Static and dynamic soil characterization at Roio Piano (AQ)

Following the 6 April 2009 earthquake which hit the Abruzzo region, numerous static and dynamic field soil characterizations have been performed, in order to analyze the seismic response of soils (GRASSO et al. 2005, LANZO et al., 2011, MAUGERI et al., 2011) and recover or retrofit buildings and important historical monuments. Among the numerous on-site investigations which took place in different parts of L'Aquila province, this paper reports the site investigations at Roio Piano. In particular, the results from in situ Seismic Dilatometer Marchetti Tests (SDMT) and soil laboratory tests are reported. As regards dynamic laboratory tests, the resonant column test was used to evaluate the soil geotechnical parameters in terms of the shear modulus G-γ and damping ratio D-γ

Geotechnical and Seismic Risk Evaluation in Urban Areas

Seismic and geotechnical hazard problems are widespread all over the world and they can cause natural disasters, damaging properties or causing human lives losses. Italian municipalities are not yet organised either to deal with the phenomena consequences, or to plan risk mitigation actions. A clear knowledge of the location and of the space and time evolution of the phenomena is needed for a vulnerability mitigation in the probably involved areas. Geo-hazard can be related with the consequences for exposed people and man made work by a microzonation. GIS technologies could play a crucial role in analysing large areas, but a good geodatabase should be designed and populated with all the available data. In this work, an approach to detect geotechnical hazard factors and vulnerability elements of urban areas is presented. A geodatabase is designed in terms of conceptual and logical model. A multy-risk analysis is carried out, pointing out geotechnical seismic and hydrogeological risk. Expressly created forms are proposed, that include specific sections regarding buildings, infrastructures and lifelines for vulnerability detection. Some applications in central Sicily (Italy) are shown. From such a analysis, Civil Defence and Local Authorities could obtain a continuous stream of information and integrate them into models for hazard knowledge, vulnerability mitigation and risk prevention

experimental study on native plant root tensile strength for slope stabilization

Abstract The use of plants for protection of slopes or river embankments against water and wind erosion is spreading in civil and environmental engineering. Naturalistic approach for slope stabilization has been more and more studied and experimented, and a genuine discipline, that integrates traditional geotechnical engineering methods, has been created: Bioengineering. To evaluate plants roots effect on soil shear strength and slope stability, theoretical and experimental studies about biotechnical and mechanical characteristics are needed, to better understand soil-root interaction mechanism. This work provides indications on mechanical strength parameters of some species of native plant roots. Tensile strength of two Mediterranean species have been analyzed caring out a series of experimental tests. Results indicate that tensile strength of roots is influenced by many factors, among which, the most important are root diameter, its moisture and the location where plants had grown up

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

This study is part of a more extensive research aimed to the seismic risk mitigation in Eastern Sicily. The earthquakes that occurred in Sicily in 1169, 1542, 1693, 1818, 1908 and more recently in 1990, testify the high level of seismic hazard in this region. It is well recognized that local seismic effects can exert a significant influence on the distribution of damage during earthquake. Traditionally, these effects are studied by means of simple one–dimensional (1-D) models of seismic wave propagation, which take only the influence of the stratigraphic profile and soil proprieties into to account for the site seismic response. It is known that the seismic response is strongly influenced by stratigraphic and topographic features that can reduce or amplify the earthquake induced ground motion depending on the soil stiffness and on the ground topography. This paper concerns the results of a two-dimensional (2-D) finite element analysis carried out to evaluate the response of the site where the National Institute of Geophysics and Volcanology (INGV) building is located in the town of Catania. The analysis, performed using as seismic input the accelerogram recorded in 1990 during the Santa Lucia earthquake, allowed to make some considerations about the expected accelerations at that the site and some comparison with the peak accelerations prescribed by Italian seismic code

Site seismic response for a strategic building in the city of Messina by two-dimensional finite element analysis

It is well recognized that local seismic effects can exert a significant influence on the distribution of damages during earthquakes. Traditionally, these effects have been studied by means of simple one-dimensional (1-D) models of seismic wave propagation which take only the influence of the stratigraphic profile and soil/bedrock properties into account on the seismic response. Conversely, local effects derived from surface topography such as ridge, cliffs etc., which are typically two-dimensional (2-D) and three-dimensional (3-D) problems, have received less attention because of computational time, lack of experimental data and the need of more refined models. It is therefore of great interest to quantitatively evaluate the relative contribution on seismic response of stratigraphic as well as of topographic effects, which can be very different depending on the specific morphological conditions and geotechnical characteristics of the site

Numerical analysis of a full scale earth reinforced wall: Static and seismic behavior

