199,657 research outputs found
Janice J. Foti to Jennifer M. Porter
No full textLetter from Janice K. Foti, Acting Director, Office of Oceans and Polar Affairs, Bureau of Oceans and International Environmental and Scientific Affairs, [United States] Department of State to Ms. Jennifer M. Porter, Second Secretary, Australian Embassy, January 18, 1980https://lawcommons.lclark.edu/iwc_correspondence_1-6/1025/thumbnail.jp
Jennifer M. Porter to Janice J. Foti
No full textLetter from Jennifer M. Porter, Second Secretary, [Australian Embassy] to Ms. Jan [Janice] Foti, [Acting Director], Office of Oceans and Polar Affairs, [Bureau of Oceans and International Environmental and Scientific Affairs, United States Department of State], January 15, 1980https://lawcommons.lclark.edu/iwc_correspondence_1-6/1026/thumbnail.jp
Optimal design of a new seismic passive protection device made in aluminium and steel
No full textIn recent years many techniques for the seismic control of structures have been developed. Among these, the metallic hysteretic devices are able to dissipate a great amount of the energy entering the building during a seismic event, thanks to a stable behavior under cyclic loads that produces a wide hysteretic loop. Steel shear panels are examples of elasto-plastic elements, which dissipate energy under a shear behavior. Generally such dampers are known to possess large energy-dissipation capacity relative to their size; they are cost-effective and are able to protect non-structural elements too. Moreover, the shear panels may be easily installed and substituted in the structure by mean of diagonals on which may be mounted and then connected to the frame. As disadvantage, this kind of energy dissipating devices can dissipate energy only after they sustain inelastic excursions. As a consequence they are ineffective for vibrations that produce interstory drifts smaller than the yielding drift of the device. To overcome this constraint, Rai and Wallace and Foti and Diaferio proposed shear panels made in aluminium alloys. In fact, these alloys are very ductile with a yielding limit lower than ordinary steel. Numerical and experimental researches have been developed on aluminium shear links. Foti and Nobile performed characterization and shaking-table tests on some aluminium shear panels showing instability phenomena and problems of the connections of the devices to the structure.
The aim of the present note is to find out the optimum geometrical configuration of an aluminium-steel shear panel in order to dissipate a large amount of the seismic energy
Non-destructive techniques and monitoring for the evolutive damage detection of an ancient masonry structure
No full textIn the present article non-destructive testing evaluation of the existing damage evolution
has been applied to some buildings of the medieval town of Craco (Matera, Italy) and, in particular,
to the Normand tower. Actually the little town of Craco is totally abandoned as a consequence of
the activation of the landslide motions of its soil depth. Nevertheless, the Normand tower still
stands because it is located on a stable and stiffer foundation ground.
The tower was built in the XII century. It is 20 m tall and has a symmetric square plan, with
dimensions 11 m x 11 m; it was built for defense against enemy attacks.
Inside the tower a cistern in reinforced concrete was placed in 1949. It is not connected to the
structural walls of the tower; however it represents an obstacle for installing the damage detection
equipment and sensors.
In this article a preliminary study on the masonry structure of the Normand tower is carried on.
A finite element numerical model has been developed and a modal analysis has been performed.
The final aim of the research is to find out the evolutionary stage of the cracks and to propose a
possible retrofit of the tower
Estimation of the hydraulic parameters of unsaturated samples by electrical resistivity tomography
No full textIn situ and laboratory experiments have shown that electrical resistivity tomography (ERT) is an effective tool to image transient phenomena in soils. However, its application in quantifying soil hydraulic parameters has been limited. In this study, experiments of water inflow in unsaturated soil samples were conducted in an oedometer equipped to perform three-dimensional electrical measurements. Reconstructions of the electrical conductivity at different times confirmed the usefulness of ERT for monitoring the evolution of water content. The tomographic reconstructions were subsequently used in conjunction with a finite-element simulation to infer the water retention curve and the unsaturated hydraulic conductivity. The parameters estimated with ERT agree satisfactorily with those determined using established techniques, hence the proposed approach shows good potential for relatively fast characterisations. Similar experiments could be carried out on site to study the hydraulic behaviour of the entire soil deposi
Ambient vibration testing and operational modal analysis of a historic tower
No full textAn accurate knowledge of the dynamical parameters of structures is definitely useful for seismic assessment and for the design of risk mitigation interventions. In this paper, the opportunities provided by dynamic identification techniques for the non-destructive evaluation of heritage structures are discussed with focus on the bell tower of Announziata (Corfù, Greece), a masonry tower, which shows a high damaged scenario and, consequently, a high vulnerability to dynamic and seismic forces. The paper presents the experimental investigations and operational modal analysis results, useful for defining the finite element model of the tower. The monitoring system consists of several elements properly connected: in total twenty-four accelerometers have been positioned, eight for each of the three floors and oriented according to the orthogonal directions x and y. This configuration has been also conditioned by many operative problems about the position of the instrumentation due to the limited accessibility of the structure, not only to the main access but also to reach the top. It is important to emphasize that the data obtained are not connected to external events detected during the acquisitions, so it is possible to identify with a certain confidence the first six frequencies of the tower and their corresponding mode shapes
Identification of the Modal Properties of a Building of the Greek Heritage
No full textIn this paper, the experimental modal identification analysis of the public building “San
Giacomo” in Corfu (Greece) is illustrated. It represents the unique example of a structure built
utilising carves stones inside the city of Corfu. The building has a rectangular plan shape with
dimensions 24.75 x 14 m, and height 9 m; all the floors are made by wood. The monitoring system
consists of several elements properly connected: the units of acquisitions or piezoelectric
accelerometers (in total 18 installed on the different walls) with a sensitivity of 1000 mV/g; the data
acquisition system or DAQs positioned at each monitored level; the laptop with an acquisition
software; the cables that connect all elements to each other.
The paper describes the phases of the investigations, the technical details of the performed in-situ
tests, the first identified frequencies of the building by means of the classical methods of
Operational Modal Analysis (OMA) and the comments about the acquired data
La responsabilità precontrattuale
No full textIl seminario ha avuto ad oggetto il tema della responsabilità precontrattuale, muovendo dall'esegesi dell'art. 1337 del codice civile. Si sono poi approfonditi il ruolo della clausola generale di buona fede e la natura della responsabilità precontrattuale, alla luce dell'evoluzione dottrinale e giurisprudenziale in materia
- …
