Rosario Gigliotti

• Sapienza University of Rome

The life-cycle management objective is to predict construction future, by controlling the factors that may threaten its performance. In doing so, being this prediction affected by uncertainties, it is necessary a probabilistic description of all variables governing the construction behavior. In this study a new reliability-based procedure is presen...

Steel modular building is an alternative to conventional constructions with the advantages in terms of construction time, reversibility, durability, flexibility and sustainability. This type of construction is composed by modules assembled horizontally and vertically with steel connections. In this work, a steel connection between adjacent modules...

As known, seismic isolation is one of the most efficient techniques for protecting buildings from earthquake action reducing conspicuously the structural damage. By limiting the forces transmitted to the superstructure, this technique implies significant displacements in correspondence of the isolation level where seismic devices are installed that...

In this study typological fragility curves are proposed with a macro-seismic approach. To this scope, a stock of 56.338 residential masonry buildings struck by L'Aquila 2009 seismic sequence is analyzed, whose AeDES forms are archived within Da.D.O. platform, that is a web-gis database collecting the observed seismic damage data related to building...

In this paper a seismic risk analysis of masonry buildings based on damage data from the 2009 L'Aquila and 2012 Emilia earthquakes. The seismic vulnerability is described by fragili-ty curves from which economic loss curves are derived for each representative typological class of masonry buildings. The information on the buildings was collected by...

A R T I C L E I N F O Keywords: Probabilistic nonlinear static analysis-PNSA Probabilistic nonlinear dynamic analysis-PNDA Infill-frame interaction Shear failure Epistemic uncertainty Sensitivity analysis Tornado diagram A B S T R A C T The seismic response of infilled frame reinforced concrete structures is affected by different sources of aleator...

In this paper results obtained from monotonic nonlinear static analyses performed on Reinforced Concrete (RC) internal beam-column sub-assembly are shown. Bond-slip phenomenon between steel longitudinal bars and surrounding concrete is also taken into account in order to predict the numerical response under lateral actions of the RC internal beam-c...

The paper presents an overview of some common issues related to the seismic isolation technique applied to existing RC buildings. At first, the issues considered are briefly described. Then, solutions on how to solve them are illustrated with reference to case studies on which the seismic isolation is applied. The interventions are to date only des...

In this paper results obtained from monotonic nonlinear static analyses performed on Reinforced Concrete (RC) columns are shown. Bond-slip phenomenon between steel longitudinal bars and surrounding concrete is also taken into account in order to predict the numerical response under lateral actions of the RC columns investigated. The study is addre...

Recently, there is an increasing interest to develop modular multi-storey structures that can be adapted to any use like hospitals, schools, housing, etc, characterized by versatility and speed of use in several conditions. Modular buildings may form complete building blocks with structural systems composed by several elements, such as steel frames...

Earthquakes in the recent past continue to provide more and more information on the seismic behavior of existing buildings and on the related economic losses. For the reason it is interesting to compare the damage of buildings stocks archived after earthquakes survey activities. In this paper a study of the damage occurred on masonry buildings aft...

Modular buildings are a new type of structural system composed by prefabricated modular units and assembled on site through inter-modular connections. These structures can form complete building blocks with suspended ceilings and installations, including electrical and water systems. These modular solutions can be adapted to any use like hospitals,...

As known, the frictional behavior of steel-PTFE interfaces under seismic excitation is mainly influenced by a combination of sliding velocity, contact pressure and surface temperature. However, the calibration of specified relationships among these factors and the friction coefficient is independently conducted from each other starting from experim...

In this study some results of seismic risk analysis conducted on an Italian existing masonry buildings stock are shown. In particular, typological vulnerability and fragility curves are presented by analyzing the AeDES forms available in Da.D.O. web-gis database, collecting the damage data due to L’Aquila 2009 earthquake. The obtained results clear...

A buildings stock of 12,016 Reinforced Concrete (RC) buildings is investigated to propose vulnerability, fragility, and loss curves, as well as an Expected Annual Loss (EAL) assessment. The buildings data are collected within Da.D.O. database, considering the observed damage due to L’Aquila earthquake (2009). The adopted methodology allows us to ad...

p>Elastomeric bearings used as seismic isolation devices are key elements in the protection of constructions against earthquakes. They enable structures to exhibit very high performances when subject to extreme events, preventing damage both to structural and non-structural components. Their characteristics, however, are prone to change with time d...

This paper illustrates an original and simple method to predict earthquake-induced deformations of geotechnical systems. The method is an extension of static non-linear analysis, and is conceived to predict the behaviour of geotechnical systems, like supported and unsupported excavations, that during the seismic motion accumulate displacements in a...

