Teresa Crespellani

Influence of uncorrected accelerogram processing techniques on Newmark's rigid block displacement evaluation

Design seismic motion represents a fundamental issue of many geotechnical applications. In more complex numerical procedures, input motion is required in the complete form of an accelerogram, whereas in simplified prediction methods it is generally expressed by means of synthetic parameters such as peak ground acceleration, peak ground velocity, Arias intensity, etc. The aim of this paper is to show the sensitiveness of these parameters to small changes in the characteristics of the accelerogram associated with the filtering procedures used for reducing digitisation errors, instrument distortions, etc. and the influence of the consequent uncertainties on geotechnical applications. More specifically this paper examines the incidence of processing techniques of uncorrected records from Italian accelerograph network on slope displacement evaluation based on Newmarks rigid block model.

Influence of Soil Dynamic Parameters on Seismic Response of a Site at Fabriano, Italy

1 Dipartimento di Ingegneria Civile, Universita di Firenze, Italy – teresa@dicea.unifi.it 2 Dipartimento di Ingegneria Strutturale e Geotecnica, Politecnico di Torino, Italy diego@geohp.polito.it 3 Dipartimento di Ingegneria Civile, Universita di Firenze, Italy 4 Dipartimento di Ingegneria Civile, Universita di Firenze, Italy INFLUENCE OF SOIL DYNAMIC PARAMETERS ON SEISMIC RESPONSE OF A SITE AT FABRIANO, ITALY

Seismic microzonation: an essential tool for urban planning in seismic areas

Dramatic images of heaps of rubble produced in Italy by destructive earthquakes show the extreme vulnerability of urban systems and territory and the need for urgent measures to protect citizens, buildings, artistic heritage and landscape. According to this study, the reduction of vulnerability must go through ordinary city planning tools, prepared in time of seismic silence. They must be a strong reference point also for reconstruction. Therefore, a correct planning in seismic areas must be based on a deep knowledge of the territory, of its physical, historical and cultural characters. In this context, the studies of seismic microzonation have a central role in providing information about amplification phenomena linked to the interactions between seismic waves and soils and they are indispensable to manage an extraordinary event with ordinary urban planning instruments, as might be wished in an advanced nation.

Dynamic Soil Properties and Site Coefficients for Aseismic Building Design in Some Typical Soil Deposits of the Marche Region, Italy

bstract— Although in Central Italy seismicity is lly moderate and the maximum expected local Richter tudes are about 6-6.5, in the past many urban ents and villages have experienced, even during low ity earthquakes, very severe damage, which can be ted to the sharp topography or the presence of thick ts or the particular dynamic properties of the soils. fore, in order to provide new updated guidelines for c building design, great research effort has been aimed quantification of site responses in various Italian ical centres over the latest years. Moreover, since ode 8 (EC8) will be adopted within a short period in ies of the European Union, these studies have also aimed at controlling reliability of EC8 spectra for sites. This paper describes the research developed for fects evaluation at Offida, a historical centre in The e with important monuments and environmental ge. A specific program of seismological investigations, ting in measuring low amplitude earthquakes and tremors, and geotechnical testing, including boreholes, ic field and laboratory tests, was carried out. A y of methods were utilised and compared, considering nt earthquake scenarios and ground motions. The ed spectra were finally compared with those proposed rocode 8.

Protezione sismica di alcuni centri di interesse storico culturale in Garfagnana : il caso di Castelnuovo Garfagnana

Seismic protection of historical urban nuclei in Garfagnana: an example Garfagnana region was repeatedly struck by destructive earthquakes up until quite recently. The region is mainly mountainous and very rocky, and is crossed by different systems of active faults. Many urban nuclei are situated on steep hillside and along deep valleys. The morphological and geotechnical conditions are favourable for producing topographic and stratigraphic amplification effects. The physical phenomena associated to these effects, generally disregarded in risk analyses on large scale and from the Italian seismic building code, have been object, in the last twenty years, of extensive research of the scientific community. The present research describes a few preliminary analyses for the site effects evaluation in the historical centre of Castelnuovo Garfagnana.

Investigation of the Seismic Soil-Structure Interaction on a Concrete Instrumental Building

SUMMARY Experience has shown that soil-structure interaction can play an important role on structural behaviour during earthquakes. A complete soil-structure interaction analysis consists of two parts: a site response analysis for free field motions and an interaction analysis for structural response. In the present study the effects of soil-structure interaction are evaluated on a two-storey concrete building about 10 m high with a rectangular horizontal section of about 11m x 28 m. The building, of public interest, is equipped with several accelerometers. The structure and the foundation system were idealised by a 3-D finite elements model, while the underlying soil is represented by a semi-infinite visco-elastic 1-D model. The soil-structure interaction analysis was performed by using the substructuring method implemented by the SASSI2000 numerical code. The accelerograms recorded during a low magnitude earthquake (ML = 4) by a free field seismic station, about 5m away from the building, were adopted as the seismic input motion. In this paper the results of the numerical analyses obtained in some significant nodes of the structure are presented both in time and frequency domain, and compared with the seismic recordings; moreover the influence of the structure on the ground motion is evaluated by comparing the free field actual motion with the numerical modelling results at the boundary between the soil and the foundation.

Seismic Response and Soil-Structure Dynamic Interaction for a Large Building in Florence

The New Law Court in Florence, the construction of which is under way, consists of buildings of different heights, up to a maximum of 77 m from g.l. It covers an area of about 30,000 m, and has a total volume of 750,000 m, approximately 550,000 m of which are above ground level. Figure 1 reproduces a photograph of the plastic model of the building in progress. The foundation soil is part of a very thick recent alluvial deposit (more than 80 m) consisting mostly of consistent and overconsolidated silts and clays, with local inclusions of pebbles, gravel and calcareous nodules with dimensions that are even centimetric, more frequently in the first 20 m of depth. Thorough geotechnical studies were carried out (Vannucchi, 1997; 1999) in view of the importance of the work. In particular, the local seismic response in a free field was evaluated, and an analysis of the soil structure dynamic interaction was made. The results of these analyses are discussed synthetically here as follows. 2 CHARACTERISTICS OF THE DESIGN MOTION