Finite element study of partial-depth cracks in restrained PCC slabs

Abstract

An existing finite element program—ISLAB2000—was modified to allow for the analysis of horizontally restrained and unrestrained portland cement concrete (PCC) pavement slabs with partial depth cracks. To simulate a partial-depth crack, special line spring elements were added to the ISLAB2000 finite element code. Previously published relationships between spring elements stiffness and crack depth were used for formulating the element stiffness matrix of the line spring elements and to calculate stress intensity factors after solving the system of finite element equations.

Several example problems of partially cracked PCC slabs subject to typical highway loadings were solved to verify this newly developed finite element model termed ISLAB2005. The impact of crack depth and base friction parameters on slabs stresses and deflections was investigated. On the basis of this analysis, ISLAB2005 was found to be a reliable tool for analysis of partially cracked pavements that are either restrained or unrestrained from horizontal movements.

Keywords:

• Finite element method
• partial-depth crack
• linear elastic fracture mechanics
• concrete pavement

Acknowledgements

This work was done under subcontract with the University of Michigan as part of a research study sponsored by the Michigan Department of Transportation (MDOT). The authors gratefully acknowledge the sponsorship of MDOT and the valuable contributions of Dr Will Hansen, Professor, Department of Civil Engineering, University of Michigan at Ann Arbor in accomplishing this work. MDOT assumes no liability for the content or use of the results of this study. This work does not constitute a standard, specification, or regulation.