72771 - Road Infrastructure Advanced Design M

Learning outcomes

With the achievement of the training credits, the student has the specialized knowledge on the geometric components and on the legislation for the design of roads. He is able to organize an infrastructural project also with the help of dedicated programs and to independently face the project of the main structural elements (paving, earth constructions, support works) and safety devices. He knows the methodologies for sizing airport floors and the specialized design elements of railway superstructures.

Course contents

The road project

Composition of a road project at the preliminary, final and executive levels. Assisted geometric design: definition and characteristics of the digital terrain model (DTM) on a raster and vector basis. Design by means of polygonal axis and by elements. Illustration of the characteristics of the main road design tools. Speed diagram, visibility distances, characteristics of the planimetric junctions. Plano-altimetric coordination of the route and Lamm criteria.

Construction of embankments and trenches

Stability of the laying surface: breaking and plasticization loads; immediate and deferred settlements. Slope stability: discretization and verification techniques, comparative analysis of the Fellenius and Bishop methods, determination of stability improvement by means of tie rods and verification of anchors. Consolidation of laying surfaces and embankments. Thickening problems: sampling techniques and Proctor and C.B.R.

The road foundations.

Definition of strength; load test with plate (PLT): single cycle and repeated cycles, definition of the compaction coefficient; HRB method. CBR and FAA method. Determination of K , Md and E.

Use of Geosynthetics

General information on geosynthetics: woven and non-woven geotextiles, geogrids, geonets, geocomposites, geocells, geomembranes. Functions and applications of geosynthetics: separation, reinforcement, filtration, drainage, surface reinforcement and waterproofing. Physico-chemical characteristics of the main geosynthetics and polymers; creep and apparent creep, durability and method of partial safety factors. Practical recognition of the main geosynthetics. Acceptance and characterization tests.

Special techniques

Lightened embankments for compressible soils: use of expanded clay, sintered expanded polystyrene (EPS) Pre-consolidation techniques with vertical drains (belt drains) for deferred settlements; Secondary raw materials: reuse of waste materials: ROSE, fly ash and blast furnace slags. Earth stabilization with hydraulic binders: binary and ternary mixtures.

Road superstructures

Superpave: the SHRP-SUPERPAVE method for the mix design of bituminous conglomerates with a giratory compactor. Tests on binders: RTFOT, pressure aging vessel, rotational viscometer, bending beam rehometer, DSR and DTT. Rheology of bituminous conglomerates: dynamic tests, creep tests, complex modulus, influence of temperature and frequency.

Calculation methods. Fatigue calculation of flexible road superstructures. Identification of the useful design life of the superstructure: traffic measurements, design traffic composition, vehicle equivalence factors, identification of traffic in ESA (equivalent standard axle). Semiempirical methods :, Road Note 29, AASHO (PSI, IS), calculation examples. Rational methods: Bisar, fatigue laws, calculation examples. Road superstructures catalogs. Cementitious floors: Westergaard, Burmister-Peltier, Hogg. Influence of temperature: seasonal variations, daily variations.

Control techniques: falling weight deflectometer, Benkelman beam.

Traditional works. Thrust of lands in a rigid-plastic regime: Rankine, Columb, Muller-Breslau. Boundary conditions: top surface geometry and structure-ground friction, NAV-FAC project graphics. Traditional works: walls in concrete in particular conditions: stratified back ground, presence of hydraulic head. Walls in seismic areas: Mononobe-Okabe methods and Italian legislation (D.M. 16-1-1996).

Special works. Thrust of lands in an elastic-plastic regime and soil-structure interaction: influence of soil OCR and depth according to Janbu on the coefficient. (kj) of land thrust. Special works: multi-level berliners.

Reinforced walls

Characteristics of reinforced soils. Definitions of macro-reinforcement and micro-reinforcement. Calculation criteria: verification of external and internal stability, active and passive wedge, limit height, minimum length of the reinforcements. Application examples: "wrap-around" technique, Textomur. Methods of implementation

Tunnels

Fields of use. Geometric and structural characteristics: box-shaped, launch pad, thrust wall. Calculation criteria: thrust during launch and operation.

Preliminary investigations: seismic refraction, cross-hole, down-hole, core drilling from the surface and from the face of the excavation, pilot tunnel. The excavation techniques. Determination of the ground thrust: arc effect theory according to terzaghi, rock mass classification according to Bieniawski and rock mass rating (RMR) method. Coatings: temporary and definitive coatings.

Road safety

Characteristics of the national road network, classification and geometric characteristics of the roads. Accidents: causes and European policies for road safety. Factors affecting road safety: grip and regularity. Road management systems: the road cadastre, establishment, management and updating. GPS in the constitution of the road cadastre.

High performance pavements

Draining and sound-absorbing bituminous conglomerates. Antiskid bituminous mixtures. Splitmastixasphalt.

Safety barriers

Evolution of the Italian and European legislation. Barrier classification criteria. Containment Levels and Severity Indices. Acceptance limits: ASI, THIV, and PHD parameters. Positioning and anchoring criteria. Crash tests.

Readings/Bibliography

§ Dondi G., Lantieri C., Simone A., Vignali V. 2013. Costruzioni stradali - Aspetti progettuali e costruttivi Monografia / trattato scientifico in forma di libro – 2013, ISBN – 9788820352592. 443 pag. Hoepli Ed.Milano

§ G. TESORIERE, Costruzioni di Strade, Ferrovie ed Aeroporti.

§ F. GIANNINI e P. FERRARI, Costruzioni stradali e ferroviarie.

§ A. GOMES CORREIA, Flexible Pavements , Balkema, 1996, ISBN 90 5410 523 2

Teaching methods

Theoretical lessons will be integrated with practical group exercises.


Exercises.


The exercises consist in the design, assisted by computer, of the geometric part of a road section or a road intersection

Assessment methods

The final oral exam will be structured in order to verify the degree of in-depth study achieved in the following 3 main areas of the course:

- advanced design and maintenance of road pavements

- design of structural works for the construction of road infrastructures

- safety analysis of intersections and road layouts in urban and extra-urban areas

Teaching tools

All students are provided with lecture note

Office hours

See the website of Andrea Simone

See the website of Margherita Pazzini