Study on Fatigue Load and Fatigue Life Estimation for Concrete Bridges

2011 ◽  
Vol 243-249 ◽  
pp. 1536-1539
Author(s):  
Guo Dong Guan ◽  
Chun Sheng Wang ◽  
Gan Li ◽  
Yu Jiao Wang

Using truck weigh device, the data of traffic stream was collected from a toll station in Shaanxi province for 24 hours. A standard fatigue truck was developed based on the regular traffic data. Then S-N curves and Palgrem-Miner summation method was introduced in assessing fatigue life of the reinforcement in negative region of one continuous concrete bridge. It was concluded that the welding detail of reinforcement in negative region had long service life under normal traffic state. The fatigue life of reinforcement would be weakened considering overloading vehicles.

2011 ◽  
Vol 255-260 ◽  
pp. 1299-1302
Author(s):  
Chun Sheng Wang ◽  
Gan Li ◽  
Guo Dong Guan ◽  
Yu Jiao Wang

In the past ten years, considerable increases in traffic volume and vehicle loads have caused obviously fatigue damage in existing highway reinforced concrete bridges in China. Some highway reinforced concrete bridges were damaged seriously, leading to the whole bridge collapse sometimes because of overloading and oversize trucks. In order to observe the highway load character in Shaanxi province, truck weigh device is set up in highway pavement to measure axle weights and axle spacing. Based on these data, it can be classified and generalized the different classes of vehicles, and drawn out the simplifying fatigue truck model in Shaanxi province. Furthermore, the fatigue truck model was used to evaluate the fatigue life and service safety of typical concrete bridges.


Author(s):  
Xintian Liu ◽  
Yang Qu ◽  
Xiaobing Yang ◽  
Yongfeng Shen

Background:: In the process of high-speed driving, the wheel hub is constantly subjected to the impact load from the ground. Therefore, it is important to estimate the fatigue life of the hub in the design and production process. Objective:: This paper introduces a method to study the fatigue life of car hub based on the road load collected from test site. Methods:: Based on interval analysis, the distribution characteristics of load spectrum are analyzed. The fatigue life estimation of one - dimensional and two - dimensional load spectra is compared by compiling load spectra. Results:: According to the S-N curve cluster and the one-dimensional program load spectrum, the estimated range fatigue life of the hub is 397,100 km to 529,700 km. For unsymmetrical cyclic loading, each level means and amplitude of load were obtained through the Goodman fatigue empirical formula, and then according to S-N curve clusters in the upper and lower curves and two-dimensional program load spectrum, estimates the fatigue life of wheel hub of the interval is 329900 km to 435200 km, than one-dimensional load spectrum fatigue life was reduced by 16.9% - 17.8%. Conclusion:: This paper lays a foundation for the prediction of fatigue life and the bench test of fatigue durability of auto parts subjected to complex and variable random loads. At the same time, the research method can also be used to estimate the fatigue life of other bearing parts or high-speed moving parts and assemblies.


Author(s):  
Gustav Hultgren ◽  
Mansoor Khurshid ◽  
Peter Haglund ◽  
Zuheir Barsoum

AbstractA round-robin study has been carried out within a national project in Sweden with the addition of an international participant, where several industrial partners and universities are participating. The project aims to identify variation and sources of variation in welding production, map scatter in fatigue life estimation, and define and develop concepts to reduce these, in all steps of product development. The participating organisations were asked to carry out fatigue life assessment of welded box structures, which is a component in load-carrying structures. The estimations of fatigue life have also been compared with fatigue test results. Detailed drawings, loads and material data were also given to the participants. The participants were supposed to use assessment methods based on global and local stresses using the design codes or recommendations they currently use in-house. Differences were identified between both methods and participants using the same codes/recommendations. Applicability and conditions from the cases in the codes were also identified to be differently evaluated between the participants. It could be concluded that for the applied cases the nominal stress method often overestimated the fatigue life and had a high scatter in the estimations by different participants. The effective notch method is conservative in comparison to the life of tested components with little scatter between the results derived by the participants.


2021 ◽  
Vol 120 ◽  
pp. 105098
Author(s):  
Camilla Ronchei ◽  
Sabrina Vantadori

1997 ◽  
Vol 119 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Yanyao Jiang ◽  
Peter Kurath

Current research focuses on proportional cyclic hardening and non-Massing behaviors. The interaction of these two hardenings can result in the traditionally observed overall softening, hardening or mixed behavior exhibited for fully reversed strain controlled fatigue tests. Proportional experiments were conducted with five materials, 304 stainless steel, normalized 1070 and 1045 steels, and 7075-T6 and 6061-T6 aluminum alloys. All the materials display similar trends, but the 304 stainless steel shows the most pronounced transient behavior and will be discussed in detail. Existing algorithms for this behavior are evaluated in light of the recent experiments, and refinements to the Armstrong-Frederick class of incremental plasticity models are proposed. Modifications implemented are more extensive than the traditional variation of yield stress, and a traditional strain based memory surface is utilized to track deformation history. Implications of the deformation characteristics with regard to fatigue life estimation, especially variable amplitude loading, will be examined. The high-low step loading is utilized to illustrate the effect of transient deformation on fatigue life estimation procedures, and their relationship to the observed and modeled deformation.


2014 ◽  
Author(s):  
Luiz Henrique Bresser Cardoso de Mello ◽  
Fábio Comes de Castro

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