Seismic Retrofit of an Existing RC Building With Isolation Devices Applied at Base

Abstract

Nowadays, seismic retrofit through isolation strategy represents a consolidated technique of protection against design earthquakes. This technique is also applied on existing structures extensively, due to the fact that it usually does not require any interruption of the building use and occupants evacuation. If applicable, it rapidly allows the seismically retrofitting of a building installed with seismic devices with low horizontal stiffness between the structure and the foundation decoupling, in fact, this allows the motion of the superstructure from the ground one. In this paper an application on an existing RC building of the seismic isolation is presented. The chosen building was built in the '90s only for vertical loads and realized without any detailing rule for structural ductility. The seismic retrofitting requirement stems from the fact that only recently, after the National seismic hazard maps update in 2003, the considered area has been upgraded to a medium-low seismic intensity zone, while at construction time no seismic classification was in existence by law. The case study peculiarity is that the seismic retrofitting has required an addition to seismic devices at the base, with related interventions such as the application of a bracing system consisting of two elastic steel frames. This intervention is required for stiffening the superstructure and, therefore, minimizing the higher vibration modes effects. The paper presents the main results obtained with a FEM model, implemented for simulating the initial and the design state when the interventions are considered. Finally, some results of non-linear dynamic time-history analyses are illustrated and commented for verifying superstructure elements and seismic devices.

Use of OR in earthquake operations management: A review of the literature and roadmap for future research

“…Here, various techniques used in the field of seismology, including machine learning, might prove particularly useful in estimating damage levels [58,66] and human losses [67] based on key variables like structure type, construction quality, built area, and occupancy level. Subsequent application of simulation to assess key uncertainties combined with earthquake engineering to specify feasible fortification/retrofit alternatives [260,261] could form the basis for developing more holistic and realistic mathematical programing or heuristic methods to efficiently allocate limited protection resources. Similar to protection planning type studies, greater use of forecasting methods from the seismology (e.g., for estimating the intensity and frequency of quakes) would significantly enhance the rigor of relief pre-positioning and resource planning models.…”

A Performance Evaluation of Seismic Retrofit of Existing Greece Building

“…The study underscores the importance of performance-based design, using computer software modeling and analyses to enhance seismic resistance and prevent structural collapse under design loads. D'Amato [7] investigated the seismic retro tting of an existing RC building from the '90s, initially designed only for vertical loads, which was achieved through the application of seismic isolation. This involved adding seismic devices at the base, including a bracing system with two elastic steel frames to stiffen the superstructure and minimize higher vibration modes' effects.…”

An asymmetric quasi-zero stiffness vibration isolator with long stroke and large bearing capacity

“…Installment of vibration isolators between vibration source and isolated objects is a common way for vibration isolation and has been widely used to maintain the reliable operation of precision instruments [1,2], improve the comfort of vehicle ride [3][4][5], assist space launch or on-orbit operation [6], ensure the safety of building constructions or bridge structures [7,8] and so on. With the development of vibration isolation technology, diverse vibration isolators have emerged to cope with the ever increasing demands for high vibration isolation performance, especially the demands for low frequency and even ultra-low frequency vibration isolation [9,10].…”