Stefano Stacul

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

The paper shows the geotechnical characterization of a soft clay test site by means of laboratory testing. Such a test site was established in the campus of the Department of Biology of the University of Pisa at about 1.6 km from the Leaning Tower square. The main (but not exhaustive) scope of the present research activity was to compare the propag...

The kinematic bending and filtering potential of a fixed-head pile are explored when large shear strains are generated in the surrounding soil during the passage of seismic waves. The problem is treated numerically by employing a freely available 1D code to derive soil response at free-field conditions and an advanced 3D finite-difference (FD) mode...

Seismic response analyses

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...

This paper shows and compares the experimental results obtained by using a standard cone (10 cm 2) and a mini piezocone (2 cm 2). Tests were carried out at Calendasco (Piacenza, Italy) in a natural soil deposit mainly consisting of clayey-sandy silts. Grain size distribution with depth was also available. Other tests were carried out at Cavezzo (Mo...

This paper describes the implementation and use of a mechanical cone penetration test (CPTm) database for the evaluation of the liquefaction potential in some areas of Tuscany. More specifically, the database contains 4500 CPTm covering an area of 1787 square km and mainly concerns some coastal areas of Tuscany. Available simplified liquefaction ev...

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...

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...

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...

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...

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...

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...

The world energy politics affects civil engineering as well as all other sectors. Especially, minimum energy consumption and the use of renewable energy are gaining popularity. In accordance with this objective, design and application of civil engineering is also continuously developing. Just as the world, the implementation of civil engineering sh...

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...

The present work aimed to validate a low-cost passive monitoring procedure. For its validation, the monitoring of atmospheric organic pollutants - polycyclic aromatic hydrocarbons (PAH) was carried out in a capital of the central-western region of Brazil. The sensors were fixed on poles intended for electrification during the dry season. After 15 d...

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...

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...

CPT-based simplified methods are the common used approaches to determine the liquefaction hazard and they require cone penetration test with electrical tip. However, in some countries, as Italy, penetrometric tests are carried out with mechanical tip (CPTm). The cone-shape effects on sleeve friction (fs) have the greatest influence on soil classifi...

The most known methods for liquefaction hazard assessment are simplified empirical procedures (Liquefaction Evaluation Procedures-LEPs), which require cone penetration test with electrical tip or the measure of u (CPTu). However, in most countries, as Italy, penetrometric tests are carried out with mechanical tip (CPTm). The cone-shape effects on s...

It is well known that there are only few experimental evidences and analysis methods for piled raft foundations subjected to lateral loads. On the contrary, a lot of studies are focused on piled rafts under vertical loads and it was seen how more rational design methods can led to great benefits in terms of performance and in saving of construction...

This paper shows the results of free-field seismic response analyses (SRA), that were performed for the subsoil conditions of Piazza dei Miracoli in Pisa. The site investigation and in particular the shear wave velocity profile is extended down to 120 m below the ground level. One-dimensional SRA were carried out by using three computer codes, EERA...

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...

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...

Interpretive software for CPT, CPTu, SCPTu tests (cone penetration test data interpretation, seismic cone data analysis, pile bearing capacity module, shallow foundation settlement module, dissipation test module, assessment of liquefaction potential index). CPT PaGE: http://www2.ing.unipi.it/geotecnica/08%20software.htm

A proper assessment of the soil effective stress state is crucial in many cases to identify a potential geological/geotechnical hazard as shallow landslides or failure of levees that may have a significant impact on human activities and development. This paper is aimed at validating a methodology for the expeditious and economic determination of ef...

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...

Seismic tests consist in the measurement of propagation velocity of body or surface waves into the subsoil or at the contact soil/air or soil/water. Surface waves are dispersive by nature and propagate along the contact surface of two media having very different properties. Surface waves velocities can be measured at ground surface or at the sea fl...

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-...

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

Computer code to perform seismic ground response analyses of soil deposits in time domain (analysis types: linear and non-linear). Link to program ONDA 1.4: http://www2.ing.unipi.it/geotecnica/08%20software.htm

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...

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,...

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...