1,721,163 research outputs found
Response of frames seismically protected with passive systems in near-field areas
No full textThe present paper analyses the behaviour of moment resisting
frames in reinforced concrete subject to earthquakes recorded in near-field
areas. In these areas, the signals show impulsive-type accelerograms, with
velocity and displacement peaks higher than in far-field zones especially for the
fault-normal component of the ground motion velocity in the direction of
propagation of the wave, which shows large-amplitude pulses. In the following,
seven near-field signals scaled in agreement with the design spectrum of the
Italian code (NTC, 2008) have been adopted to perform a nonlinear analysis on
a six-story frame. The response has also been determined for the same frame
protected once with hysteretic-type energy dissipaters and once with base
isolators. The aim of the present study is to acquire quantitative knowledge on
the near-field ground motion effects on frame buildings and on their damage
also in the presence of passive seismic protection system
On the Numerical and Experimental Strengthening Assessment of Tufa Masonry with FRP
No full textIn this paper a constitutive relation of bounded tensile strength function of the strain state of the material is proposed for tufa masonry structures with and without Fiber Reinforced Polymer (FRP) reinforcement. The fiber-reinforcement is modeled as a linear elastic material with no-compression strength. Tests have been performed to verify the proposed model and the efficacy of this structural FRP reinforcement technique for masonry.
Tests have utilized brick specimens, little beam specimens and masonry panels. Results demonstrated the effectiveness of the strengthening technique and the capacity of the constitutive equation to model the behavior of more complex fiber-reinforced masonry structures
Structural Monitoring of Artistic and Historical Building Testimonies
No full textS.M.ART. BUIL.T. “Structural Monitoring of ARTistic and historical BUILding Testimonies” is a project
founded by the European Territorial Cooperation Programme Greece-Italy 2007/2013 and leaded by the
Polytechnic of Bari. The core idea of “S.M.ART. BUIL.T.” is risks prevention, which concerns not only the
prevention of loss of lives and properties, but also the preservation of artistic and historical buildings from
natural hazards.
Architectural heritage is an important part of the history and identity of Italy and Greece, contributing to
their economy and well being. On the other side, ancient buildings suffer a high vulnerability to dynamic
loads, which may induce an unpredictable partial or total collapse. Recent past experience after L’Aquila
earthquake strongly evidence this problem.
The main objectives of the international project “S.M.ART.BUIL.T.” are the implementation of procedures
for the structural monitoring, the seismic vulnerability assessment, the development of guidelines for
strengthening and repair of the historical buildings (in Trani and Corfu). The project aims at providing to
technical officials of the territorial authorities of Puglia and Ionian Islands Regions some indispensable
training tools for the development and/or validation of structural restoration projects and seismic
rehabilitation of historical buildings. Most of buildings of artistic value, in the two historic centers, are
invariably built of masonry, a material as old as the civilization and with a 10,000 years record of success
and lasting qualities, representative of a widespread typology in the Mediterranean area.
The final step has been the International Conference titled “HISTORICAL CENTRES AMONG CULTURE, ART
AND TECHNIQUES: A NEW PARADIGMA FOR RISKS PREVENTION THROUGH STRUCTURAL MONITORING”,
which also represents the most important action of diffusion activities of the S.M.ART.BUIL.T. project.
The Final Conference has been open to all experts in the following topics: seismic and structural
monitoring, historical and artistic heritage, computational and technological issues applied to historical
heritage, in order to exchange experience of correlated research areas. The main purpose has been to
make the conference a forum for dissemination of the latest scientific and technical developments and for
exchange of new ideas in emerging topics of the project.
