Probability of failure analysis in flexible pavements through the reliability concept

• Ano de defesa: 2021
• Autor(a) principal: Sanchez, Loana Henriquez
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Axle overload; Axle type; Confiabilidade; Flexible pavements; Pavimentos flexíveis; Pressão de enchimento; Probabilidade de falha; Probability of failure; Reliability; Sobrecarga; Tipo de eixo; Tire pressure
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/18/18143/tde-01102021-180342/

Pavement design involves the risk of the pavement life be shorter or even larger than the design life, which can result in undersized or oversized structure configurations and, as a consequence, generate an adverse economic impact for any highway agency. However, even though the probability-of-failure theory, as well as the reliability concept, have been incorporated in many pavement design procedures, there is a need for an accessible way to understand these concepts and also an easy procedure to apply them. This research aims to develop an alternative approach for a probability-of-failure analysis in flexible pavements based on the reliability concept, in order to capture important aspects that are often ignored in traditional reliability analysis of pavement structures, such as the undersizing or oversizing of structural configurations. Accordingly, four representative Brazilian pavement structures were studied from four structural responses that were calculated taking into account the effect of six different axle types subjected to five overload conditions and to three levels of tire pressure. The mePADS software was used to calculate the structural responses and empirical Asphalt Institute\'s pavement life predictions in terms of the number of cycles to failure for fatigue cracking (Nf) and rutting (Nr) pavement distresses were carried out. The smaller values between Nf and Nr were adopted as Critical Resistances while Solicitations were determined from the variation of Safety Factors (SF). In sequence, margin curves (M) involving average values and standard deviations were generated in order to identify the areas where the probability of failure might occur and finally the reliability indices (β) and the probabilities of failure (Pf) were obtained. Principal results showed that tandem-spaced and tandem axles are related to low β and Pf values mainly compared to single and dual axles. Furthermore, three of four multivariate linear regression models indicate strong and positive correlations and adequate levels of significance. In general, it was observed that a reliability-based analysis can be easily performed from accurate resistances and solicitations data that can be obtained from any criteria that provide the cycles to failure of the pavement structure configuration. The approach developed in this research is easy to be adopted in the engineering practice and thus has the potential to become a practice tool in the reliability-based mechanistic-empirical pavement design.