Symptom-Based Reliability Analysis and Remaining Service Life Prediction of Deteriorating RC Structures

2013 ◽  
Vol 569-570 ◽  
pp. 151-158
Author(s):  
Tian Li Huang ◽  
Hua Peng Chen
Keyword(s):  
Service Life ◽  
Reliability Analysis ◽  
Numerical Study ◽  
Weibull Model ◽  
Reinforcement Corrosion ◽  
Analysis Method ◽  
Resistance Development ◽  
Rc Structures ◽  
Remaining Service Life ◽  
Flexural Resistance

This paper proposes a symptom-based reliability analysis method for deteriorating reinforced concrete (RC) structures on the basis of monitored data. The structural flexural resistance due to reinforcement corrosion is selected as a symptom which reflects the deteriorating structural performance. The symptom reliability and remaining service life are then estimated from the Weibull model for the structural flexural resistance development. The results for the numerical study example show the proposed approach is capable of prediction the remaining service life for the deteriorating RC structures subjected to the reinforcement corrosion.

Residual Service Life Prediction of Offshore Concrete Structures With Chloride-Induced Damage: The State of the Art

2013 ◽  
Author(s):  
S. M. S. M. K. Samarakoon ◽  
R. M. Chandima Ratnayake
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Prediction Models ◽  
Laboratory Data ◽  
Concrete Structures ◽  
Residual Service Life ◽  
Reinforcement Corrosion ◽  
Rc Structures ◽  
Maintenance And Repair ◽  
Remaining Service Life

Offshore oil and gas (O&G) production and process facilities (P&PFs) consist of concrete components and structures with steel reinforcement and pre-stressing tendons. They are vulnerable to deterioration due to chloride-induced damage from being exposed to the severe marine environment. The aforementioned deterioration creates significant challenges to the life extension analysis presently required for P&PFs located in the North Sea. Currently, maintenance work has been carried out via in-service inspection and condition monitoring to assure the structural integrity at a pre-specified level of P&PFs. In this context, the knowledge from existing models forms a basis for making quantitative predictions of the remaining service life of structures and components made of concrete. The service life of reinforced concrete structures in relation to reinforcement corrosion is usually modeled considering the initiation period and the corrosion propagation period. The formation of optimal proactive maintenance and repair strategies for corrosion-damaged reinforced concrete (RC) structures is highly dependent on the results of prediction models. The combination of both field (i.e. inspection) and laboratory data with numerical modeling helps the formulation of models for the prediction of the time to pre-defined limit states or to estimate the time for carrying out necessary maintenance and repair. This manuscript provides a review of the available methods for predicting the remaining service life of RC structures in relation to reinforcement corrosion. It also highlights suitable methods for predicting the remaining service life of offshore ageing concrete structures in a severe corrosive environment.

A Possible Basis for Nondestructive Characterization of Ropes of Nylon 6

1997 ◽  
Vol 503 ◽  
Author(s):  
H. Jiang ◽  
M. K. Davis ◽  
R. K. Eby ◽  
P. Arsenovic
Keyword(s):  
Tensile Strength ◽  
Service Life ◽  
Fiber Diameter ◽  
Structural Parameters ◽  
Crystal Form ◽  
Nylon 6 ◽  
Remaining Service Life ◽  
Nondestructive Characterization ◽  
Fractional Content

ABSTRACTPhysical properties and structural parameters have been measured for ropes of nylon 6 as a function of the number of use operations. The fractional content of the α crystal form, sound velocity, birefringence, tensile strength and length all increase systematically and significantly with increasing the number of use operations. The fractional content of the γ crystal form and fiber diameter decrease with use. These trends indicate that the measurement of such properties and structural parameters, especially the length, provide a possible basis for establishing a reliable, rapid, and convenient nondestructive characterization method to predict the remaining service life of nylon 6 ropes.

scholarly journals An Efficient Time-Variant Reliability Analysis Method with Mixed Uncertainties

Algorithms ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 229
Author(s):  
Fangyi Li ◽  
Yufei Yan ◽  
Jianhua Rong ◽  
Houyao Zhu
Keyword(s):  
Reliability Analysis ◽  
Limit State ◽  
Random Variables ◽  
Equivalent Model ◽  
Independent Random Variables ◽  
Problem Analysis ◽  
Analysis Method ◽  
Calculation Algorithm ◽  
Reliability Problem ◽  
Interval Variables

