Some Experimetnal Evidences on Dynamic Soil-Structure Interaction

Section: Two Dimensional Dynamic Finite Ele Ment Analysissupporting

confidence: 85%

Two-dimensional site seismic response analysis for a strategic building in Catania

Capilleri¹,

Massimino²,

Motta³

et al. 2018

“…The latter approach definitely represents an important step forward [Capilleri et al, 2003[Capilleri et al, , 2005Ferraro et al, 2016Ferraro et al, , 2018Grasso and Maugeri, 2014;Castelli et al, 2018a,b], taking into account the specific conditions of subsoil and its fundamental filtering effects in terms of PHA and predominant frequency. Nevertheless, dynamic response at the foundation level of a structure deviates from the FF site response, because of kinematic and inertial interaction [Gazetas, 1991;Massimino et al, 2015;Abate et al, 2017a, b;Karatzetzou et al, 2017] and in different cases dynamic soil-structure interaction (DSSI) could be detri-mental for the structures [Mylonakis et al, 2000;Pandey et al, 2012]. In order to evaluate the effective ground motion at the foundation level it is necessary to investigate Dynamic Soil-Structure Interaction (DSSI).…”

Section: Introductionmentioning

confidence: 99%

Dynamic behaviour of coupled soil-structure systems by means of FEM analysis for the seismic risk mitigation of INGV building in Catania (Italy)

Massimino¹,

Abate²,

Corsico³

et al. 2018

Seismic design of new structures, as well as retrofitting and/or improving of existing ones should be definitely considered a multidisciplinary subject, which depends on many factors, such as: local site effects and the dynamic interaction between the foundation soil and the structure. The accurate investigation on the structure and the surrounding soil is the first fundamental step for a realistic evaluation of the structure seismic performance. The present paper deals with the Dynamic Soil Structure Interaction (DSSI) analysis concerning the INGV (National Institute of Geophysics and Volcanology) building in Catania, by means of a FEM 2D modeling. The building is a prestigious masonry structure situated in an area characterized by a high seismic hazard. Several accelerograms scaled at the same PHA, with reference to the estimated seismicity of Catania, have been adopted. Soil properties were carefully investigated by means of static and dynamic in-situ and laboratory tests. Many investigations were also performed on the structure. Equivalent linear visco-elastic constitutive models have been adopted both for the soil and the structure. For considering soil nonlinearity, degraded shear modula (G) and increased soil damping ratios (D) have been evaluated for all the involved soil layers, according to two different approaches. Firstly, soil nonlinearity has been modeled basing on the EC8 [2003] suggestions; secondly, it has been modeled choosing the values of G and D according to the effective strain levels obtained for each soil layer and for each different input, by means of an iterative sub-routine. The dynamic response of the system has been analyzed in the time and frequency domains. Results are presented in terms of: acceleration amplification factors, Fourier and response spectra, amplification functions and shear forces per floor. The main goals of the paper are: i) to investigate the acceleration profiles along the soil and the structure considering and not considering the DSSI; ii) to investigate the soil filtering effect in terms of predominant frequency considering and not considering the DSSI; iii) to compare the obtained results with the ones given by a simpler 1D free-field soil analysis; iv) to compare the soil amplification factors and the response spectra obtained by 1D and 2D models with that by the Italian technical code [NTC, 2008]; v) to highlight the influence of DSSI in the seismic response of the structure; vi) to evaluate the influence of different modeling of soil nonlinearity on the dynamic response of the soil and structure.

“…Results of Resonant Column Tests (RCT) and Cyclic Loading Torsional Shear Tests (CLTST) are presented in Figures 6-8 to evaluate the shear modulus G and damping ratio D variation with the shear strain level γ. These tests are fundamental for the accurate evaluation of local site response analyses, as well as for the evaluation of the dynamic behavior of fullcoupled soil-structure systems [Abate et al, 2007;Massimino et al, 2015]. The specimen was anisotropically reconsolidated to the best estimate of the in situ effective vertical and horizontal stress.…”

Section: Geotechnical Site Characterisationmentioning

confidence: 99%

Site effects evaluation in Catania (Italy) by means 0f 1-D numerical analysis

Ferraro¹,

Grasso²,

Massimino³

2018

In the period 2014-2016, a Project financed by the European Community was carried out to investigate the seismic hazard of some areas in eastern Sicily. Within this project, four strategic test sites in Messina [1) and Catania (3) have been studied, because of the fact that these cities are at high seismic risk [Abate et al., 2006; 2017]. Messina suffered the destructive earthquake of 1908 that caused thousands of deaths, injured and displaced, while Catania suffered, since 1169, a number of destructive earthquakes, among which we mainly remember the earthquakes of 1169, 1693, 1818 and 1990 [De Rubeis et al., 1991]. In order to study the dynamic characteristics of soils in three Catania test sites, laboratory and in situ investigations have been carried out to obtain soil profiles with special attention being paid to the variation