Nunziante Squeglia

Nunziante Squeglia
University of Pisa | UNIPI · Department of Civil and Industrial Engineering

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75
Publications
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460
Citations

Publications

Publications (75)
Article
Full-text available
Numerical models play a crucial role in the study and understanding of cultural heritage structures, serving as valuable tools for predicting their behavior under diverse and prospective scenarios. They are however affected by various uncertainties, which impact can be mitigated through the calibration of model parameters. For heritage structures,...
Data
Finite element analysis of operating buried pipelines subjected to strike-slip fault movement
Chapter
The key factors governing the lateral response of a pile group include the pile-head connection rigidity, the pile-soil relative stiffness, the pile spacing ratio, the pile group size and the pile/soil nonlinear response. Since the earlier experimental observations of the existence of group effects it is commonly assumed that the efficiency of a pi...
Article
Permeability and strength parameters of compacted soils (i.e., levees as well as other earthworks) may be correlated to the degree of compaction. Since the use of conventional and recent testing methods for the assessment of density and water content of earthworks, under construction, cannot be applied to existing levees, an expeditious and accur...
Article
A new code, called PRaFULL (Piled Raft Foundation Under Lateral Load), was developed for the analysis of laterally loaded Combined Pile Raft Foundation (CPRF). The proposed code considers the contribution offered by the raft-soil contact and the interactions between all the CPRF system components. The nonlinear behaviour of the reinforced concrete...
Article
Soil-pile kinematic interaction develops as a consequence of soil movements during seismic excitations. Severe bending strains exceeding the strain limits of the pile material can then develop. The highest kinematic bending moments occur at the interface of layered soil, characterized by consecutive layers with a high V s2 /V s1 ratio between their...
Chapter
The paper focuses on the global instability of levees by analyzing those factors that contribute to the earthwork stability. Moreover, the effectiveness of naturalistic methods is reviewed. Global instability is caused by gravity and seepage forces. Therefore, different collapse mechanisms such as piping, overtopping, hydraulic heave, etc. are not...
Conference Paper
The knowledge of fixed-head long piles response mechanism under harmonic excitations and earthquakes significantly increased in the last decades. Most of seismic codes suggest considering kinematic interaction for specific structures, in layered soil with high stiffness contrast and in case of high seismic input. More recently has been shown the im...
Conference Paper
Usually, pile foundations are designed solely to resist the axial load. This simple approach neglects the effects of static, cyclic and/or dynamic lateral loads. Pile-soil interaction during a real earthquake is still now an open issue to be solved and the problem complexity increase in case of liquefiable soil conditions. Despite some methods are...
Conference Paper
Recent studies showed that kinematic interaction is relevant for the design of large-diameter concrete piles in soft soils both in homogeneous and layered deposits. Especially , it was found that exists a range of admissible pile diameters able to resist to combined inertial and kinematic bending at the pile-head. Most of these studies assume that...
Article
Full-text available
The Tower of Pisa has survived several strong earthquakes undamaged over the last 650 years, despite its leaning and limited strength and ductility. No credible explanation for its remarkable seismic performance exists to date. A reassessment of this unique case history in light of new seismological, geological, structural, and geotechnical informa...
Conference Paper
Full-text available
Doctoral schools in Italy began on middle 80s. Since that the objectives and fundamental rules for the third level of Higher Education in Italy changed several times. The paper shows the legislative evolution and reports, in a narrative way, the experience of 5 Ph. D. in Geotechnical Engineering over a period of 30 years (from 1987 to 2017). The na...
Article
It is of fundamental importance in engineering design practice to accurately evaluate the structural response of buried pipelines subjected to seismic hazards, like landslides, lateral spreading due to liquefaction, and faulting, because these seriously threaten pipeline safety. The present paper investigates the seismic performance of a buried ope...
Conference Paper
Full-text available
The Leaning Bell Tower of Pisa has been included in the list of the World Heritage Sites by UNESCO since 1987. Over the last 20 years, the Tower has successfully undergone a number of interventions to reduce its inclination. The Tower has also been equipped with a sensor network for seismic monitoring. In this study, preliminary results on the dyna...
Article
Full-text available
This article introduces a new procedure to model two cases related to the simulation of the movements of the Tower of Pisa: installation of micropiles and soil extraction. Standard FEM requires geometry definition in the initial configuration. In this case the initial configuration is much different from the final one. m-PISE procedure overcomes th...
