scholarly journals Fatigue Assessment on Suspenders under Stochastic Wind and Traffic Loads Based on In-Situ Monitoring Data

2019 ◽  
Vol 9 (16) ◽  
pp. 3405 ◽  
Author(s):  
Mengxue Wu ◽  
Jin Zhu ◽  
Junlin Heng ◽  
Sakdirat Kaewunruen
Keyword(s):  
Fatigue Damage ◽  
Life Time ◽  
Suspension Bridge ◽  
In Situ Monitoring ◽  
Traffic Load ◽  
Monitoring Data ◽  
Fatigue Reliability ◽  
Fatigue Assessment ◽  
Traffic Loads

As a critical component of a suspension bridge, the integrity of the suspenders plays a critical role in the serviceability and reliability of the bridge during its life time. Despite the wide recognition of the importance of the suspenders, very few studies have been devoted to the condition evaluation of suspenders in operation. The present study performs the fatigue assessment on the suspenders accounting for the stochastic wind and traffic loads using the in-situ monitoring data. To this end, a probabilistic numerical framework is proposed to predict the time-dependent fatigue reliability of the suspenders under stochastic wind and traffic loads during the bridge’s life time, based on the linear fatigue damage rule. As a demonstration, the proposed numerical framework is applied to a long-span suspension bridge located in a mountainous canyon. The results indicate that it is of paramount importance to consider both the wind and traffic load effects in the fatigue reliability evaluation of the suspenders. In addition, it was also found that among the suspenders under investigation, the short suspender at the bridge mid-span (S36) is more prone to the fatigue damage, while the long suspender at the end of the bridge girder (S2) is less prone to the fatigue damage. Finally, provided with a target reliability index of 3.0, the fatigue life of the suspenders S36 and S2, considering the life time wind and traffic load, is estimated as 53 years and 167 years, respectively. The present research could provide essential guidelines for the optimization of inspection and replacement in maintenance practices for suspenders.

Probabilistic Fatigue Damage Analysis of Long Span Suspension Bridge Due to Wind Induced Buffeting

2020 ◽  
Vol 980 ◽  
pp. 275-281
Author(s):  
Hu Jun
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Time History ◽  
Suspension Bridge ◽  
Wind Load ◽  
Strong Wind ◽  
Fatigue Reliability ◽  
Long Span ◽  
Fatigue Damage Analysis ◽  
Fluctuating Wind

In order to consider the fluctuating wind load induced fatigue problem of long span suspension bridge, fatigue reliability formula is modified by assuming the fatigue life is accord with the weibull distribution. Based on the accurate bridge buffeting analysis of time history, the stress time history of components of a suspension bridge in east sea China is simulated, and then the fatigue damages and reliabilities are calculated. The results indicate that the main cables and hangers have enough fatigue reliability under the fluctuating wind load, the fatigue failure will not occur; the stiffening girder has larger fatigue damage, under 40 / (m.s-1) mean wind speed action, the girder of mid-support section’s average fatigue life is only 3.103 years, so the girder’s damage under strong wind action should be taken seriously.

scholarly journals Effect of High-Temperature Pavement Paving on Fatigue Durability of Bearing-Supported Steel Decks

2020 ◽  
Vol 10 (20) ◽  
pp. 7196
Author(s):  
Qiudong Wang ◽  
Bohai Ji ◽  
Zhongqiu Fu ◽  
Hao Wang
Keyword(s):  
High Temperature ◽  
Fatigue Damage ◽  
Temperature Stress ◽  
Damage Accumulation ◽  
Considerable Effect ◽  
In Situ Monitoring ◽  
Fatigue Durability ◽  
Residual Temperature ◽  
Fatigue Damage Accumulation

Orthotropic steel deck (OSD) is a better choice for urban bridges and the replacement of damaged concrete slabs. Gussasphalt concrete (GAC) is usually adopted as the asphalt surfacing; however, the paving temperature of GAC is high, which will affect the fatigue durability of fatigable welds in OSD. In this study, such influence of high-temperature pavement paving was comprehensively investigated based on in-situ monitoring and numerical analysis. The temperature of OSD and displacement of bearings were investigated based on the monitored data and numerical results. After that, the deformation and residual temperature stress of OSD during the paving process were analyzed. On this basis, the effect of residual temperature stress on fatigue damage accumulation of OSD was investigated and discussed. Results show that the uplift and expanded deformation of OSD arise during the paving process, leading to the displacement of bearings. Residual displacement of bearings, as well as the residual temperature stress at fatigable details of OSD, is observed. The residual temperature stress has considerable effect on fatigue damage accumulation at rib-deck weld. A fatigue damage amplification factor of 1.1 is recommended for taking into consideration of the adverse effect of high-temperature pavement paving.

scholarly journals Evaluating Probabilistic Traffic Load Effects on Large Bridges Using Long-Term Traffic Monitoring Data

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5056 ◽  
Author(s):  
Lu ◽  
Ma ◽  
Liu
Keyword(s):  
Control Measure ◽  
Heavy Traffic ◽  
Suspension Bridge ◽  
Traffic Monitoring ◽  
Traffic Load ◽  
Monitoring Data ◽  
Traffic Density ◽  
Maximum Deflection ◽  
Load Effects ◽  
Crossing Theory