In this study a seismic risk analysis of masonry buildings based on damage data of L'Aquila 2009 earthquake is presented. Typological loss curves and Expected Annualized Losses (EAL) values are presented, starting from the data collected into AeDES forms available in the Da.D.O. database. A completion is proposed for improving the sample statistica...

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 se...

Control and inspection of the conditions of elastomeric bearings used for seismic isolation purpose is a fundamental activity in ensuring and preserving the performance of a structure. The methods currently used, such as visual inspections, Operational Modal Analysis (OMA), release tests, very often present strong limitations due to their qualitati...

The assessment of maximum displacement demand is a crucial point in the design of seismic isolating systems, in particular when the non linear behaviour of devices is modeled through visco-elastic equivalent schemes, as common in the design practice. Several phenomena influence the maximum demand assessment, among which the torsional and earthquake...

This paper illustrates the extension to the rectangular section of an analytical model for confined concrete proposed for square sections confined by steel stirrups and/or FRP jackets. The confined concrete model is developed starting from the elasticity theory and under the key assumption that the confinement acts under the plane-strain conditions...

An overview of some simplified methods for assessing the seismic performance of ancient churches is presented in this paper. In particular, the simplified methods proposed by the current Italian directive containing the guidelines for assessment and reduction of cultural heritage seismic risk are analyzed. These methods have an increasing precision...

The seismic risk assessment of the historical and architectural heritage is, nowadays, a very relevant topic due the potential human and economic losses involved in case of global or partial collapse. In order to preserve the inestimable value of such heritage, the prevention and mitigation of the seismic risk is needed and it cannot be postponed....

In this paper a multiperformance optimization procedure to design dissipative bracing systems controlling the structural performance while minimizing the intervention cost is proposed. The procedure allows dimensional and topological optimization of bracing, considering inelastic behaviour of braced structures through properly developed visco-elast...

The protection of cultural heritage against earthquake induced actions is one of the mainchallenges the earthquake engineering science and practice are facing. This article presentsa seismic assessment study on one of the most ancient colonial buildings present in Peru, theCathedral of Lima, focusing on its towers. A historical review highlighted h...

This paper focuses on the seismic evaluation of the Bell Towers of Lima’s Cathedral. The church, which dates back to 1535, has been modified and reconstructed several times over the centuries, changing its structural assembly in terms of lightening and strengthening. Focusing on the massive 45 m tall towers, linear kinematic analyses have been perf...

A comparative seismic loss analysis is presented for a non-ductile infilled reinforced concrete building evaluating the influence on direct economic losses of different parameters characterizing a building performance model. Propagation of uncertainties to seismic repair cost estimate is investigated in terms of effect of input intensity measures,...

A graphical dynamic model is presented to predict the directional earthquake response of two-ways plan-asymmetric buildings. The theoretical principles inherent to torsional dynamics and vibrations are investigated and the dynamic directional response is rationally explained based on modal rotational kinematics about modal torsional pivots. Seismic...

The seismic response of older R/C frames can be particularly sensitive to interaction with masonry infills, poor section detailing and smooth reinforcing bars. These aspects are quite often neglected in design and assessment both with linear and nonlinear models due to the modelling complexity and inherent increase in computational effort. This wor...

Mean annual financial losses due to seismic events in Italy are about 2–3 billion euro. For this reason, in recent years increasing attention has been placed on strategies to reduce the seismic risk of the national building stock. In this work, a comparative seismic loss analysis of an infilled R/C building is performed using the FEMA P-58 probabil...

This paper presents a performance-based earthquake assessment of an industrial structure, aiming at identifying suitable techniques to select and scale natural ground motions for 3D analysis and improve the structural response prediction of complex structures. To this end, an industrial structure characterized by the presence of large masses placed...

The paper describes a modified cyclic bar model including bond-slip phenomena between steel reinforcing bars and surrounding concrete. The model is focused on plain bar and is useful, for its simplicity, for the seismic analyses of RC structures with plain bars and insufficient constructive details, such as in the case of '60s -'70s Mediterranean b...

The maximum seismic response of torsionally coupled plan asymmetric structures can be rationally visualized and computed through a Mohr Circle Response Spectrum Analysis (MCRSA). This is done combining the graphic modal properties of the torsional dynamic equations of motion with the structural earthquake demand in terms of a displacement spectrum...

This paper documents and analyzes the seismic behavior of unreinforced masonry (URM) buildings that were damaged by the 2015 Gorkha earthquake in Nepal, and reports on the performance of palaces, giving an overview on the failures suffered by significant examples of these monumental buildings. Field reconnaissance was completed through both rapid,...

