Verification of NYSLAB a software for the analysis of jointed pavements

Maryam Limouee, University of Texas at El Paso

Abstract

A significant amount of research and development has been conducted for decades to provide a tool for the design and analysis of jointed slabs on different types of foundations. ILLI-SLAB, JSLAB, EverFE and ISLAB are the most used finite element modeling (FEM) codes that have gone through several iterations of improvement. JSLAB has been maintained by the Federal Highway Administration (FHWA) and is distributed free of charge and there is significant interest in further improving the capabilities of that software package.^ Researchers at the University of Texas at El Paso have been charged to implement several modifications in the latest version of JSLAB called JSLAB2004. A thorough review of JSLAB2004 source code that was developed in the 1970’s revealed that it would be beneficial to recode the software completely to take advantage of the modern programming and FEM tools available today. As such, a new code was developed in MATLAB that significantly enhances the efficiency and capabilities of JSLAB2004. The new software will be referred to as NYSlab hereafter. Some of the improvements include using isoparametric elements that capture shear deformations and allows flexibility to use unstructured meshes; and introducing gap elements to model the contact between several slabs and slab and foundation (instead of the ad-hoc algorithm currently used in JSLAB). There is also now no limitation on the number of slabs and foundation layers for defining a pavement structure. The simulation of temperature gradient is also improved for the modeling of curling of the slabs where the gradient can now be non-linear and exist in any number of slab layers.^ In addition to discussing the improvements to JSLAB2004 in this thesis, a comparison between the improved code and the other codes previously mentioned is also presented. Several studies were also conducted to determine the convergence characteristics of the FEM formulation. Finally, several parametric studies were conducted to verify the appropriate behavior of the code for different geometric configurations, foundation models and parameters, and temperature gradient profiles. ^ These studies indicate that the new code results compare well with the other codes and have good convergence characteristics. The parametric studies also demonstrate a well behaving code for various pavement-section configurations. ^ Key Words: Rigid Pavement, Convergence, Foundation Parameters, Foundation Type, Slab Dimension, Temperature Gradient.^

Subject Area

Engineering, Civil

Recommended Citation

Limouee, Maryam, "Verification of NYSLAB a software for the analysis of jointed pavements" (2009). ETD Collection for University of Texas, El Paso. AAI1473874.
http://digitalcommons.utep.edu/dissertations/AAI1473874

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