SEISMIC DESIGN AND RETROFIT MANUAL FOR HIGHWAY BRIDGES. FINAL REPORT

This manual is a guide to the seismic design of bridges. It presents the basic principles of seismology, structural dynamics and structural form as they relate to highway bridge structures. Seismic design concepts are presented which highlight the importance of simplicity, symmetry and integrity for bridges. Examples of acceptable structural form and form to be avoided are included. Past earthquake damage is reviewed and a philosophy for seismic bridge design is presented. Analysis methods for calculating design forces and displacement are developed, and relevant computer software is discussed. Numerical examples are used to illustrate design concepts and the recommended design procedures. A methodology for seismic retrofitting is also presented, which includes discussion of bridge evaluation procedures, capacity/demand ratios and design concepts for strengthening and upgrading existing vulnerable bridges. The philosophy and procedures presented in this manual are consistent with those recently developed by the Applied Technology Council (ATC) with funding from the Federal Highway Administration (FHWA) and now adopted by the American Association of State Highway and Transportation Officials (AASHTO). This manual synthesizes the criteria and recommendations of the above agencies (ATC, FHWA, and AASHTO) and incorporates recent work by the California Department of Transportation and the Earth Technology Corporation of California.