The main conference topics has been divided into three areas and chapters, following the three main souls
of the project:
1. HISTORICAL AND ARTISTIC AREA
2. STRUCTURAL AREA
3. COMPUTATIONAL AND TECHNOLOGICAL ARE
Risposta di telai protetti con dissipatori di energia da terremoti in zone prossime alle faglie
No full textOn the Optimum Placement of Dissipators in a Steel Model Building Subjected to Shaking-Table Tests
No full textThe following research presents the numerical and experimental results obtained on a reduced scale steel model
of a medium-rise building structure dynamically protected with energy dissipaters. The steel-steel friction dissipates energy
as the structure undergoes interstory drifts. A preliminary numerical analysis is performed to determine the best position
of the friction dampers in the longitudinal frames. All the nodes of the numerical model have been assumed with the
same bending stiffness. Shaking table tests have been performed, both in random vibration tests (to determine the natural
periods and the dynamic characteristics of the model) and in earthquake simulation tests (to study the dynamic behaviour
of the model with and without dampers). The results have been compared to those achieved during a previous experimental
study based on the same model protected with only one friction damper for each longitudinal frame
Shear Vulnerability of Historical Reinforced-Concrete Structures
No full textModern buildings have been characterized by the rapid spread of reinforced concrete as a novel and
versatile building material. Within the assessment of existing buildings, the most sensitive structures
are those designed in the first half of the last century, when the theory of reinforced concrete and the
detailing rules were not well established yet. This study considers the issues related to the gradual
understanding the vulnerability at a territorial scale of structural typologies designed only to vertical
loads. In particular, the shear behavior of the buildings in the period between 1920 and 1960 is
investigated. Subsequently, the shear strength control of the structural elements of an open air stadium
in the South of Italy is carried on according to Eurocode 2, the American code, ACI 318-08 and a
method based on Arslan’s equation. The results are compared with those included in the original
calculus report according to R.D.L. 18/7/1930 decree
On the dynamic behavior of a new shear dissipater for the seismic protection of structures
No full textThe present paper describes a new dissipation device
that can be utilized to reduce the seismic effects on civil engineering
structures and preserve their structural integrity. The new device is
made of aluminum and steel; it dissipates energy through the
hysteretic behavior and the local plasticization of aluminum. It is a
very simple device with a low cost of production. The proposed
dissipater has been first tested using a monotonic type load in order
to characterize it and to determine its mechanical parameters. Then
its capacity to dissipate energy has been confirmed by a series of
shaking-table tests on a 3D steel frame protected with these new
devices. The frame has been subjected to a series of records from an
impulsive earthquake such as Aigio allowing to determine the nonlinear
behavior of the dissipaters under severe working conditions,
and to assess the efficiency of the device
A new experimental approach to the pushover analysis of masonry buildings
No full textThe present paper proposes a new approach for the pushover analysis of masonry structures: the shear
strength of a masonry building is determined using experimental values combined with an analogy with
rock masses. The shear strength criterion of Mohr–Coulomb is used, the values for the cohesion and friction
angle being obtained by the non-linear criterion of Hoek–Brown for rock masses. The results of the
proposed method are in good agreement with the values of the shear strength obtained using the Italian
Code (NTC 08) for an LC3 level of knowledge of a masonry structure
Isolatore Sismico
No full textThe device is capable of reducing and attenuating, the effects of an earthquake on a building or a construction in general. The basic idea is to use two layers of cylindrical rollers. The first group is over the second group and rolls in a direction perpendicular to the previous one.
Therefore, any tangential force induces a rolling of the cylinders so as to have a decoupling of the motion of the base from the structure, with a reduction and/or cancellation of the seismic acceleration in the structure.
Two respective cradle house the groups of rollers, and each cradle presents a vulcanized layer of high damping rubber in contact with the cylinders in order to increase the dumping of the structure.Il dispositivo è in grado di ridurre e attenuare, gli effetti di un terremoto su un edificio o, in generale, su una costruzione. L'idea di base è quella di utilizzare due serie di rulli cilindrici disposti su due livelli, con direzione di rotolamento perpendicolare fra loro.
Pertanto, qualsiasi forza tangenziale agente sul dispositivo produce un rotolamento dei cilindri, in modo tale da avere il disaccoppiamento del moto della base da quello della struttura, con riduzione e/o annullamento dell’amplificazione dell’accelerazione sismica nella struttura.
I due gruppi di rulli rotolano su due rispettive culle e sulla superficie di ogni culla è vulcanizzato uno strato di gomma ad elevato smorzamento; i cilindri, rotolando sulla gomma, producono un aumento dello smorzamento del sistema
Use of recycled waste PET bottles for the reinforcement of concrete
No full textIn the present paper the results of some tests performed on concrete specimens reinforced with fibers made from waste polyethilene terephthalate (PET) bottles are reported. The fibers have been obtained by simply cutting the bottles; the fibers are then added to the mix concrete or they are used as discrete reinforcement of specimens and little beams in substitution of steel bars. The tests are to be considered as an approach to a more extensive investigation on the use of PET as a reinforcing material for concrete and masonry structures. The results that have been obtained are very interesting, especially regarding the adherence between PET and concrete, suggesting a possible use of this material in the form of flat or round bars, or networks for structural reinforcement
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