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Santucci de Magistris, Filippo
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- PublicationRestrictedGeotechnical characterization of the aterno valley for site response analyses(2013)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ;The paper reports about the in-situ and laboratory tests executed in the aftermath of the April 6, 2009 L’Aquila earthquake, aimed at contributing to the definition of geotechnical models for site response analyses in the Aterno valley. The investigation started immediately after the earthquake and was entrusted by the Civil Protection Department to different public institutions and private companies; the experimental activities here reported were coordinated by the Italian Geotechnical Society. In the paper, after briefly depicting the geological setting of the L’Aquila basin and the Aterno river valley, an overview of their subsoil conditions is given, based on the geotechnical tests executed before the 2009 earthquake. Thereafter, the specific investigations planned for the characterization of reconstruction sites and seismic microzonation are widely described. The in situ tests consisted of seismic dilatometer and multi-receiver surface wave tests; the resulting shear wave velocity profiles were compared each other, and against independent Down-Hole tests and ambient noise measurements. The laboratory investigation included cyclic/dynamic simple/torsional shear tests on undisturbed samples. The results, summarized in terms of variation of stiffness and damping with shear strain, highlighted some peculiar properties of the soils in the Aterno valley, which could be related to their index properties.147 4 - PublicationRestrictedExperimental Assessment of the Stress–Strain Behaviour of Leighton Buzzard Sand for the Calibration of a Constitutive ModelA number of constitutive models are nowadays implemented in numerical codes which simulate the stress–strain behaviour of soil from very small to large strain. In this paper, the mechanical behaviour of Leighton Buzzard sand (grade E), used worldwide for physical modelling, has been thor- oughly characterized by laboratory testing along several stress paths. Tests were aimed at calibrating a constitutive model, that allows considering stiffness nonlinearities in a wide range of strains, in the framework of isotropically hardening plasticity. As a validation, the results of dynamic centrifuge tests on a layer of the same sand were compared with finite element predictions.
94 5 - PublicationRestrictedReconnaissance of 2016 Central Italy Earthquake Sequence(2018)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;The Central Italy earthquake sequence nominally began on 24 August 2016 with a M6.1 event on a normal fault that produced devastating effects in the town of Amatrice and several nearby villages and hamlets. A major international response was undertaken to record the effects of this disaster, including surface faulting, ground motions, landslides, and damage patterns to structures. This work targeted the development of high-value case histories useful to future research. Subsequent events in October 2016 exacerbated the damage in previously affected areas and caused damage to new areas in the north, particularly the relatively large town of Norcia. Additional reconnaissance after a M6.5 event on 30 October 2016 documented and mapped several large landslide features and increased damage states for structures in villages and hamlets throughout the region. This paper provides an overview of the reconnaissance activities undertaken to document and map these and other effects, and highlights valuable lessons learned regarding faulting and ground motions, engineering effects, and emergency response to this disaster.175 4 - PublicationRestrictedSPT blow count vs. shear wave velocity relationship in the structurally complex formations of the Molise Region (Italy)(2015)
; ; ; ; ; ; ; ; ;The relationship between the shear wave velocity (VS) and the blow number of the Standard Penetration Tests (NSPT) was investigated with reference to the structurally complex formations located in a wide sector of the Southern Apennine chain (Molise Region, Italy). Novel NSPT–VS correlations were developed, based on a balanced number of in situ tests coming from the seismic microzonation of the municipalities of Campobasso District and the seismic vulnerability assessment of strategic road infrastructures. It was proven that available relationships were not able to fit the data in the area of interest, even making the analysis according to the soil grain size clas- sification. This circumstance was related to the nature of the geological formations, which are chaotically built and affected by complex structural–textural and lithological characteristics. Hence, in this paper, a rational meth- odology for an integrated geological and geotechnical assessment of the available field data based on lithostratigraphical features was presented and discussed. Three original empirical NSPT–VS power function rela- tionships were derived and distinguished depending on the main lithofacies recognized in the Campobasso Dis- trict, corresponding to Structured Soil Deposit (SSD), All Soils (AS) and Weathered Soils (WS). Their validation through statistical assessment of data confirmed the relevance of the results and the advantages related to their use at regional scale, based on an integrated geological and geotechnical approach.71 6 - PublicationRestrictedA geolithological approach to seismic site classification: an application to the Molise Region (Italy)Seismic site classification is a critical issue in order to reliably predict seismic ground motion parameters for the development of microzonation maps and site-specific hazard studies, addressed to territorial planning, real-time generation of shaking maps, and seismic design of engineering structures. The equivalent shear wave velocity through the topmost 30 m (VS30) is commonly assumed as the reference parameter to provide practical site classifications. Different approaches aimed at expressing local site conditions in terms of VS30 exist. Overall geological and morphological characteristics are often suggested in the technical literature as proxy to infer VS30 at a regional scale. In this study, the reliability of two commonly accepted approaches based either on the topographic slope proxy or on a basic geological classification was assessed with reference to a well-documented case study, the Molise Region (Italy). A comprehensive database of Down-Hole tests was collected, validated and processed in order to compare measured VS30 values with those inferred from proxy-based approaches. Furthermore, an up-to-date review of the geology of the area was carried out, and a novel methodology based on a geolithological approach was proposed for site classification at a regional scale. The methodology is based on the definition of a set of homogeneous geolithological complexes, and on their classification according to a statistical analysis of the measured VS30 and of the bedrock depth. Original maps of the seismic ground types were developed following classification criteria based upon the European building code for seismic design (EC8) and relevant modifications proposed in the literature. The comparison of the results obtained by the geolithological approach versus those deriving from the application of the above mentioned proxies pointed out an enhanced capability of the proposed method to fit the distribution of ground types, as assessed on the basis of the VS30 values measured in the reference area.
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