31599 - Roads, Railways and Airports Design T

Learning outcomes

Acquire good knowledge about materials and design criteria of roads, railways and airports.

Course contents

Vehicle motion and stability on road curves

Equation of motion: necessary conditions for the rolling motion to occur.

Friction, rolling and sliding motion, resistance to motion.

Vehicle Balance on curve: forces acting on a vehicle on curve; slippage, overturning and minimum radius.

 

Road design

Standards review. Road project design: fundamentals of road capacity, design flows, levels of service and cross section selection.

Road geometry:

• cartographic support choice;

• plan alignment and detection of straight stretches, circular and transition curves;

• vertical alignment: profile development, grade lines and elevation concave and convex connection;

• definition of the type sections on road embankments, cuts and side-hill, cross sections drawing and volume calculations. Works quantification and project cost estimating.

 

Functional and geometric guidelines for the construction of roads

Ministerial Decree 05/11/2001 "Functional and geometric guidelines for the construction of roads": definitions and references, road networks, road classification and compositional criteria of the carriageway, elements of the road, traffic and geometric characteristics of the sections.

Ministerial Decree 22/04/2004: Modification of Ministerial Decree 05/11/2001.

Ministerial Decree 19/04/2006 "Functional and geometric guidelines for the construction of road intersections" criteria for the location of the intersections in a road network, geometric characterization of the intersection of the elements and their functional design.

Standards for functional classification of existing roads.

 

Road embankments and cuts

Road embankments and cuts construction.

Soil compaction and quality control.

Stability analysis: calculation criteria and limit state method.

Stability improvement by pile walls with anchors: geometric and structural characteristics.

Embankments construction: light embankments with expanded sintered polystyrene, soil stabilization by hydraulic binders.

 

Characterization of road materials

Soil and aggregate mixtures: geometric characteristics, physical and mechanical properties.

Bituminous binders: penetration, softening, and thermal susceptibility tests, breaking Fraass test, ductility test, volatility test.

Bituminous emulsions.

Bituminous mixtures: general characteristics and production equipment, Marshall test, indirect tensile strength. Estimation of voids content and determination of the maximum and apparent density. Determination of the voids in bituminous specimens.

The volumetric mix design of bituminous mixtures: gyratory compactor and basics on Superpave level 1.

 

Earth pressures

Coulomb and Rankine's earth-pressure theories, methods based on a curved surface of failure.

Comparison and implications of the theories for the evaluation of the earth pressure.

Determination of earth pressure in special cases: cohesive soils, water pressure, layered soils and distributed surcharge load on the soil surface.

 

Retaining walls

Types of retaining walls: gravity, cantilever, elements walls and reinforced structures.

Retaining wall design: preliminary structural design criteria, determination of the forces applied to the structure; method of calculation and stability analysis; principles of structural analysis.

Retaining wall design in seismic areas: soil classification and seismic earth pressures.

Construction schemes and phases.

 

Road pavements

Types: flexible, rigid, composite and interlocking pavements.

Materials: asphalt concrete for wearing courses, binder and base; granular materials for subbase and cement stabilized base layers. Bituminous and hydraulic binders materials for wearing course layers:

• asphalt draining layers;

• Stone Mastix Asphalt;

• colored or printed asphalt;

• asphalt with rubber;

• cement concrete;

• grouted macadam;

• traditional and photocatalytic cement blocks.

Warm mix asphalts.

 

Road Pavements design

The concept of fatigue behavior: causes and effects.

Permanent deformation (rutting): viscous component of deformation.

Definition of equivalent standard axle (ESA) and the determination of the equivalence coefficients.

Flexible pavement: theoretical methods, semi empirical methods, rational methods and methods based on the fatigue calculation.

Rigid road pavements: semi empirical methods and rational methods.

Catalogue of pavements: design factors and catalog boards.

 

Geosynthetics

Classification, types and usage.

Characterization tests and determination of physical, mechanical, hydraulic properties and environmental aspects.

Durability of geosynthetics and partial safety factors.

Geosynthetics in road pavements: gravel roads and paved roads.

 

Structural and functional characteristics of pavements

Stratigraphic characteristics and their determination.

Structural characteristics: determination of the modules of the layers by Falling weight deflectometer (FWD) and light FWD.

Functional characteristics: definition of evenness and friction and their methods of measurement.

 

Road pavement maintenance

Optimization criteria, parameters, strategies and maintenance plan.

Maintenance interventions:

• localized recovery: topping of potholes and patches;

• sealing of cracks and joints;

• roughening of the surface without addition of material;

• roughening of the surface with the addition of material: surface treatments;

• cold (macroseal) and hot thin overlays;

• resurfacing wearing course: resurfacing or replacement.

Rehabilitation:

• partial or total rehabilitation.

 

Road safety and restraint systems

Definition of the accidents.

Data and parameters for the assessment of road safety: accident data and the degree of exposure, and risk assessment.

Directive 2006/96/EC on road infrastructure safety management: concepts VISS (assessment of impact on road safety) and RSA (Road Safety Audit).

Classifications and physical-mechanical characteristics of restraint systems.

Analysis of the regulations and criteria for the selection of restraint systems.

Performance indices: containment capacity; severity indices and working width derived from full-scale crash tests.

Transitions between different barriers and protection of singular points.

 

Tunnels

Types of underground works and key definitions.

Classification of rocks: Terzaghi's classification, Rock Quality Designation Index, Rabcewicz Pacher's Classification, Bieniawski's classification.

Excavation methods and coating techniques and related equipment.

Structural design: limit states analysis methods and methods based on soil-structure interaction. Controls during construction. Safety rules and technological systems.

 

Fundamentals of Railway engineering

The Italian and European railway networks. Railway pavement: compositional elements trucks with and without ballast. Terminology and materials: rails, fastening system, sleepers, ballast, sub-ballast and subgrade. Rail devices, exchanges or switches, and the long welded rail. Stations: location and typologies. Railway maintenance: tamping, leveling and alignment.

 

Fundamentals of Airport Engineering

Classification criteria.

Definitions and geometric characteristics of the elements of the airport: taxiways, parking areas, runways, etc. Choice of airport location, airport servitudes and factors that influence the orientation of the runways.

Rigid and flexible airport pavements: materials, loads analysis, concept of Landing Gear Loading and design criteria according with the FAA method. Influence of expansion, contraction and construction joints for rigid pavements.

Readings/Bibliography

COSTRUZIONI STRADALI - ASPETTI PROGETTUALI E COSTRUTTIVI - Ed. HOEPLI - Giulio Dondi, Andrea Simone, Valeria Vignali, Claudio Lantieri

Teaching methods

Lessons and team (2-3 students) works. A digital terrain model is assigned and the students design a small road project, also by CAD (no road drawing plugins). Print copies aren't required, students can deliver a CD.

Assessment methods

Oral examination

Teaching tools

Digital projector. Demonstrations in the LAS laboratory (Laboratory of Roads DICAM), showing the test equipments described in the lectures.

Office hours

See the website of Giulio Dondi