by McCracken, Jennifer Kay

Abstract (Summary)
A new pavement design procedure, known as the Mechanistic-Empirical Design Guide (MEPDG), is in development and incorporates new mechanistic-based models and performance prediction models. Structural response models are used to compute critical stresses, strains, and displacements in pavement systems due to traffic loads and climatic factors. These responses of the pavement structure are determined using finite element. Therefore, the MEPDG developed neural networks to reduce the necessary computational time. It is essential that the finite element models accurately depict the response of the slab to insure that calculated stress is representative of actual pavement stresses. Therefore, the focus of this study will be to develop finite element models that will be validated/calibrated from actual field strain measurements. The following study analyzes the response of a joint plain concrete pavement (JPCP) to an applied load. The response of the pavement is characterized by performing seasonal load testing on an instrumented JPCP. The load testing consists of traversing trucks with known axle loads and configurations across the pavement and performing falling weight deflectometer (FWD) testing. The effects of varying restraint conditions, temperature and moisture gradients, and load magnitudes on the measured deflections and strains are characterized. These measured deflections and strains are also used in the development and validation/calibration of finite element models. It was determined that temperature gradients at the time of FWD testing have an impact on load transfer efficiency, measured deflections, and the magnitude of the Void parameter, as well as the measured strain. An analysis of measured strains indicated the interface between the base and the slab is unbonded for the unrestrained slabs and bonded for the restrained slabs, indicating that the life of the bond might be a function of the restraint conditions. The primary factor affecting the measured deflections and strains was the slab restraint conditions.
Bibliographical Information:

Advisor:Dr. Julie Vandenbossche; Dr. Amir Koubaa; Dr. Jeen-Shang Lin

School:University of Pittsburgh

School Location:USA - Pennsylvania

Source Type:Master's Thesis

Keywords:civil and environmental engineering


Date of Publication:06/09/2008

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