This paper illustrates numerical simulations and comparisons with experimental results of existing RC beam-column sub-assemblages reinforced with smooth bars. The specimens reproduce parts of concrete structures designed only for vertical loads without any reinforcing detail rule (such as inadequate bars lap splice, absence of hoops within the join...

In this paper, an analytical model of confined concrete proposed for square sections is extended to the case of rectangular ones. The new and generalized formulation, based on the elasticity theory, is developed under the key assumption that the confinement arises in plane-strain conditions. The proposed model provides, through the analogy among th...

This paper aims to propose numerical models for seismic assessment of old existing RC beam-column sub-assemblages. In particular, two modeling approaches are described: for internal (usually named “C joints”) and for external (named “T joints”) beam-column sub-assemblages, both designed only for vertical loads without reinforcing details rules (suc...

A new constitutive model for the representation of the seismic behaviour of steel bars including hardening phenomena is presented. The model takes into account relative slip between bars and concrete, necessary for the estimation of the structural behaviour of r.c. elements and of the level of strain induced by earthquakes on bars. The present work...

Mean annual financial losses due to seismic events in Italy are about 2-3 billion euro. For this reason, in recent years increasing attention has been placed on strategies to reduce the seismic risk of the national building stock. In this work, a comparative seismic loss analysis of an infilled R/C building is performed using the probabilistic fram...

A Mohr Circle-based method for Graphic Response Spectrum Analysis of one-way asymmetric torsionally coupled systems is presented. The approach uses the properties of the Mohr Circle of the torsional dynamic equations of motion and the earthquake input expressed in terms of displacement spectrum as a function of the modal eigenvalues SD(ω2). A synth...

This paper reports on the damage reconnaissance activities carried out by the authors in Nepal after the seismic event that shook the district of Gorkha on April 25, 2005 and the main aftershock that hit the district of Dolakha on May 12. The first part provides information on the earthquakes' characteristics, as well as on the large scale effects...

A Graphical Dynamic model is derived to describe the directional earthquake response of two-ways plan-asymmetric systems, which retains the insightful educational evidence of traditional graphical static methods and the accuracy of computational methods of analysis. The dynamic directional response is expressed in terms of modal rotational kinemat-...

Masonry infilled R/C buildings present a number of complexities inherent to in-plan eccentricities and asymmetric layout of infills. Their dynamic earthquake response cannot generally be characterized in terms of principal directions of deflection as for plan-regular structures. The response is then complicated by nonlinear frame-infill interaction...

The Emilia, May-July 2012, earthquake has dramatically highlighted the only the hazards facing the people in insufficiently secured workplaces, but also the socio-economic consequences of interruption of production activities. After the event, in order to guarantee suitable safety levels, the Italian government asked for a generalized seismic retro...

Modern design standards for reinforced concrete (r.c.) buildings allow the achievement of ductile structures, able to globally dissipate seismic energy through the development of plastic deformations located in the dissipative regions (i.e. plastic hinges). The hysteretic capacity of r.c. structures is related to the ability of reinforcing steel ba...

The Emilia, May–July 2012, earthquake hit a highly industrialized area, where some tens thousands industrial buldings, mainly single storey precast structures, are located. Due to the likelihood of strong after shocks and the high vulnerability of these structures, the authorities first asked for a generalized seismic retrofit after the strong shak...

The seismic performance of older infilled frame reinforced concrete structures is influenced by the interaction of different components and mechanisms and is highly sensitive to several modelling parameters. A probabilistic response sensitivity analysis is performed on a case study consisting of an infilled frame structure incorporating state-of th...

In moment resisting frame structures special detailing rules are applied to critical regions of primary columns and beams to ensure adequate curvature ductility. This is necessary for dissipating earthquake energy through hysteretical behavior of critical regions where inelastic flexural excursions occur. In this paper codal detailing rules for des...

Infills can have a significant influence on the stiffness, strength, ductility, and other key modelling parameters of non-ductile R/C frames, thus resulting in very different response evaluation. They are quite often neglected in linear or nonlinear models because of the modelling complexity and increase in computational effort. To investigate the...

In this paper the implementation and validation of a modified steel bar model including bond-slip of longitudinal bars that was proposed in a companion paper is discussed. The model is developed on the key assumption of linear slip field along the steel bar with different configurations at the ends of the bar. The simplified model is capable of pre...

A numerical general-purpose confinement model implemented in an open source non-linear structural analysis program is presented. Emphasis is placed on the procedure to obtain the envelope curve of confined concrete and on the iterative procedure required to ensure stable results.The numerical model represents an useful tool to account for confineme...

