Month: May 2006

  • Uncategorized

    • Adjacent structures controlled by elasto-plastic steel devices

    Giancarlo Fraraccio, Maurizio De Angelis

    In this paper a shaking table test to improve the effectiveness of passive control of adjacent struc- tures by means of hysteretic devices is presented. This configuration might be typically find in civil and industrial applications. The test structure is a 1:5 scaled coupled structures model of different height and mass. The two structures are connected by using elasto-plastic devices. For two adjacent multi degree of freedom systems the problem of optimal design of hysteretic connections is also studied. The model undergoes different earthquakes of different intensity. The control performances of the passive control are compared with both the uncoupled and the rigid-connection structures cases. Results clearly show the good performance of the proposed control approach.

    Available in Italian only.

  • Uncategorized

    • Tests on tuff masonry walls retrofitted by jointed jackets

    Andrea Aquilino, Roberto Colombini, Pierfranco Ventura

    he results of the tests on two masonry specimens in tuff elements bonded by pozzolanic mortar and retrofitting by jointed jacket, in unfavourable conditions, are described. The first test is deruled on originally wall «no jacket», by monotonic shear charge below limit service normal stress. The second test is evolved by cyclic quasi-static shear on masonry improvement with «jointed jacket» steel grid of the limitated surface and no blinded with adjacent ones, connected by tightening bolts for induced triaxial strength.
    Emphasize the isotropic and homogeneous behaviour of the original masonry, in the service state limit in sintony to similar constitutive bond mortar/tuff; in particular the mortar resistance is measured by a new in situ torsional test compared with traditional test. The analysis of experimental data is developped principally by eurocode EC6 for masonry. The stiffness of fissured jacked wall is similar original masonry, and ultimate shear is 40% superior to original monotonic cracking test. The return to the pseudo elastic behaviour after improvement the first cracking, is emphasized from the absence of the permanent displacement and reduced isteretic phenomena in cyclic service state limit, while increase toward the ultimate limit state. The important role in bearing capacity of the friction Coulumbian model and specially cohesion value is back analysed from SLU and SLE before parzialitiation of the wall section, in particular in presence of the foundations settlements and revolution of the collapse moment/shear mechanism.

    Available in Italian only.

  • Uncategorized

    • Linear Static Analysis and Eccentricity

    Matteo Mainetti, Salvatore Noè

    It is shown how the lateral force method of analysis contemplated by the Italian and European Codes is not suitable for describing the behavior of a building subject to seismic action, even under perfect structure regularity. The deficiency of the method is quantified, and the reasons behind it explained, namely the way the eccentricity is taken into account. Finally, an improved lateral force method is proposed, which is as simple as the current one, and at the same time able to fill the gap.

    Available in Italian only.

  • Uncategorized

    • Fast seismic vulnerability assessment for strategic buildings of Campania Region

    Giulio Zuccaro, Francesco Cacace

    In the paper a new procedure to assign residential building structure typologies to seismic vulnerability classes is showed. The procedure, developed within the activities of the Research Project SAVE (Strumenti di Analisi di Vulnerabilità degli Edifici esistenti) supported by National Depart. of Civil Protection trough GNDT- INGV, represents a quick technique that, based on «first level» data (i.e. survey forms as: Abruzzo ’84, GNDT 9/86, AeDES, etc.), evaluates the seismic structural vulnerability by assigning single structures to a building type family of which the behaviour under seismic action is expected. The procedure, although is based on «poor information», introduces several parameters that allow to take into account, in the final vulnerability estimation, all the information possibly available on the structure characteristics about the building (structure types, layout, dimensions, geometry, materials etc.). The procedure has been calibrated using a large data-base containing all the damage data surveyed in several seismic events of the past in Italy, from the Irpinia earthquake in the 1980 up to the Molise earthquake in 2002, considering roughly 165.000 buildings, selected among the over 200.000 in the DB. Finally an application of the procedure to the «public & strategic buildings» in Campania Region is reported, this has been used to define the priority-list for the best allocation of the resources assigned to the Regions from the Ordinance 3362/2003 of the Government that states the strengthening of the most vulnerable strategic buildings in the regions. The results of the punctual sample check «in situ» are reported and a very good reliability of the procedure in this case is showed.

    Available in Italian only.