Attualmente sono disponibili molteplici tipologie di muri in terra rinforzata. Una delle tipologie più interessanti è rappresentata dai muri a parete verticale con rinforzi polimerici nastriformi e con pannelli di facciata in calcestruzzo. La rigidezza a trazione di questi rinforzi è molto più grande di quella dei rinforzi geosintetici usuali e una delle incertezze che possono insorgere è se tali rinforzi possono essere considerati estensibili o inestensibili. Lo scopo del presente lavoro è dare un contributo per una migliore comprensione del reale comportamento di tali rinforzi polimerici. Allo scopo è stato realizzato un muro sperimentale in vera grandezza in cui sono stati utilizzati rinforzi nastriformi denominati “ParaWeb”. Il muro è stato strumentato al fine di misurare deformazioni e tensioni sui rinforzi come anche le pressioni prodotte dal terreno. Come confronto con i risultati sperimentali è stata condotta un’analisi bidimensionale agli elementi finiti per simulare il comportamento del muro. I risultati sperimentali e analitici sono stati messi a confronto fra loro in condizioni di carico statico al fine di individuare gli aspetti peculiari del comportamento di tali muri rinforzati con “ParaWeb” e per validare le analisi numeriche. Infine è stata fatta una previsione del comportamento di tali muri sotto carico sismico. Parole chiavi: analisi FEM; terra rinforzata; metodi di progettazione; analisi statica; analisi sismica.Nowadays several reinforcal earth typologies are available. One of the most interesting is the vertical earth walls reinforced with polymeric geostrips with concrete facing panels. Geostrips tensile stiffness is much larger than that of typical geosynthetic sheets. Uncertainties may arise about the real geostrips behaviour: if they should be considered as inextensible or extensible. The aim of this work is giving a contribution to better understand the real behaviour of such polymeric geostrips. An experimental full-scale model of reinforced soil wall was built applying the quoted technology. The experimental model was fully instrumented to measure both stress and deformations on strips and to investigate about earth pressure. The Authors carried out a two-dimensional (2D) FEM analysis to simulate the wall performance. Experimental, numerical and analytical results have been compared in static condition, in order to detect the main aspects of the behaviour of soil walls reinforced with polymeric geostrips and to validate numerical analysis. Then, a prediction of the behaviour of the wall under seismic loading has been assessed

Earthquake Geotechnical Engineering Aspects of the 2012 Emilia-Romagna Earthquake (Italy)

On May 20, 2012 an earthquake of magnitude ML=5.9 struck the Emilia Romagna Region of Italy and a little portion of Lombardia Region. Successive earthquakes occurred on May 29, 2012 with ML=5.8 and ML=5.3. The earthquakes caused 27 deaths, of which 13 on industrial buildings. The damage was considerable. 12,000 buildings were severely damaged; big damages occurred also to monuments and cultural heritage of Italy, causing the collapse of 147 campaniles. The damage is estimated in about 5-6 billions of euro. To the damage caused to people and buildings, must be summed the indirect damage due to loss of industrial production and to the impossibility to operate for several months. The indirect damage could be bigger than the direct damage caused by the earthquake. The resilience of the damaged cities to the damage to the industrial buildings and the lifelines was good enough, because some industries built a smart campus to start again to operate in less of one month and structural and geotechnical guidelines were edited to start with the recovering the damage industrial buildings. In the paper a damage survey is presented and linked with the ground effects. Among these, soil amplification and liquefaction phenomena are analyzed, basing on the soil properties evaluation by field and laboratory tests. Particular emphasis is devoted to the damaged suffered by the industrial buildings and to the aspects of the remedial work linked with the shallow foundation inadequacy and to the liquefaction mitigation effects

Site characterization by dynamic in situ and laboratory tests for liquefaction potential evaluation during emilia romagna earthquake

To investigate the geotechnical soil properties of Emilia Romagna Region, a large series of in situ tests, laboratory tests and geophysical tests have been performed, particularly at the damaged city of Scortichino—Bondeno. Deep site investigations have been undertaken for the site characterization of the soil also along the Burana-Scortichino levee. Borings, Piezocone tests (CPTU) and dynamic in situ tests have been performed. Among them, Multichannel Analysis of Surface Waves test (MASW) and Seismic Dilatometer Marchetti Tests (SDMT) have been also carried out, with the aim to evaluate the soil profile of shear wave velocity (Vs). Resonant Column Tests (RCT) were also performed in laboratory on reconstituted solid cylindrical specimens. The Seismic Dilatometer Marchetti Tests were performed up to a depth of 32 m. The results show a very detailed and stable shear wave profile. The shear wave profiles obtained by SDMT have been compared with other laboratory tests. A comparison between the in situ small shear strain, laboratory shear strain and shear strain obtained by empirical correlations, was also performed. Finally, using the results of SDMT tests, soilliquefaction phenomena have been analyzed with a new procedure based on SDMT, using the soil properties obtained by field and laboratory tests