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Hanger cable fatigue life assessment of a major suspension bridge
Published in Khaled M. Mahmoud, Risk-based Bridge Engineering, 2019
Making use of a Rainflow counting algorithm, stress reversal ranges and corresponding cycle counts are extracted from the time history results. An example of a stress time history and corresponding rainflow counts are presented in Figure 8 for hanger number 1. Hangers are numbered from 1 to 30 where 1 is the longest hanger located next to the tower and 30 is the shortest hanger at midspan.
Precast segmental bridge construction in seismic zones
Published in Fabio Biondini, Dan M. Frangopol, Bridge Maintenance, Safety, Management, Resilience and Sustainability, 2012
Fabio Biondini, Dan M. Frangopol
For the typical application envisioned for the wireless system, an embedded rainflow counting algorithm can significantly reduce the amount of transmitted data. For example, the desired sampling rate for the envisioned application is 50 samples/second. If a rainflow counting algorithm runs on continuously acquired strain data for 30 minutes, and transmits the results for each 30 minute period, the amount of transmitted data is reduced from 90,000 raw strain values to a single array of rainflow count values on the order of a couple hundred data points.
Short-crestedness effect on the dynamic response of offshore floating wind turbines
Published in Ships and Offshore Structures, 2022
Wind, wave and inertial loads applied at tower base cause stress fluctuation, which produces fatigue damage. The SN-based fatigue analysis software Mlife (NWTC 2017) developed by NREL is used to assess the fatigue damage at tower base. The fluctuating stress are broken down into individual hysteresis cycles by matching local minima with local maxima in the time series, which are characterised by a load-mean and range. The stress cycles are counted by the rainflow counting algorithm. It is assumed that the damage accumulates linearly with each of these cycles according to Miner’s Rule. In this case, the overall equivalent damage load (DL) produced by all the cycles is given by where nSTeq total equivalent fatigue counts. ni is the cycle count and Li is the cycle's load range. m is the Whöler exponent. m = 3 is used in this study.
Predicting fatigue damage of highway suspension bridge hangers using weigh-in-motion data and machine learning
Published in Structure and Infrastructure Engineering, 2021
Yang Deng, Meng Zhang, Dong-Ming Feng, Ai-Qun Li
The American Association of State Highways and Transportation Officials Load and Resistance Factor Design (AASHTO LRFD) proposed that the dynamic load allowance (impact factor) for all components except deck joints under fatigue limit state is 0.15 (AASHTO, 2010). In this study, the dynamic amplification factor DAF is set to 1.15. The rainflow counting algorithm (Downing & Socie, 1982) is used to extract the stress cycles from the time histories of the tension force. The fatigue damage is calculated by using the Miner ruler and S-N curve (Miner, 1945): where ni is the cycle number of the stress range Si; Ni is the fatigue life when the stress range is Si; D is the fatigue damage. The S-N curve of the hangers is: where, m and C are experimental parameters. m and C are 3.5 and 8.9125 × 1013, respectively (Zeng, Chen, & Tan, 2014).
Monitoring of the UHPFRC strengthened Chillon viaduct under environmental and operational variability
Published in Structure and Infrastructure Engineering, 2020
Henar Martín-Sanz, Konstantinos Tatsis, Vasilis K. Dertimanis, Luis David Avendaño-Valencia, Eugen Brühwiler, Eleni Chatzi
In the case of measured stress time histories, linear superposition of the different cycles is applied, evaluated via a cycle counting method. A widely adopted methodology to this end is the rainflow counting algorithm (Suresh, 1998). The fatigue properties or details are often described in terms of S – N curves, as depicted in Figure 32, where m = 4, MPa, MPa, and