Search results for "Seismic retrofit"
showing 10 items of 10 documents
A practical approach for the strength evaluation of RC columns reinforced with RC jackets
2015
Abstract Reinforced concrete (RC) jacketing is nowadays one of the most common techniques adopted for seismic retrofitting of existing RC columns. It is used to increase load-carrying capacity and ductility of weak existing members by means of a simple and cheap method. The structural efficiency is related to two main effects: – the enlargement of the transverse cross section; – the confinement action provided by the external jacket to the inner core. Several theoretical and experimental studies were addressed in the past to investigate on how it is possible to calculate the strength enhancement due to these effects and to highlight the main key parameters influencing the structural behavio…
Upwards - Vertical extensions of masonry built heritage for sustainable and antifragile urban densification
2021
Abstract Urban densification represents one of the biggest universal challenges of contemporary cities: the increase of urban population requires new spaces to accommodate the growing demand for housing, working and tertiary activities. However, the land available for new constructions in highly urbanized areas is very limited. In this framework, the vertical extension of existing buildings is the most sustainable strategy and fascinating. Masonry structures , constituting a major part of the built stock in the historical city centres of several European countries, are particularly suitable for vertical addition of extra-floors, since they generally exhibit an adequate overstrength for bear…
Coupling of Structural Additions for the Mitigation of Seismic Response in Existing Buildings
2023
In the present paper, additions in structural steelwork are utilized for giving new life to old buildings in regions characterized by medium/high seismic hazard. Two models are here proposed, i.e.: vertical addition for masonry buildings and lateral addition for r.c. buildings. For the model of vertical addition, the connection between the masonry and steel structures is realized by means of an Intermediate Isolation System (IIS). For the model of lateral addition, an exoskeleton (EXO) is connected to the existing building by means of rigid or flexible and dissipative link. Two buildings, representative of the heterogeneous Italian building stock, are selected as case studies. Parametric an…
Intermediate Isolation System with Nonlinear Lower Structure and Isolation System
2023
This paper reports a study on the Intermediate Isolation System (IIS) applied to existing buildings. This kind of application is particularly suitable when a vertical addition is planned for buildings in seismic zones; in such a case, an isolation system can be placed at the base of the extension to prevent the increase, or, better, to reduce the seismic demand on the existing structure. In previous works, parametric response spectrum analyses have been carried out on lumped mass models by varying the period of the isolation system. As a result, a sort of IIS design spectrum has been derived and used for selecting design solutions for the vertical extension that minimize the overall seismic…
Optimal design algorithm for seismic retrofitting of RC columns with steel jacketing technique
2020
Abstract Steel jacketing (SJ) of beams and columns is widely employed as retrofitting technique to provide additional deformation and strength capacity to existing reinforced concrete (RC) frame structures. The latter are many times designed without considering seismic loads, or present inadequate seismic detailing. The use of SJ is generally associated with non-negligible costs depending on the amount of structural work and non-structural manufacturing and materials. Moreover, this kind of intervention results in noticeable downtime for the building. This paper presents a new optimization framework which is aimed at obtaining minimization of retrofitting costs by optimizing the position an…
NONSTRUCTURAL SEISMIC PREVENTION AND REHABILITATION
2010
Il progetto di cooperazione internazionale finanziato nell’ambito del programma CoRI 2005/2006 dell’Ateneo di Palermo, ha visto coinvolte l’Università di Palermo e l’Università di Berkeley – USA, nella persona della Prof. Mary C. Comerio (Chair Department of Architecture). La prima fase del progetto è stata volta alla conoscenza dell’esperienza USA nella gestione degli edifici scolastici per potere riversare nella realtà italiana significativi apporti. La seconda fase del progetto ha previsto occasioni di confronto diretto con duplici finalità, sia di ricerca che di formazione didattica. Tra le varie attività previste nell’ambito di questa occasione, è stato organizzato un workshop in cui s…
The Effect of Nonlinear Response of the Primary System in Nonconventional TMDs
2023
Tuned Mass Dampers (TMD) have been widely used in the passive vibration control of engineering structures, both under wind and seismic loads. Under wind loads, a proper frequency tuning ensures a significant response reduction of the primary structure. While under wind loads the structure is likely to remain in the elastic range of behaviour, when large earthquakes occur it can experience inelastic deformations and damage, with a consequent de-tuning effect. In this paper, nonconventional TMDs with large mass ratios, realized through Interstory Isolation Systems (IIS), are considered and the influence of the inelastic behaviour of the primary system on the overall structure response is anal…
Effectiveness of isolated vertical extension of masonry buildings as nonconventional TMD
2023
In this paper, the strategy of Intermediate Isolation System (IIS) is proposed for the vertical extension of an aggregate of masonry buildings located in Pozzuoli, south Italy. The effectiveness of IIS working as a nonconventional Tuned Mass Damper (TMD) for the existing construction is assessed in terms of reduction of seismic demand and damage in the masonry structure undergoing inelastic deformation under seismic input. For this aim, a general step-by-step procedure is first defined and then applied to the case study building. In particular, the characterization of dynamic behaviour and seismic capacity of the building aggregate is first addressed through modal and push over analyses. El…
Genetic Optimization for the design of seismic retrofitting of plane RC frames with Buckling Restrained Braces (BRBs)
2021
The increasing development of computational power in modern digital devices has spread the use of structural optimization in design applications of different fields of engineering problems. This approach exposes engineers to challenging design procedures aimed to optimize all variables to satisfy the imposed requirements, finding the “optimal” solution. Despite this wide use, the application of optimization algorithms for the design of seismic retrofitting strategies becomes tougher, due to the difficulties in finding a mathematical expression which includes and combines all the key variables (i.e., cost, safety, sustainability, design) and the nonlinearity of the analysis. In this paper, t…
Intermediate Isolation System for the seismic retrofit of existing masonry buildings
2022
This paper deals with the potentials of Intermediate Isolation Systems (IIS) for retrofitting masonry buildings by means of a vertical extension, isolated at its base, and realized on the rooftop of the existing structure. By carefully defining the dynamic properties of the superstructure and isolation system, in previous papers the authors have demonstrated that this passive technique is able to reduce a priori the seismic demand on the existing building. For this reason, the non-linear behavior has been only assumed for the isolation system, with the masonry structure in the elastic field. This result has been validated by carrying out spectrum-compatible time history analyses on the 3D F…