Effects of ‘road friendly’ suspensions on long-term flexible pavement performance

Abstract

This paper examines the effects of ‘road friendly’ heavy goods vehicle suspensions on long-term flexible pavement performance. A deterministic ‘whole-life pavement performance model’ (WLPPM) is used to calculate pavement damage due to realistic traffic and environmental loading. The traffic is modelled first as a fleet of steel-sprung heavy goods vehicles and second as a fleet of ‘road friendly’ air-suspended vehicles. The pavement life predictions are compared for the two cases and with results from a simple road damage analysis based on the ‘fourth power law’. It is concluded that changing to a fleet of ‘road friendly’ vehicles would not significantly affect the life or maintenance costs of thicker asphalt pavements (motorways and trunk roads) where the mode of failure is permanent deformation (rutting). However, the life of thinner pavements (minor roads) that fail by fatigue damage and pot-holing would be increased significantly if the vehicle fleet changed to road friendly suspensions. Predictions from the simplified fourth power law approach tend to significantly overestimate the benefits of road friendly suspensions for major road conditions compared to the WLPPM predictions. It is concluded that the potential economic benefits in England and Wales of converting to air suspensions may be only 30 per cent of those predicted by the authors of the EC ‘road friendly suspensions’ regulations.

Keywords

road damage flexible pavement long-term pavement performance heavy vehicles road friendly suspensions air suspension leaf spring suspension

Get full access to this article

View all access options for this article.

References

Cebon

Interaction between heavy vehicles and roads. SAE SP-951, 930001, 1993.

Anon. Dynamic Loading of Pavements, Road Transport Research, 1992 (OECD, Paris).

Eisenmann

Dynamic wheel load fluctuations-road stress. Strasse und Autobahn, 1975, 4, 127–128.

Anon. The AASHO road test, Report 5, Pavement Research. Highway Research Board, Special report 61E, 1962.

Sweatman

P. F.

A study of dynamic wheel forces in axle group suspensions of heavy vehicles. Australian Road Research Board, Special report SR27, 1983.

Mitchell

C. G. B.

Gyenes

Dynamic pavement loads measured for a variety of truck suspensions. In Second International Conference on Heavy Vehicle Weights and Dimensions, Kelowna, British Columbia, 1989.

Berry

Proposal for a Council Directive, COM(90) 486, 1990 (Commission of the European Communities, Brussels).

Anon. Council Directive 92/7/EEC, 1992 (The Council of the European Communities).

Kinder

D. F.

Lay

M. G.

Review of the fourth power law. ARRB, Internal report AIR000-248, 1988.

10.

Magnusson

Carlsson

H. E.

Ohlsson

The influence of heavy vehicles' springing characteristics and tyre equipment on the deterioration of the road. VTI (translated by TRRL as WP/V&ED/86/16, 1986), Report 270, 1984.

11.

Collop

A. C.

Cebon

A model of whole-life flexible pavement performance. Proc. Instn Mech. Engrs, Part C, 1995, 209(C6), 389–408.

12.

Hardy

M. S. A.

Cebon

Response of continuous pavements to moving dynamic loads. ASCE J. Engng Mechanics, 1993, 119(9), 1762–1780.

13.

Collop

A. C.

Cebon

Hardy

M. S. A.

A viscoelastic approach to rutting in flexible pavements. ASCE J. Transpn Engng, 1995, 121(1), 82–93.

14.

Collop

A. C.

Cebon

Stiffness reductions of flexible pavements due to cumulative fatigue damage. ASCE J. Transpn Engng, March-April 1996, 122(2), 131–139.

15.

Anon. National speed survey 1987. Department of Transport, Statistics Bulletin (88)30, 1988.

16.

Cole

D. J.

Cebon

Truck suspension design to minimise road damage. Proc. Instn Mech. Engrs, Part D, 1996, 210(D2), 95–107.

17.

Croney

Is the measured deflection of a flexible pavement a reliable guide to life prediction and overlay design. Highways, 1990, 58(Part 1968), 24–26.

18.

Kennedy

C. K.

Fevre

Clarke

C. S.

Pavement deflection: Equipment for measurement in the United Kingdom. Transport and Road Research Laboratory, TRRL laboratory report 834, 1978.

19.

Chua

K. H.

Der Kiureghian

Monismith

C. L.

Stochastic model for pavement design. ASCE J. Transpn Engng, 1992, 118(6), 769–786.

20.

Cooper

K. E.

Pell

P. S.

The effect of mix variables on the fatigue strength of bituminous materials. TRRL laboratory report 633, 1974.

21.

Gillespie

T. D.

Effects of heavy vehicle characteristics on pavement response and performance. Transportation Research Board, NCHRP report 353, 1993.

22.

Brown

S. F.

Brunton

J. M.

Improvements to pavement subgrade strain criterion. ASCE J. Transpn Engng, 1984, 110(6), 551–567.

23.

Hardy

M. S. A.

The response of flexible pavements to dynamic tyre forces. PhD thesis, Cambridge University Engineering Department, 1990.

24.

Peattie

K.R.

Flexible pavement design. In Developments in Highway Pavement Engineering, Vol. 1 (Ed. Pell

P. S.

), 1978, Ch. 1 (Applied Science Publishers, London).

25.

Anon. Highways and Transportation Statistics, 1995/96 Estimates and 1993/94 Actuals, 1995, The Chartered Institute of Public Finance and Accountancy, Statistical Information Service, 14.95, ISSN 0964-5624.

26.

Brown

S. F.

Brunton

J. M.

Stock

A. F.

The analytical design of bituminous pavements. Proc. ICE, 1985, 79, 1–31.

27.

Sayers

M. W.

Gillespie

T. D.

Paterson

W. D. O.

Guidelines for conducting and calibrating road roughness measurements. World Bank technical paper 46, 1986.

28.

Anon. Design Manual for Roads and Bridges, Vol. 7, Pavement Design and Maintenance, 1994 (Department of Transport, UK).