Analysis of Code Procedures for Seismic Assessment of Existing Buildings: Italian Seismic Code, EC8, ATC-40, FEMA356, FEMA440

摘要

It is widely recognized that ground shaking may induce unacceptable levels of damage in existing buildings located in seismic regions. This vulnerability has been attributed to several reasons, such as insufficient strength and stiffness, poor detailing, irregularities in plan and elevation, domination of brittle failure modes over ductile ones, etc. On account of that, seismic assessment of existing buildings is adopted as a problem which needs specific treatment in building codes. The present study analyzes five codes for assessment of existing buildings: the Italian seismic code, EC8, FEMA356, ATC-40 and FEMA440. The analysis of each code is performed within a common theoretical frame. The code assumptions and simplifications are pointed out together with their possible inconsistencies and weaknesses. Comparisons between the different procedures are performed as well. The most important outcomes stress insufficiencies in the analysis procedures as well as in the criteria for choice of model dimension and analysis type, consideration of dynamic P-Δ effects, in non-linear modeling, shear resistance evaluation, and application of force-based procedures.