In practical engineering, due to the lack of information, it is impossible to accurately determine the distribution of all variables. Therefore, time-variant reliability problems with both random and interval variables may be encountered. However, this kind of problem usually involves a complex multilevel nested optimization problem, which leads to a substantial computational burden, and it is difficult to meet the requirements of complex engineering problem analysis. This study proposes a decoupling strategy to efficiently analyze the time-variant reliability based on the mixed uncertainty model. The interval variables are treated with independent random variables that are uniformly distributed in their respective intervals. Then the time-variant reliability-equivalent model, containing only random variables, is established, to avoid multi-layer nesting optimization. The stochastic process is first discretized to obtain several static limit state functions at different times. The time-variant reliability problem is changed into the conventional time-invariant system reliability problem. First order reliability analysis method (FORM) is used to analyze the reliability of each time. Thus, an efficient and robust convergence hybrid time-variant reliability calculation algorithm is proposed based on the equivalent model. Finally, numerical examples shows the effectiveness of the proposed method.

scholarly journals Modelling of Corrosion-Induced Concrete Cover Cracking Due to Chloride Attacking

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1440
Author(s):  
Pei-Yuan Lun ◽  
Xiao-Gang Zhang ◽  
Ce Jiang ◽  
Yi-Fei Ma ◽  
Lei Fu
Keyword(s):  
Service Life ◽  
Corrosion Current ◽  
Practical Experience ◽  
Concrete Cover ◽  
Premature Failure ◽  
Rc Structures ◽  
Structural Capacity ◽  
Cover Cracking ◽  
Deterioration Process ◽  
Cracking Process

The premature failure of reinforced concrete (RC) structures is significantly affected by chloride-induced corrosion of reinforcing steel. Although researchers have achieved many outstanding results in the structural capacity of RC structures in the past few decades, the topic of service life has gradually attracted researchers’ attention. In this work, based on the stress intensity, two models are developed to predict the threshold expansive pressure, corrosion rate and cover cracking time of the corrosion-induced cracking process for RC structures. Specifically, in the proposed models, both the influence of initial defects and modified corrosion current density are taken into account. The results given by these models are in a good agreement with practical experience and laboratory studies, and the influence of each parameter on cover cracking is analyzed. In addition, considering the uncertainty existing in the deterioration process of RC structures, a methodology based on the third-moment method in regard to the stochastic process is proposed, which is able to evaluate the cracking risk of RC structures quantitatively and predict their service life. This method provides a good means to solve relevant problems and can prolong the service life of concrete infrastructures subjected to corrosion by applying timely inspection and repairs.

scholarly journals Comparison of reliability evaluation methods between China and Canada standards for wood structures featuring duration of load

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
Qiongyao Wu ◽  
Shuang Niu ◽  
Enchun Zhu
Keyword(s):  
Reliability Analysis ◽  
Analysis Method ◽  
Safety Level ◽  
Wood Structures ◽  
Load Effect ◽  
Key Factor ◽  
Live Loads ◽  
High Level ◽  
Partial Factor ◽  
Duration Of Load

Abstract Duration of load (DOL) is a key factor in design of wood structures, which makes the reliability analysis of wood structures more complicated. The importance of DOL is widely recognized, yet the methods and models through which it is incorporated into design codes vary substantially by country/region. Few investigations of the effect of different model assumptions of DOL and other random variables on the results of reliability analysis of wood structures can be found. In this paper, comparisons are made on the reliability analysis methods that underlie the China and the Canada standards for design of wood structures. Main characteristics of these two methods, especially the way how DOL is treated are investigated. Reliability analysis was carried out with the two methods employing the same set of material properties and load parameters. The resulted relationships between reliability index β and resistance partial factor γR* (the β–γR* curves) for four load combinations are compared to study the safety level indicated by the two methods. The comparison shows that the damage accumulation model (Foschi–Yao model) in the Canada analysis method is highly dependent on the type and duration of load, resulting in more conservative design than the China analysis method in loading cases dominated by dead load, but less conservative design in cases of high level of live loads. The characteristics of the load effect term of the performance function are also found to make considerable difference in reliability levels between the two methods. This study aims to provide references for researchers and standard developers in the field of wood structures.

Uncertain time-dependent reliability analysis of corroded RC structures applying three-term conjugate method

2020 ◽  
Vol 115 ◽  
pp. 104599 ◽  
Author(s):  
Mansour Bagheri ◽  
Seyed Abbas Hosseini ◽  
Behrooz Keshtegar ◽  
José A.F.O. Correia ◽  
Nguyen-Thoi Trung
Keyword(s):  
Reliability Analysis ◽  
Time Dependent ◽  
Rc Structures ◽  
Uncertain Time
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