A Comprehensive Approach for the Seismic Vulnerability of a Building of Public Utility

Abstract

The purpose of research. The paper presents a complex approach performed to identify the vibration natural periods of a building of general interest, in the form of H, with basement, ground floor and 7 levels, built in 1968. Thus, qualitative and quantitative analyzes, topometric measurements, non-destructive tests, vibration recordings from microseisms, in order to establish the general technical condition, the degree of geometric conformation, the determination of dynamic characteristics, as well as static, modal modeling etc. for the validation of those obtained results were made. Finally, proposing several consolidation solutions, because the building is located in Bucharest where the peak ground acceleration (PGA) is 0.3g according to the Seismic design code and a further increase to a mean return period of 475 years for PGAis taken into consideration. At this moment, this building is in the process of consolidation and rehabilitation and will be included in the national permanent vibrations monitoring program. Principal results: eccentricities and irregularities from non-structural components, relative horizontal displacements, sclerometric and ultrasonic recordings, spatial structure displacements in the three main directions NS, EV and vertical Z, velocities, accelerations, frequencies and periods, structural damping factors, basic shear force etc. Major conclusions. It is important to obtain correct information regarding the behaviour of a structural system, the contribution of each presented technical approaches is consistent, using the advantages of non-destructive methods, ambient vibration monitoring and modal analysis. Reducing the seismic risk of buildings in Romania is a complex action nowadays, of national interest, and in 2020, a national strategy on seismic risk reduction will be finalized (with legislative, normative, investment reforms etc.).