification classification for buildings has been adjusted;the seismic design is required to be based on the design basic ac- celeration of the ground motion:the near-field and far-field earthquakes employed by the previous code have been replaced by the design earthquake groups;provisions related to the site classification,liquefaction identification,seismic influence coefficient and torsion effect calculation have been modified;requirements for the conception design of irregular building structures,the seismic analysis of structures,the limit of inter-story seismic shear force and deformation have been added;the seismic measures of masonry and concrete structures,and masonry buildings with bottom R.C.frames have been improved;more contents related to active fracture,pile foundation,R.C.tube structure,steel structure,reinforced hollow block masonry structure,and non-structural components,as well as the provisions for bas isolation and energy dissipation have been involved.In the meantime,the new code has ab- rogated some provisions dealing with inner-frame house and medium-sized block masonry structure,chimney and water tower,etc. The new code could be partly modified in the future.The relevant information and de- tails ofwill be published on the mg tion" Clauses marked with boldface type in this code are compulsory provisions and must be enforced strictly. The Institute of Earthquake Engineering of CABR is responsible for the interpretation of this code.Hopefully,in the process of its enforcement,all institutions may sum up and