Optimum rigid pavement design by genetic algorithms M.N.S. Hadi a, * , Y. Ar®adi b a Faculty of Engineering, Department of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia b Department of Civil Engineering, Faculty of Engineering ± Atma Jaya, Yogyakarta University, Jalan Babarsari 44, P.O. Box 1086, Yogyakarta 55281, Indonesia Received 1 November 1999; accepted 22 February 2001 Abstract The design of rigid pavements according to AUSTROADS involves assuming a pavement structure then using a number of tables and ®gures to calculate the two governing design criteria, the ¯exural fatigue of the concrete base and the erosion of the sub-grade/sub-base. Each of these two criteria needs to be less than 100%. The designer needs to ensure that both criteria are near 100% so that safe and economical designs are achieved. This paper presents a for- mulation for the problem of optimum rigid road pavement design by de®ning the objective function, which is the total cost of pavement materials, and all the constraints that in¯uence the design. A genetic algorithm is used to ®nd the optimum design. The results obtained from the genetic algorithm are compared with results obtained from a Newton± Raphson based optimisation solver. The latter being developed using spreadsheets. Ó 2001 Civil-Comp Ltd. and Elsevier Science Ltd. All rights reserved. Keywords: Optimum design; Rigid pavements 1. Introduction The initial cost of building rigid pavements is rela- tively higher than that involved in constructing ¯exible pavements. However, the overall cost of building and maintaining ¯exible pavements outweighs those of rigid pavements. In 1996, DECICORP [1] were commissioned by the Steel Reinforcement Institute of Australia, SRIA to study the factors that in¯uence the design and con- struction of rigid pavements. They studied the cost of construction of a 38 km 8-lane road, i.e. 304 lane km. The assumed design life of the pavement was 40 years, 1998±2037 being built on a three CBR sub-grade. Five types of pavement construction were considered, con- tinuously reinforced concrete pavement, plain concrete pavement, full depth asphalt with an asphalt overlay, cement treated base and asphalt overlay, and granular overlay with an asphalt riding course. DECICORP conducted a cost analysis for all types of pavements including the initial construction cost and the cost of maintenance during the life of the pavement, this in- cluded the disruption to the trac during maintenance periods. The comparison revealed that continuously reinforced concrete pavement option had the lowest overall cost, including both initial construction and continuing maintenance costs. DECICORP's [1] report concludes that it is cheaper to build rigid pavements that require less maintenance and provide pavements with longer life spans. These pavements prove to be more economical in the long run. This economical advantage coupled with the fact that rigid pavements provide higher strengths thus being able to carry higher trac loadings. Rigid pavements have been used all over the world for several decades and dierent road authorities and organisations have developed design methods that suit their locale. To name a few, the American Associ- ation of State Highway and Transportation Ocials AASHTO), the Portland Cement Association PCA), Computers and Structures 79 2001) 1617±1624 www.elsevier.com/locate/compstruc * Corresponding author. Tel.: +61-2-4221-4762; fax: +61-2- 4221-3238. E-mail address: [email protected] M.N.S. Hadi). 0045-7949/01/$ - see front matter Ó 2001 Civil-Comp Ltd. and Elsevier Science Ltd. All rights reserved. PII:S0045-794901)00038-4
Optimum rigid pavement design by genetic algorithms
Jun 28, 2023
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