With the steadily growing of global transportation market, the traffic load has increased dramatically over the past decades, which may develop into a risk source for existing bridges. The simultaneous presence of heavy trucks that are random in nature governs the serviceability limit for large bridges. This study investigated probabilistic traffic load effects on large bridges under actual heavy traffic load. Initially, critical stochastic traffic loading scenarios were simulated based on millions of traffic monitoring data in a highway bridge in China. A methodology of extrapolating maximum traffic load effects was presented based on the level-crossing theory. The effectiveness of the proposed method was demonstrated by probabilistic deflection investigation of a suspension bridge. Influence of traffic density variation and overloading control on the maximum deflection was investigated as recommendations for designers and managers. The numerical results show that the congested traffic mostly governs the critical traffic load effects on large bridges. Traffic growth results in higher maximum deformations and probabilities of failure of the bridge in its lifetime. Since the critical loading scenario contains multi-types of overloaded trucks, an effective overloading control measure has a remarkable influence on the lifetime maximum deflection. The stochastic traffic model and corresponding computational framework is expected to be developed to more types of bridges.

Parabolic-Apex Numerical Back-Analysis of Mechanics Parameters of Surrounding Rock

2012 ◽  
Vol 204-208 ◽  
pp. 196-201 ◽  
Author(s):  
Jian Cong Xu ◽  
Yi Wei Xu
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Pressure Coefficient ◽  
Back Analysis ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Monitoring Data ◽  
3D Fem ◽  
Physical Mechanics

The parabolic-apex numerical back-analysis method (PNBM) was proposed to obtain such physical-mechanics parameters as Young's modulus and lateral pressure coefficient of surrounding rock by 3D FEM numerical analysis based on in-situ monitoring data. Taking Xiang-an Subsea Tunnel (located in Xiamen, Fujian Province, China) for example, adopting the PNBM using ABAQUS software, three dimensional elastic-plastic FEM-PNBM of tunnel surrounding rock was validated using in-situ monitoring data. The results show as follows: Using the PNBM, not only may high calculation precision be obtained, better meeting the demand of actual projects, but also more reasonable and reliable physical mechanics indices of surrounding rock such as Young's modulus and lateral confinement pressure coefficient, may be obtained. The applicability and the simplicity of this proposed method also support its usefulness.

Satellite and in situ monitoring data used for modeling of forest vegetation reflectance

2010 ◽  
Author(s):  
M. A. Zoran ◽  
R. S. Savastru ◽  
D. M. Savastru ◽  
S. I. Miclos ◽  
M. N. Tautan ◽  
...  
Keyword(s):  
Forest Vegetation ◽  
In Situ Monitoring ◽  
Monitoring Data

Monitoring and Analysis on the Supporting Structure for Deep Foundation Pit

2014 ◽  
Vol 580-583 ◽  
pp. 787-790
Author(s):  
Hai Xia Sun ◽  
Ke Zhang ◽  
Si Li Chen
Keyword(s):  
In Situ Monitoring ◽  
Monitoring Data ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Metro Station ◽  
Deep Foundation Pit ◽  
Supporting Structure ◽  
Deformation Features ◽  
The Stability

This article mainly expounds the importance of in-situ monitoring on the construction process of deep foundation pit. Taking the deep foundation pit of some Shenyang metro station for example, the deformation features of the supporting structure and the internal and external of foundation pit is analyzed, according to the monitoring data of the fender pile displacement during the excavation of deep foundation pit. The conclusion is obtained that the timely and accurate in-situ monitoring information is necessary to guaranteeing construction safety. We should pay more attention to the excavation speed and exert the interior support timely during the excavation of foundation pit to avoid large deformation and danger. The analytical results of monitoring data shows that the whole stage of foundation pit excavation is stable and the fender pile with internal supports can guarantee the stability of foundation pit.

Influence of seasonal freezing on dynamic bridge characteristics using in-situ monitoring data

2019 ◽  
Vol 160 ◽  
pp. 184-193
Author(s):  
Anastasiia Plotnikova ◽  
Liam Wotherspoon ◽  
Sherif Beskhyroun ◽  
Zhaohui (Joey) Yang
Keyword(s):  
In Situ Monitoring ◽  
Monitoring Data ◽  
Seasonal Freezing

Numerical Simulation and Monitoring Analysis for High-Fill Slope

2013 ◽  
Vol 639-640 ◽  
pp. 274-278
Author(s):  
Liang Liang Duan ◽  
Guo Jing He ◽  
Jin Yi ◽  
Yue Feng Li
Keyword(s):  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
In Situ Monitoring ◽  
Monitoring Data ◽  
Main Process ◽  
Dynamic Design ◽  
Reinforcement Design ◽  
Fill Slope ◽  
Good Agreement

It is necessary to simulate construction and operation and analyze monitoring data in time for dynamic construction and reinforcement design of high-fill slope. As a typical example, some high-fill slope is calculated with limit equilibrium method for evaluation of the slope stability. The slope is also calculated with finite element method (FEM) and monitored during construction and operation. FEM stress and displacement results are in good agreement with in-situ monitoring data. Combining FEM computation with monitoring analysis is the main process of dynamic design which guides construction and reinforcement and assures safety.

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