STP1198: Backcalculation of Pavement Layer Moduli, Thickness and Stiff Layer Depth Using a Modified Newton Method

    Harichandran, RS
    Associate Professor, Michigan State University, East Lansing, MI

    Mahmood, T
    Graduate Student, Michigan State University, East Lansing, MI

    Raab, AR
    Senior Staff Officer, Washington, DC

    Baladi, GY
    Professor, Michigan State University, East Lansing, MI

    Pages: 15    Published: Jan 1994


    Abstract

    A modified Newton method for the backcalculation of pavement layer moduli, thicknesses, and stiff layer depth from measured surface deflections is presented. The method is an iterative one and can use any mechanistic analysis program for forward calculations (presently an extended precision CHEVRON program is used for this purpose). This method has been implemented in a new backcalculation program named MICHBACK. Several examples of backcalculation based on theoretical deflection basins generated by the extended precision CHEVRON program are presented, and the effect of errors in input layer thicknesses and stiff layer depth on the backcalculated moduli are studied. Moduli backcalculated by MICHBACK are compared with results obtained by the EVERCALC 3.0 and MODULUS 4.0 programs.

    Keywords:

    backcalculation, pavement evaluation, elastic layer, Newton method, gradient method, stiff layer, MICHBACK, EVERCALC, MODULUS


    Paper ID: STP18142S

    Committee/Subcommittee: D04.39

    DOI: 10.1520/STP18142S


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