A new uniaxial confined concrete material has been added in OpenSees. The material allows of performing non-linear analyses by using the confined concrete model proposed by Braga, Gigliotti and Laterza (named BGL model). The model takes into account different confining arrangements of transverse reinforcements and/or external strengthenings, such a...

This paper presents a simplified model for describing the response of a longitudinal bar embedded in concrete, taking into account the bond-slip phenomenon. The model is developed by assuming a linear bond-slip field along the bar anchorage length and provides a simplified stress-strain relationship to assign to the longitudinal reinforcement. The...

Despite the remarkable scientific advancements of earthquake engineering and seismology in many countries, seismic risk is still growing at a high rate in the world’s most vulnerable communities. Successful practices have shown that a community’s capacity to manage and reduce its seismic risk relies on capitalization on policies, on technology and...

In the present paper, developed inside the framework of the European Research project Rusteel, the behaviour of steel reinforcing bars under the combined effects of low-cycle fatigue action and corrosion phenomena is studied. The project aims at the definition of the effective ductility capacity of reinforcements, to be compared with the ductility...

The paper illustrates the results of experimental tests performed on sub-assemblages of R/C (Reinforced Concrete) existing structures, designed only for gravity loads In order to estimate failure mechanisms and ductility properties, four internal and external R/C beam-column joints were built and tested. The specimens were built by using concrete w...

In order to evaluate the capacity of RC members, the main codes allow the use of stress-strain laws that can re-produce closely the real behaviour of concrete, as opposed to parabola-rectangular or equivalent rectangular diagrams. Both sectional strength and ductility depend on the law of concrete, therefore they are influenced by the confinement o...

La modellazione delle strutture isolate in presenza di sistemi di isolamento nonlineare e l'analisi dinamica nonlineare semplificata secondo l'OPC 3274/3431 (punto 10.7.6). SOMMARIO: In contrasto con vari studi presenti in letteratura e con varie normative sull'isolamento sismico tra cui l'EC8, cui essa si ispira, la OPC 3274/3431 al punto 10.7.6 i...

La modellazione delle strutture isolate in presenza di sistemi di isolamento nonlineare e l'analisi dinamica nonlineare semplificata secondo l'OPC 3274/3431 (punto 10.7.6). SOMMARIO: In contrasto con vari studi presenti in letteratura e con varie normative sull'isolamento sismico tra cui l'EC8, cui essa si ispira, la OPC 3274/3431 al punto 10.7.6 i...

This paper presents a plain strain analytical model, based on the elasticity theory, to determine the confining pressures of transverse reinforcements on the concrete core of a reinforced concrete member. The analytical evaluation of the confining pressures was first carried out on reinforced sections with square and circular stirrups, and subseque...

The isolation systems are usually made of rubber bearings that are sometimes coupled in hybrid combination with frictional devices; this is the case of an in-site experimental campaign, performed on a base isolated apartment building in Rapolla (south of Italy). Several dropout tests at initial displacements up to 17cm allowed to obtain in-site inf...

SOMMARIO: I meccanismi di risposta di nodi trave-pilastro in c.a. sono stati studiati attraverso prove sperimentali, realizzate in modo da riprodurre la deformata degli elementi strutturali in presenza di carichi verticali ed azioni orizzontali. I nodi, realizzati in scala 1:1 ed in scala 2:3 costituiscono dei sottoassemblaggi di una struttura trid...

An application of a mixed seismic isolation system (slide bearings for isolation and steel rubber bearings to have a recentering force) is presented. Such technique has been applied to a residence building, built in Italy at Rapolla (PZ-Basilicata). The application has allowed to investigate, through a series of dynamic Snap-Back tests, the behavio...

A fiber-beam element is modified for studying the effects of bond decay by using smooth steel bars on the behavior of R/C frames designed without antiseismic provisions. In or- der to describe the phenomenon, the efficiency of the curvilinear bars anchorage is estimated by a theoretical model, which is much easy to insert in the concentrated plasti...

SOMMARIO: Il confinamento del calcestruzzo è stato affrontato su base totalmente analitica. La teoria consente di descrivere la distribuzione delle tensioni lungo le armature longitudinali, trasversali ed all'interno del nucleo confinato. Essa rispetta sia l'equilibrio delle forze che la congruenza delle deformazioni tra staffe e nucleo di calcestr...

In contrasto con vari studi presenti in letteratura e con varie normative sull'isolamento sismico tra cui l'EC8, cui essa si ispira, la OPC 3274/3431 al punto 10.7.6 introduce un metodo semplificato per l'analisi nonlineare di edifici isolati alla base, che appare del tutto incongruente e inadeguato. Il metodo si basa sul disaccoppia- mento delle e...