This publication on seismic strengthening of existing buildings is one of a series that FEMA is sponsoring to encourage local decision makers, design professionals, and other interested groups to undertake a program of mitigating the risks posed by existing hazardous buildings in the event of an earthquake. Publications in this series are being prepared under the National Earthquake Hazards Reduction Program (NEHRP) and examine both the engineering/architectural aspects and societal impacts of seismic rehabilitation. FEMA's existing buildings activities are structured to result in a coherent, cohesive, carefully selected and planned reinforcing set of documents designed for national applicability. The resulting publications (descriptive reports, handbooks, and supporting documentation) provide guidance primarily to local elected and appointed officials and design professionals on how to deal not only with earthquake engineering problems but also with the public policy issues and societal dislocations associated with major seismic events. This handbook of techniques for solving a variety of seismic rehabilitation problems and its companion publication on the seismic evaluation of existing buildings reflect basic input provided by two organizations recognized for their retrofit evaluation and design experience as well as the results of a consensus development activity carried out by the Building Seismic Safety Council (BSSC). The preliminary version of this document, the NEHRP Handbook of Techniques for the Seismic Rehabilitation of Existing Buildings, was developed for FEMA by URS/John A. Blume and Associates, Engineers (URS/Blume). A companion volume, the NEHRP Handbook for the Seismic Evaluation of Existing Buildings, for which a preliminary version was developed for FEMA by the Applied Technology Council (ATC), provides a method for evaluating existing buildings to identify those that are likely to be seismically hazardous. The BSSC project, initiated at the request of FEMA in October 1988, has focused on identification and resolution of technical issues in and appropriate revision of the two handbooks by a 22-member Retrofit of Existing Buildings (REB) Committee composed of individuals possessing expertise in the various subjects needed to address seismic rehabilitation.