Article
Full-text available
The Leaning Tower of Pisa was built between 1173 and 1360 and began to lean at the beginning of its construction. Extensive investigations to reveal the causes of the tilting only began in the early 20th century. Although few earthquakes have been recorded, there is a renewed interest in the seismic behavior of the tower triggered by the availabili...
Article
Earthquake induced Permanent Ground Deformation (PGD), such as landslides, lateral spreading due to liquefaction and faulting, seriously threaten the safety of buried pipelines, highlighting the need to accurately evaluate their seismic performance within the engineering design practice. Over the last decades, this problem has been addressed numeri...
Article
Full-text available
A Boundary Element Method (BEM) approach was developed for the analysis of pile groups. The proposed method includes: the non-linear behavior of the soil by a hyperbolic modulus reduction curve; the non-linear response of reinforced concrete pile sections, also taking into account the influence of tension stiffening; the influence of suction by inc...
Article
Full-text available
In high seismicity areas, it’s important to consider kinematic effects to properly design pile foundations. Kinematic effects are due to the interaction between pile and soil deformations induced by seismic waves. One of the effect is the arise of significant strains in weak soils that induce bending moments on piles. These moments can be significa...
Article
This Technical note summarizes some experimental results concerning the effective strength parameters (c' - ϕ') and the saturated coefficient of hydraulic conductivity (k) of silty and sandy soil specimens that have been compacted at different compaction degrees. The tested soils were used for the construction/refurbishment of existing levees. The...
Article
Full-text available
Permeability and strength parameters of compacted soils (i.e., levees as well as other earthworks) may be correlated to the degree of compaction. Since the use of conventional and recent testing methods for the assessment of density and water content of earthworks, under construction, cannot be applied to existing levees, an expeditious and accurat...
Article
Full-text available
A hybrid BEM-p-y curves approach was developed for the single pile analysis with free/fixed head restraint conditions. The method considers the soil non-linear behaviour by means of p-y curves in series to a multi-layered elastic half-space. The non-linearity of reinforced concrete pile sections, also considering the influence of tension-stiffening...
Article
Full-text available
The full knowledge of the morphological evolution of an historical masonry building, defined more as ‘structural aggregate’ than as ‘single construction’, together with the analysis of the architectural, structural, geological and geotechnical aspects, allow the assessment of the static safety and seismic vulnerability of the complex and the design...
Conference Paper
A Hybrid BEM-p-y curves approach was developed for the analysis of laterally loaded single piles having free or fixed head restraint conditions. The proposed method includes the non-linear behaviour of the soil by means of p-y curves, able to describe the near field soil response, located in series to an elastic half-space, that represents the far-...
Article
Full-text available
Twenty years have passed from the most recent studies about the dynamic behavior of the leaning Tower of Pisa. Significant changes have occurred in the meantime, the most important ones concerning the soil-structure interaction. From 1999 to 2001, the foundation of the monument was consolidated through under-excavation, and the "Catino" at the base...
Research
Full-text available
Computer code to evaluate the envelope of kinematic bending moments due to the pile-soil interaction during a seismic event. The kinematic analysis is preceded by a seismic ground response analysis performed with ONDA. Link to program KIN SP: http://www2.ing.unipi.it/geotecnica/08%20software.htm
Article
Full-text available
Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with the circular sections subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by c...
Conference Paper
Full-text available
The safety of buried pipeline systems is seriously threatened by earthquake hazards like seismic-induced landslides, lateral spreading due to soil liquefaction and faulting, highlighting the need to accurately evaluate their structural performance in the engineering design practice. Currently, two main finite element modelling approaches are employ...
Article
Full-text available
This paper illustrates a case history, based on full-scale tests (trial embankment). More specifically, the settlements of a full-scale trial embankment on a very compressib?e soil (organic clay) for a period of 5 years are reported. The observed settlements are compared with those obtained from an A type prediction, as well as a B type prediction....
Article
Full-text available
Climatic changes are expected to increase both the frequency and severity of flooding across the world. It is not possible to plan a continuous increase of levee height and its geometry. Therefore levees should resist to overtopping. This Technical Note gives an updated review of the surface erosion phenomena that can occur during floods and mainly...
Article
Full-text available
