Retrofit hypotheses of a pre-normative steel school building by fluid viscous damper-based technologies

Two advanced seismic protection technologies, and relevant hypotheses of application to the retrofit of an Italian pre-normative steel school building, are examined in this paper. The two technologies consist in a dissipative bracing system, and a damped cable system, both incorporating pressurized fluid viscous dampers as protecting devices. The essential characteristics and performance of the dampers and the two systems, along with their analytical/computational modelling criteria, are recalled in the first part of this paper. The dimensions, layouts and locations selected for the constituting elements of the two rehabilitation solutions are then discussed. A synthesis of the nonlinear dynamic analyses and performance-based evaluations carried out on the case study building in original and protected conditions is finally proposed

Non-linear dynamic design procedure of FV spring-dampers for base isolation - Frame building applications

The non-linear dynamic design procedure of fluid viscous spring-dampers proposed in the accompanying paper is applied to two selected case studies, represented by a reinforced concrete and a steel five-storey frame building with identical global dimensions. The fundamental vibration periods of the two structures in fixed-base conditions, equal to 0.58 s and 1.08 s, respectively, fall within the range of technical interest for use of base isolation. The reliability of the analytical relationship by which the damping coefficient is estimated in the preliminary design phase is further verified by comparing its predictions with the loss factor values calculated from the results of numerical integration of the equations of motion. The final verification phase of the procedure is then developed with regard to a double design performance objective, for which immediate occupancy and life safety levels are targeted under the \u201cbasic design\u201d and \u201cmaximum considered\u201d earthquakes, respectively

Analysis, design, and construction of a base-isolated multiple building structure

The analysis and design of a multiple residential building, seismically protected by a base isolation system incorporating double friction pendulum sliders as protective devices, are presented in the paper. The building, situated in the suburban area of Florence, is composed of four independent reinforced concrete framed structures, mutually separated by three thermal expansion joints. The plan is L-shaped, with dimensions of about 75 m in the longitudinal direction and about 30 m along the longest side of the transversal direction. These characteristics identify the structure as the largest example of a base-isolated “artificial ground” ever built in Italy. The base isolation solution guarantees lower costs, a much greater performance, and a finer architectural look, as compared to a conventional fixed-base antiseismic design. The characteristics of the building and the isolators, the mechanical properties and the experimental characterization campaign and preliminary sizing carried out on the latter, and the nonlinear time-history design and performance assessment analyses developed on the base isolated building are reported in this paper, along with details about the installation of the isolators and the plants and highlights of the construction works

Analysis, testing, design and construction of a base isolated/supplementally damped building

The first actual application to a demonstrative strategic building of a special base isolation/supplemental damping system, where fluid viscous spring-dampers are coupled to steel-Teflon sliders, is presented in this paper. The results of a testing campaign aimed at assessing the interference of the dissipative actions of the two component devices, as a final step of the research studies previously developed by the authors on this technology, are summed up. The design and performance evaluation analyses carried out on the building are then discussed. Highlights of the construction works and technical installation details are finally illustrated

Structural and historical assessment of a modern heritage masterpiece: "Palazzo del Lavoro" in Turin

A structural and historical assessment study on "Palazzo del Lavoro", a modern heritage building in Turin, designed by Pier Luigi Nervi in 1959, was carried out within a National Research Project focused on the correlations between the leading engineering and architectural activities in Italy during the 1950s and 1960s. Based on the original design documentation collected through records research, a complete finite element model of the building was generated, along with detailed models of its main structural members, represented by monumental reinforced concrete columns, a mushroom-type steel roof, and reinforced concrete ribbed gallery slabs. The results of the linear and non-linear analyses developed by these models, aimed at fully understanding the original design concept of the various members, as well as at evaluating their current static and seismic safety conditions, are summarized in the paper. Retrofit hypotheses are also proposed for the steel roof beams and the cantilever elements of the gallery floors, which did not meet some of the structural requirements. \ua9 2011 WIT Press