A new approach has been developed for determining layered elastic moduli from in situ load-deflection data. This approach is called forwardcalculation, and it differs from backcalculation in that modulus values are calculated directly from the load-deflection data by using closed-form formulas rather than through iteration. The closed-form equations are used for the subgrade and the bound surface course for both flexible and rigid pavement systems. Intermediate-layer moduli are estimated through commonly used modular ratios between adjacent layers. The entire pre-1998 Long-Term Pavement Performance (LTPP) set of backcalculated results was screened with forwardcalculated moduli. Because both back-and forwardcalculation techniques use identical falling weight deflectometer load-deflection data as input, it was expected that the moduli derived from each approach should be reasonably close to each other. This result was not always the case, however. Forwardcalculated values were, in most cases, more stable on a section-by-section basis than the backcalculated values in the LTPP database. Similarly, the forwardcalculated values usually appeared more reasonable. The exception to this finding was the portion of the database based on slab-on-dense-liquid or slab-on-elastic-solid theory, in which the correspondence between the two approaches was excellent, and both approaches were stable.


    Access

    Download

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Forwardcalculation of Pavement Moduli with Load-Deflection Data


    Additional title:

    Transportation Research Record: Journal of the Transportation Research Board


    Contributors:


    Publication date :

    2007-01-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




    Integrating Seismic and Deflection Methods to Estimate Pavement Moduli

    Abdallah, Imad / Yuan, Deren / Nazarian, Soheil | Transportation Research Record | 2001



    Dynamic Analysis-Based Approach To Determine Flexible Pavement Layer Moduli Using Deflection Basin Parameters

    Lee, Yung-Chien / Kim, Y. Richard / Ranjithan, S. Ranji | Transportation Research Record | 1998