Westergaard Curling Solution Reconsidered

Abstract

An in-depth and systematic examination is presented of the effect of temperature gradients on slab-on-grade pavements. The main objective for the examination was the development of practical design tools for use in a typical engineering office. This has been achieved by a critical reconsideration of the literature, a synthesis of currently available analytical resources, and the implementation of recent technological achievements promulgated in related areas of engineering. Prominent among these are the application of the principles of dimensional analysis, the finite element method, advanced statistical regression analysis, and artificial neural networks (ANN). A number of ANNs have been trained for the curling problem, and in several instances they are found to be more efficient predictive tools than corresponding statistical regression equations. It is found that the most important shortcomings of the Westergaard curling solution are the assumption of continuous contact between slab and subgrade (infinite slab self-weight) and the explicit treatment of only daytime conditions. Although Westergaard’s curling-only predictions are significantly inferior to those from ANN and statistics, his load-plus-curling predictions exhibit approximately the same scatter as those from these two more modern and nominally more sophisticated tools. The case of Westergaard’s curling solution can serve as an example pointing to the usefulness and desirability of theoretical solutions, even when these are achievable only on the basis of considerable abstraction and simplification.

Corner loading and curling stress analysis for concrete pavements — an alternative approach

“…Despite this argument, Ioannides et al (1985) later has indicated that the ILLI-SLAB finite element results closely fall between those predicted by Westergaard and Bradbury. The ILLI-SLAB stresses are the minor principal (tensile) stresses occurring at the top fiber of the slab corner.…”

Aplicabilidad del método de elementos finitos al análisis de las tensiones producidas en soleras de hormigón debido a las cargas transmitidas por los neumáticos de los tractores agrícolas

“…In the dimensioning of models the following has been considered: that the distance from the center of load application, the center of the tire forklift track, to the nearest edge of the slab must be greater than 1.75*L (Ioannides et al, 1985), where L is the relative stiffness (Eq [1]).…”

Analysis of rigid pavements under traffic loads using influence surfaces

“…The reference point shown in the figure is located at the mid-slab 300 mm away from the edge. Since tire pressure, tire contact area, and tire aspect ratio have an impact on the mechanistic responses of rigid pavements obtained from the finite element method (Ioannides et al 1985), wheel load may not be treated as a discrete point load. Thus, in the formation of influence surfaces, it is of importance to appropriately select contact pressure, contact area, and aspect ratio for the unit load.…”