Understanding the structural behavior of heritage buildings is usually a very complicated task because they typically present complex deterioration and damage patterns which cannot be fully evaluated by means of visual inspections. Moreover, the reliability of such constructions largely depends on different materials, structural components and deta...
Article
Full-text available
The most recent studies about the seismic behavior of the leaning Tower of Pisa that consider the soil-foundation-structure interaction date back to twenty years ago. From 1999 to 2001, the foundation of the monument was consolidated by means of under-excavation and the "Catino" at the basement was rigidly connected to the foundation. Meanwhile, si...
Article
Full-text available
The paper deals with the interpretation of CPTu in unusual soils, such as shallow clayey layers above the water table and loose, intermediate - permeability soils (loose silt mixtures). The paper shows an approach that could be used for the first type of soil to infer the effective vertical stress from CPTu measurements and in particular from the I...
Conference Paper
Full-text available
The Medicean Aqueduct of Pisa (Tuscany, Italy), is a relevant historical infrastructure built at the end of the XVI century, composed of 954 masonry arches over a total length of 6 km. Many of the arches are affected with several decay phenomena, which occurred during the years, due to ordinary and extraordinary causes. These have changed the origi...
Conference Paper
Full-text available
Part of the information summarized in this paper has already been published (Lo Presti 2013). The context (Study Course, Subject) within which the case history has been used and the case history itself has already been described. Such details are reported for a full understanding. Anyway the present paper mainly evaluates the effectiveness of using...
Article
Full-text available
The paper illustrates an innovative method to evaluate the degree of compaction of both existing and new river embankments after their completion. A tip resistance target-profile is inferred from laboratory tests in a mini calibration chamber (CC) using a mini CPT (cone penetration test). The “laboratory” tip resistance (qcLAB) is expressed as a fu...
Book
Il manuale di Geotecnica è stato progettato e scritto per gli allievi dei corsi di studio dell’area di Ingegneria Civile e di Scienze della Terra. Tuttavia il manuale è anche concepito come strumento per l’esercizio dell’attività professionale. Il primo Tomo riguarda alcuni concetti fondamentali, l’idraulica dei terreni, i modelli di comportamento,...
Article
Full-text available
San Paolo a Ripa d'Arno is an important medieval church located in Pisa. Structural diseases, following damages by bombing during World War II, have affected the church over the last decades. After recent earthquakes the statical situation has forced the local authorities to close the church to the public. A comprehensive investigation (geophysical...
Article
Full-text available
The floodplain embankments of the Serchio River (Tuscany, Italy) have experienced several failures during their life. After the event of December 2009 a detailed geotechnical investigation has been carried out. This paper discusses the necessary criteria for a cost-effective investigation taking into account the total length of the embankments (30...
Article
A short summary is presented of the studies and the actions of Committees appointed in past 50 years for the Tower of Pisa. The discussion first addresses the attempts carried out during the whole history of the Tower to measure its movements and the efforts made to understand the origin and causes of its inclination. A history of foundation rotati...
Conference Paper
The flood plain embankments of the Serchio river have been constructed since the XVIII century and construction details are not known. These embankments have experienced failures several times during their life (last in December 2009). After the last event a detailed geotechnical investigation has been carried out. This paper discusses the necessar...
Conference Paper
Following the geotechnical characterization of 30 km long flood - plain embankments of the Serchio River (Tuscany – Italy), a number of numerical analyses have been carried out. The embankments have been constructed since the XVIII century and have experienced several failures in the years (the last in December 2009). The geotechnical characterizat...
Article
Full-text available
Sommario La ripetitività delle misure e la possibilità di indagare un volume di terreno superiore a quello corrispondente a un cam-pione in laboratorio e di ottenere registrazioni continue di parametri che mettono in luce peculiarità stratigrafiche, rendo-no le prove CPT e CPTu ideali per l'identificazione di variazioni litologiche e la ricostruzio...
Article
Full-text available
The paper shows a case study concerning the liquefaction potential assessment of deposits which mainly consist of non plastic silts and sands CF negligible). The site under study has been characterized by means of in situ tests (CPTU, SPT and DPSH), boreholes and laboratory tests on undisturbed and remolded samples. More specifically, classificatio...
Article
Full-text available
Sommario La presente nota riporta in sintesi i risultati di un confronto tra diversi metodi per la stima dell'angolo di resistenza al taglio di picco che utilizzano i ris ultati di prove SPT, ed un confronto tra i risultati di prove SPT e prove DP. Il confronto è stato effettuato a partire da una estesa banca dati messa a disposizione dalla Regione...

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