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Civil-Comp Proceedings
ISSN 1759-3433 CCP: 77
PROCEEDINGS OF THE NINTH INTERNATIONAL CONFERENCE ON CIVIL AND STRUCTURAL ENGINEERING COMPUTING Edited by: B.H.V. Topping
Paper 26
A Design Chart for the Design of Flexible Pavements Based on Finite Elements B.C. Bodhinayake and M.N.S. Hadi
Faculty of Engineering, University of Wollongong, Australia Full Bibliographic Reference for this paper
B.C. Bodhinayake, M.N.S. Hadi, "A Design Chart for the Design of Flexible Pavements Based on Finite Elements", in B.H.V. Topping, (Editor), "Proceedings of the Ninth International Conference on Civil and Structural Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 26, 2003. doi:10.4203/ccp.77.26
Keywords: pavement analysis, flexible pavement, finite element, cyclic loading, nonlinear, ABAQUS, permanent strain, rut depth, design chart.
Summary
Presently used mechanistic methods in the analysis of layered pavement systems
employ either multi-layer elastic theory or finite element theory. Various computer
programs have been developed as tools for those methods. In most mechanistic
methods, the pavement layers are considered as homogeneous, isotropic and linear
elastic, and the loading is considered as static. However, few programs have been
developed to incorporate nonlinear, and/or anisotropic materials, dynamic or cyclic
loading and the particulate structure of granular materials. These computer programs
are very useful for pavement engineers who design pavements for complex loading
situations with modified materials, whereas those who design pavements for
standard loading conditions with specified materials would not necessarily use such
complex methods. To make the design procedure easier, a research is being
undertaken to develop a design chart for the design of flexible pavements. In
developing this design chart, output results from a finite element computer code
ABAQUS/Standard [1] is used, while the pavement structure is modelled as a finite
element model, materials are modelled as linear elastic and nonlinear and the
loading is considered as cyclic loading in the input data to the computer code.
A pavement structure with a thin bituminous surfacing, a granular base and a
subgrade is modelled as a finite element model. Half of standard axle is considered
in the current analysis. The pavement structure is assumed to be a three metre cube.
Due to symmetry of the pavement structure only quarter of the cube is considered.
The 40 kN load in half of standard axle is transferred to the road pavement through
dual wheels inflated to a pressure of 750 kPa [2]. The contact area between tyre and
pavement surface is assumed as a rectangle as suggested by Huang [3], having an
area of 0.5227L2 and a width of 0.6L.
The developed isotropic hardening curve, and the relationships used between strain and number of load applications are verified by carrying out the analysis for a pavement structure where ALF (Accelerated Loading Facility) trials have been carried out [7]. The displacements (rut depths) versus number of load applications plotted with calculated values and field values are found to be in agreement. References
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