Truck Weight Limit for Simply Supported Steel Girder Bridges Based on Bridge Fatigue Reliability

Abstract

The objective of this study was to present a new approach for determining the truck weight limit of simply supported steel girder bridges. This approach is based on the fatigue reliability of bridge girders under the action of random traffic flows considering the presence of multiple trucks. A simply supported steel girder bridge designed according to the current codes was used as the bridge model to illustrate the presented approach. Based on the collected traffic data from Wisconsin, random traffic flows were generated using the Monte Carlo method and were used as the traffic loading. Numerical simulations were carried out to investigate the effects of three important parameters, including the fraction of traffic in the fast lane (FTFL), violation rate (VR), and truck weight limit (TWL), on the average fatigue damage accumulation (AFDA) induced by each truck in the random traffic flow. Based on the Miner's cumulative damage model and the S-N curve, the effects of these parameters on the fatigue reliability index of bridge girders were also analyzed. The truck weight limit that can ensure the target fatigue reliability of the bridge girders after 75 years of service was determined based on the fatigue reliability analysis of the bridge girder.

ANN and LEFM-Based Fatigue Reliability Analysis and Truck Weight Limits of Steel Bridges after Crack Detection

“…In fact, previous studies indicated that the bending stresses of fatigue details at the mid-span govern the fatigue design of small and medium span bridges [15,18]. It should be noted that the fatigue detail of interest in the present study, which corresponds to the detail category B in the AASHTO LRFD [16], was also adopted as a typical fatigue detail in other studies [5,15]. The location and the dimensions of the crack in the fatigue detail are illustrated in Figure 4, in which w represents the thickness of the bottom flange, adopting a value of 22.2 mm, and the crack shape is presumed to be semi-elliptical, with a depth of a and a width of 2c.…”

“…This merging operation could lead to a little conservative result of the vehicle-induced fatigue damage because truck Class 4 and Class 12 account for a small percentage (7.48% in total) of the traffic flow and the GVWs of truck Class 4 and Class 12 are generally smaller than the GVWs of truck Class 5 and Class 13, respectively. A similar merging operation was also adopted in the research conducted by Wang et al [5]. The axle weight ratio, namely, the percentage of the axle weight to the GVW, and the mean axle spacing of each truck class are summarized in Figure 6, in which the circles represent the axles of each truck class, and the number marked above the circle represents the corresponding axle weight ratio.…”

“…Deng and Yan [4] proposed a new weight-limiting method that can consider the effect of fatigue damage under the cyclic loadings of trucks based on the theory of the S-N curve and Palmgren-Miner's rule. Furthermore, Wang et al [5] established a random traffic load model to consider the simultaneous existence of multiple trucks, and proposed a new method for determining the truck weight limit according to fatigue reliability analyses. However, these studies were performed on the basis of the theory of the S-N curve and Palmgren-Miner's rule, in which the effect of original cracks on the fatigue life of steel bridges can hardly be taken into account [6,7].…”

Damage Detection and Condition Assessment of Civil Structures

“…Li et al (2018d) present an innovative time-variant dimension updating method (TVDUM) for random traffic and bridges to study the coupled vehicle and bridge dynamic interactions. Wang et al (2018c) present a new approach for determining the truck weight limit of simply supported steel girder bridges based on the fatigue reliability of bridge girders under the action of random traffic flows considering the presence of multiple trucks. Han et al (2018a) analyze the site-specific load characteristics of extra-heavy trucks (EHTs) based on a weigh-in-motion (WIM) data measure.…”

Avaliação Do Ciclo De Vida De Pontes De Aço Considerando O Dano Por Fadiga E Corrosão

“…Esse sistema, entretanto, tem um custo elevado e acaba sendo mais apropriado para estruturas recém-construídas (Lu et al, 2016). Como alternativa, pesquisas foram realizadas com a integração de um sistema de pesagem em movimento WIM (Weigh In Motion, em inglês), que fornece dados de carregamento móvel, com a modelagem estrutural em elementos finitos (Cha et al, 2016;Guo et al, 2012;Kwon & Frangopol, 2010;Wang et al, 2018) e modelos preditivos (Lu et al, 2019;Lu et al, 2016;Zhu & Zhang, 2018) para avaliação do tempo de vida útil das estruturas.…”