Experimental and Analytical Investigations of Mechanistic Effects of Dowel Misalignment in Jointed Concrete Pavements

Abstract

This paper presents the results of experimental and analytical investigations on the effects of dowel misalignment on the joint opening behavior and distress in concrete pavement joints. It focuses on the development of three-dimensional (3-D) finite element models for computing the complex stress states and resulting damage in concrete pavement joints with misaligned dowels and, through experimental results, their validation. The concrete pavement is modeled by using a damage–plasticity material model, which uses concepts of damage–plasticity formulation in compression and cracking combined with damage elasticity in tension. The longitudinal bond between the steel dowel and the concrete is modeled in two parts. First, the longitudinal bond resulting from chemical adhesion, mechanical interlock, and static friction (in the aligned state) is modeled by means of spring elements. The nonlinear force–deformation relationship for the spring elements is derived from specific experimental results. Second, the longitudinal bond resulting from transverse interaction between steel dowels and the concrete pavement is modeled by surface-to-surface contact interaction elements and associated friction models. The 3-D finite element models are validated by the results of experimental investigations. These validated models provide significant insight into the 3-D stress states and principal stresses that develop in concrete pavement joints with misaligned dowels. They are used to evaluate analytically the effects of misalignment type, magnitude, uniformity, and distribution on the 3-D stress states and resulting damage in concrete pavements.

Experimental investigation on the combined effect of dowel misalignment and cyclic wheel loading on dowel bar performance in JPCP

“…Also, this selection was made to keep the distress surrounding the dowel bar localized without significant cracking during opening of the joint by 12 mm [10] to allow for the evaluation of LTE under cyclic load, after the slabs were pulled out and pushed back representing slab movement. Previous studies [5,10,11] showed that 12.5 mm misalignment (per half-length of the dowel) did not cause global failure of specimen. The third value of misalignment magnitude (25 mm) was adopted to investigate the effect of high misalignment magnitude as well as failure mechanism of the specimens due to joint lockup.…”

“…The results showed no signifcant difference in pull-out load for single misaligned dowel specimens, whereas a significant increase in pull-out load was observed for the specimens containing two misaligned dowels when the misalignment magnitude exceeded 12.7 mm per half dowel length.It should be noted that there are multiple dowels bars along a typical transverse joint and the interaction effect during pull-out can not be ignored [9]. Prabhu et al [5,10,11] carried out experimental as well as numerical investigations to produce guidelines for allowable dowel misalignment. Their investigations involved one, two, three and five 32 mm diameter steel dowel bars with different misalignment magnitudes (0, 6.35, 12.7, 19, and 25.4 mm per half-length of the dowel bar) and different misalignment types (vertical, horizontal and combined).…”

“…According to the standard pull-out load versus joint opening behaviour, debonding of the dowel bars from a concrete pavement consists of two parts [11,33]: (i) fully bonded to initial splitting part; in which, the dowels are assumed fully bonded until the start of the initial slipping. The behaviour during this stage is governed by the bond strength between the dowel bar and the concrete pavement surrounding it, as represented by Eq.1.…”

Effects of dowel bars misalignment in jointed plain concrete pavements – A numerical analysis considering thermal differentials and bonded slab-base interface

“…Over the last decades, investigations on concrete pavements mechanical behavior employing the finite element method (FEM) have increasingly spread. Most of these studies are concentrated on the load transfer efficiency analysis in concrete pavement joints with aligned dowel bars [13]. Only a limited number of investigations sought to understand the interaction mechanism between misaligned dowel bars and the concrete.…”

“…Only a limited number of investigations sought to understand the interaction mechanism between misaligned dowel bars and the concrete. Examples of such studies can be found elsewhere [13], [14], [15], [16].…”