Advanced Seismic Retrofit of a Mixed R/C-Steel Structure

Abstract

A study concerning the performance assessment and enhanced retrofit of public buildings originally designed without any anti-seismic provisions is presented herein. A representative structure belonging to this class was demonstratively examined, i.e., a school built in Italy in the early 1970s, before a coordinate national Seismic Standard was issued. The building is characterized by a mixed reinforced concrete (ground storey)–steel (first and second storey) frame skeleton. An extensive on-site experimental investigation was developed in the first step of the study, which helped identify the mechanical characteristics of the constituting materials, and re-draw the main structural details. Based on these data, and relevant updates of the finite element model of the structure, the seismic assessment analyses carried out in current conditions highlighted several performance deficiencies, in both the reinforced concrete and steel members. An advanced seismic retrofit hypothesis of the building was then designed, consisting of the installation of a set of dissipative braces incorporating fluid viscous dampers as protective devices. This solution makes it possible to attain an elastic structural response up to the maximum considered normative earthquake level, while at the same time causing more limited architectural intrusion and lower costs as compared to conventional rehabilitation strategies.

Structural Monitoring of Underground Structures in Multi-Layer Media by Dynamic Methods

“…The geophysical structure of the Earth’s surface makes it possible to formulate the problems of the dynamics of buildings and structures lying on layered media under seismic influences. The dynamic behavior of buildings and structural elements under seismic influences are considered in the works of Terenzi et al [ 2 ], Di Lorenzo et al [ 3 ], and Sabino et al [ 4 ].…”

Response of an Existing Two-Storey RC Frame Designed for Gravity Loads: In Situ Pushover Tests and Numerical Analyses

“…In the last years, a number of on-site characterization tests allowed for models to be defined to study the effects of seismic motion on real existing buildings, designed to sustain vertical loads only. The poor performances of the large part of the existing construction portfolio built before the development of consolidated seismic codes and standards, as underlined by the last seismic events, is surely one of the main motivations for these researches (e.g., [1][2][3]).…”