Evaluation of Doweled Joints in Concrete Pavements Using Three-Dimensional Finite Element Analysis

Abstract

Transverse joints in rigid pavements are the locations where most pavement distress appears, leading to deteriorating riding quality and featuring high-maintenance costs. The state of stresses in the concrete surrounding dowel bars in dowel-jointed concrete pavements is a major factor that contributes to transverse joint distress. As such, a three-dimensional finite element model was developed for analyzing dowel-jointed concrete pavement. The effect of different pavement and joint related parameters on the load transfer characteristics of a joint has been evaluated using the finite element (FE) model. Group action of the dowel bar system has also been examined. Five loading cases were applied to replicate realistic vehicular loadings approaching and leaving the joint. The structural behavior of the pavement at the doweled joint was investigated for (1) pavement with and without voids, (2) dowel spacing variation, (3) pavement with and without lean concrete base, (4) slab thickness (5) tire pressure, and (6) single and dual wheel loads. The amount of load transfer was obtained from the shear force in the beam elements that simulate dowels. Results show that the voids underneath the joint causes an increase in the vertical displacement of the concrete slab and vertical stress at concrete/dowel bar interface, which could result in crushing of the concrete and dowel loosening. Wider dowel spacings result in increased shear forces and the size of the region containing engaged dowels does not change significantly with dowel spacing, only effecting the distribution of shear forces. Maximum principle stress (MPS) is about 6.7 times greater and steeper in the distribution pattern in the concrete pavement without lean concrete base (LCB). A thick concrete slab provides a significant benefit of higher load transfer and less curvature along the loaded side of the joint. The deformed shape explains why more dowels are engaged in the load transfer for the thicker concrete slab models. There were no significant effects on load transfer ratio with the increase applied wheel load. This phenomenon is also evident in the dowel shear force distribution. However, it will increases the demand on a few inner dowels beneath the wheel load, which may cause more damage to the joints and eventually lead to pavement failure. The study shows that the dowel bars perform effectively as a load transfer device in the concrete pavement system even under severe conditions.