The course aims to provide knowledge on the static and dynamic behavior of shallow foundations, pile foundations and mixed foundations, for a complete geotechnical design of the different types of foundation both in SLE and SLU conditions. The main in situ tests for the preliminary and indispensable static and dynamic geotechnical characterization of the foundation ground are also presented. Finally, the fundamental criteria for the structural design of these elements are briefly discussed.
The course's methodology includes frontal lessons, written classroom exercises (one of which is mandatory and regards the geotechnical design of a shallow foundation) and the writing of a technical report on the geotechnical design of a pile foundation.
Lastly, a technical visit is planned in Sicily, in order to increase the student's knowledge of the topics discussed in the classroom and to bring the student closer to the world of work and practice.
Frontal lessons through Power Point presentations. Seminars in collaboration with geotechnical company and/or engineers. Exercises in the classroom. Design of a pile foundation to be carried out individually and reviewed by the teacher.
1. GEOTECHNICAL INVESTIGATIONS: Introduction: Extension of investigations, purpose of investigations, programming of investigations. Surveys and sampling: accessible excavations, percussion drilling, rotating surveys, sampling, sampler characteristics. In-situ tests: CPT and CPTU tests, SPT tests, vane tests, static and dynamic Dilatometer tests, pressure tests, SASW, MASW, monitoring of foundation settlements. Empirical correlations: main empirical correlations between the results of in-situ tests and geotechnical parameters. (Reference texts: 1, 4, 5).
2. SHALLOW FOUNDATIONS: Types of foundations: Introduction (definition of shallow foundation, choice of laying plan, partially or totally compensated shallow foundations, new foundations for existing buildings). Foundations on plinth (isolated or with connecting beams). Foundations on beams or raft. Bearing capacity of soil-foundation systems: Failure mechanisms (general failure, local failure, puncting failure). Simplified scheme (factors affecting bearing capacity and depth of the failure surface). Methods for calculating the bearing capacity: Prandtl Solution (1921), Terzaghi solution (1943), Brinch-Hansen solution (1970) for incoherent and coesive soil, Richard et al. solution (1993), Paolucci and Pecker solution (1997). Formulations for non-general failure mechanisms. The bearing capacity for foundations on stratified soil. Methods for calculating earth-induced stresses. Settlements: Introduction (absolute settlements, differential settlements, rigid rotation, relative rotation, angular deformations, inflection, curvature, effects of foundation settlements on structures, depth of Influence for the evaluation of foundation settlements). Calculation Methods for non-cohesive soils (Theory of Elasticity, Burland and Burbidge Method (1985), Schmertmann Method (1970), Berardi and Lancellotta Method (1991). Calculation Methods for cohesive soils: the elastic settlement and the primary consolidation settlement according to the Skempton and Bjerrum Method (1957); secondary consolidation settlements. Settlements due to seismic events or vibro-pile constructions; settlements due to excavations. Allowable settlements (geotechnical literature, Guidelines of EC1 and EC7, Italian technical regulations, methods to reduce distortions in foundation). Italian and European technical regulations for geotechnical design of shallow foundations. Main aspects of structural design of shallow foundations. (Reference texts: 2, 4, 5).
3. PILE FOUNDATIONS: Vertical loaded piles: Execution types. Limit load (lateral resistance, end resistance, correlation with in-situ test results, dynamic formulas). Settlements (Poulos method (Poulos & Davis, 1980), simplified nonlinear model, pile for settlement reduction). Pile group (bound effect, group effect, bearing capacity and settlements of a pile group). Negative friction (physical phenomena, modeling). Vertical load tests and non-destructive testing (test equipment, execution mode, instrumentation, interpretation of results; non destructive controls). Piles subject to horizontal forces: General considerations. Failure mechanisms and limit “load” (Broms method, 1964). SLE (Matlock and Reese method, 1960; transfer functions’ method). Horizontal load tests (test equipment, execution mode, instrumentation, interpretation of results). Passive piles (elastic-nonlinear and rigid-plastic approaches). Mixed foundations. Italian and European regulations for geotechnical design of pile foundations and mixed foundations (D.M. 14/01/2008, EC7, 2004, EC8, 2004). Notes on the structural design of pile foundations and mixed foundations (Reference texts: 3, 4, 5).
4. SOIL-STRUCTURE INTERACTION: Soil-foundation interaction: General (Eurocode 7, Eurocode 8, Italian law, formation of plastic hinges, choice of building ground model). Shallow foundations (static conditions: Winkler method. Dynamic conditions: shaking table tests, Gazetas method, 1991, numerical modeling). Pile foundations (kinematic interaction and inertial interaction, pseudo-static analysis, dynamic analysis, numerical modeling). Soil-foundation-superstructure interaction: General (factors to consider, shaking table tests). Shallow foundations (limit situation method, equivalent stiffness method, Gazetas approach, numerical modeling). Pile foundations (soil-pile-raft- superstructure interaction). (Reference texts: 4, 5).
1. R. Lancellotta: “Geotecnica”, Quarta Edizione, Zanichelli, Bologna 2012.
2. R. Lancellotta, J. Calavera: "Fondazioni", McGraw-Hill, Milano 2016.
3. M.G. Poulos, E.H. Davis: “Analisi e progettazione di fondazioni su pali”, Flaccovio
Editore, Seconda ristampa, 2005.
4. C. Viggiani: “Fondazioni”, Hevelius, Napoli 1999.
5. R. Lancellotta, Costanzo D., Foti S. "Progettazione geotecnica", Hoepli, 2011.
6. Scientific papers and other materials will be given to the students by means of the "Studium" system of the Catania University website.