CONSTRUCTION OF ROADS
cod. 06352

Academic year 2007/08
3° year of course - First semester
Professor
Academic discipline
Strade, ferrovie e aeroporti (ICAR/04)
Field
Ingegneria civile
Type of training activity
Characterising
81 hours
of face-to-face activities
9 credits
hub:
course unit
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Learning objectives

he course aims to give the basis for the geometric design of road structures and the choice of materials an realization of road construction.

Prerequisites

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Course unit content

1) ROADS AND VEHICLE.<br />Resistances to motion.<br />Locomotion mechanic and general equation for traction.<br />Friction: coefficient of friction fa. Lamm-Herring relationship.<br />Stopping sight distance.<br />Overtaking sight distance.<br />Road vehicles performances.<br />Perception of road environment.<br /><br />2) ROAD DESIGN IN HORIZONTAL PLAN.<br />Design speed. <br />Road axis.<br />Horizontal plan.<br />Vehicle stability on curve.<br />Visibility in curve.<br />Superelevation in curve: maximum transversal friction criterion, maximum transversal gradient criterion, proportionality criterion.<br />Definition of Nomogramma of CNR (curvilinear method).<br />Calculation of horizontal radius by mean of optical criteria: horizontal sight distance along the inside of a curve.<br />Stopping sight distance and passing sight distance.<br />Spiral (transition curve): intrinsic equation, Cartesian coordinates equation: Fresnel integrals, series expansions.<br />Analytical calculation of shifting R. <br />Geometric formula of parameter A, unitary spiral, minimum value of parameter A: dynamic criterion, constructive criterion, optic criterion. <br />Spiral insertion in road axis: straight-curve (preserved radius, preserved centre, preserved vertex). Flex spiral, continuity spiral: rigorous calculation and approximated relationships (Osterloch abacum).<br />Composition of horizontal axis.<br />Asymmetrical spirals (CNR).<br /><br />3) vertical alignment of road.<br />Maximum grade of vertical alignment.<br />Vertical circular and parabolic curves.<br />Horizontal and vertical coordination.<br /><br />4) ROAD CROSS SECTION.<br />Road cross section according to CNR.<br />Characteristics of road cross section.<br />Particular road cross section.<br />Road cross section in curve.<br />Curve enlargement. <br />Variation of road cross section in curve.<br />Definition of relative minimum slope “i”.<br /><br />6) Road structure construction.<br />Definition of soils as material for embankments.<br />Embankment.<br />Excavation.<br />Subgrade. <br /><br />7) Elements of road geotechnics.<br />Fundamental parameters of soils: grading analysis, compressibility, shear strength.Water susceptivity, Atterberg limits: LL, LP, LR, IP.<br />Soils classification: Index group, HRB, FAA. Soils compaction. Soils compaction in (s,W) chart. Proctor and AASHTO test. Control of in situ density.<br />Soils correction. <br />Embankments construction and plant equipments. Subgrade load bearing capacity. Load bearing capacity test: plate, repeated cycles, McLeod relationship, CBR test, CBR Index. Definition of CBR in situ. Compressibility modulus M. <br />Subgrade water protection. Ice action in road embankments.<br /><br />8) Stone aggregates.<br />Classification of stone aggregates. Required characteristics. Shape characteristics. Test on aggregates: grading analysis, Deval, microdeval, Los Angeles, dynamic crushing , CPA, sand equivalent, ice susceptivity. Aggregate characteristic referred to its employment: subbase, base, binder, wearing course. Sand and filler characteristics. <br /><br />9) BINDERS.<br />Binders: bitumen, coal tar, asphalt. Organic binders with polymers, oxidized bitumen, cut-back asphalt, bituminous emulsions. Controls on bituminous binders: penetration, ring and ball temperature, Frass temperature, viscosity. Heukelom abaci. Thermal susceptivity. Stiffness modulus. Bitumen-aggregate adhesion. <br /><br />10) MIXTURES FOR ROAD STRUCTURES.<br />Mechanical characteristics of mixtures. Granular mixes subbase. Soil stabilisation for subbase. Bounded and non-bounded for base layers. Bituminous mixtures. Design of optimum grading curve: Fuller curve and grading distribution. Percentage of filler. Determination of binder percentage: English method (voids method), French method (specific surface or Duriez).<br />Stability of bituminous mixture: Marshall test.<br />Determination of bitumen percentage by mean of Marshall method.<br />Mixture manufacturing. Transportation and realization. Bituminous mixture aging.<br />Controls during realization and service life.<br />Modified bituminous mixtures dense graded and porous, grave emulsion, slurry seal.<br /><br />11) ROAD PAVEMENTS DESIGN <br />Traffic loads: coefficient of axis equivalence, vehicle speed. Types of road pavements: flexible, rigid and semi-rigid.<br /><br />Mechanical characteristics of layers: subgrade, subbase, base, binder and bituminous wearing course, cement concrete pavements. Environmental conditions influence. Pavement design. Empirical design: AASHO, Interim Guide, Road Note 29. Rational design for pavement design: stress-strain analysis, fatigue calculation, rutting calculation. Design catalogs.

Full programme

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Bibliography

P. FERRARI, F. GIannINI: "Geometria e progetto di strade", Vol. I, ISEDI. <br />P. FERRARI, F. GIannINI: "Corpo stradale e pavimentazione ", Vol. II, ISEDI. <br />G. TESORIERE: "Strade ferrovie e aeroporti: il progetto e le opere d'arte", Vol. I, UTET. <br />G. TESORIERE: "Strade ferrovie e aeroporti : opere in terra e soprastrutture", Vol. II, UTET. <br />F. GIannINI, F. LA CAMERA, A. MARCHIONNA: "Appunti di costruzione di strade ferrovie ed aeroporti", ESA.

Teaching methods

Oral examination about course subjects and exercise. Road Design: type F1 DM 5/11/2001.

Assessment methods and criteria

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Other information

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