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Use of new antiseismic techniques is certainly suitable for buildings of strategic importance and, in general, in the case of very high risk. For ordinary buildings, instead, the cost of base isolation system should be balanced by an equivalent saving in the structure. In this paper the comparison criteria have been first defined, and then a large numerical investigation has been carried out to analyze the effectiveness and the economic suitability of seismic isolation, using elastomeric isolators and sliders, in reinforced concrete buildings.

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There is great effort of planning to rebuild the recently destructed Alhadba minaret in Mosul. A major requirement is to study the original shape and materials. During the past years, there was a considerable amount of leaning in the minaret due to various natural and human causes. The amount of leaning was generally increasing, but there was no unified or fixed control that is referenced from various monitoring groups. This paper describes the effort that was performed to design and implement a monitoring system that can be referred. Fixed control points and targets have been worked. Samples of monitoring results are presented. Data can be used for reconstruction.

Curved surface sliders are being used more and more in the seismic isolation of buildings. They are preferred not only because of their lower cost with respect to elastomeric isolators but also of their technical characteristics, such as the fact that the value of the period of vibration is independent of the mass and the automatic coincidence between the gravity mass center of the superstructure and the stiffness center of the isolation system. In this paper, these features are analysed with reference to simple structures, pointing out the possibility of rotations of the superstructure and the loss of contact in some devices. Finally, the importance of the static friction is also emphasized showing the experimental seismic response of an isolation system under a low-energy earthquake. For all these reasons, the use of nonlinear analysis, revised and detailed in this paper, is advisable for the isolation system made of curved surface sliders.