Stresses and Strains Prediction Model of Asphalt Pavements on Concrete Bridges

Traditional methods for the design of pavements cannot generally be applied for evaluating stresses and strains in asphalt pavements on concrete bridges. This paper presents a specific three-dimensional finite-element model (FE) that overcomes the limitation of the classical design approach that is implicitly in assuming pavements as being supported by foundation soils. Concrete bridges are generally formed by the deck, longitudinal beams and cross beams that behave globally in a way that is different from foundation soils. Based on the model developed, a finite-element software is used for estimating stresses and strains in pavements on bridges as a function of loads, temperatures, and dynamic modulus of an asphalt mixture. A simplified method for designing pavements on bridges is also derived from the results of the finite-element model. This method may be identified with a calculation based on the elastic multilayer system, which is represented by the layers of pavement and waterproofing, supported by a rigid half-space (concrete bridge deck). The simplified method represents a useful tool for a faster estimation of stresses and strains in asphalt pavements on concrete bridges at a preliminary design level. A preliminary design is used, for example, when the designer does not yet know the exact values of the input parameters concerning pavement and waterproofing, which will subsequently be measured for that specific bridge project, but uses the average values available or estimated from existing analytical correlations. The simplified method, although slightly less accurate, is not so time-consuming as the FE method. This latter method, in contrast, should be used when better information on the exact values of input parameters has been obtained from direct measurements (e.g. from laboratory tests)