Assessment of time-dependent structural resistance of RC bridges in the Barak valley region, Assam, India

2022 ◽  
pp. 1-32
Author(s):  
Joydeep Das ◽  
Arjun Sil
Keyword(s):  
Service Life ◽  
Structural Reliability ◽  
Strength Loss ◽  
Time Dependent ◽  
Load Variations ◽  
Reliability Models ◽  
Condition Rating ◽  
Structural Resistance ◽  
Dependent Parameter ◽  
Existing Bridges

The reinforced concrete (RC) bridges deteriorate essentially due to strength loss induced by aging of the structure, extreme weathering conditions, and unplanned increased service loads. However, these load variations and aging factors equally could compromise structural reliability, and service life for continuous satisfactory operation of service bridges for future performance. A reasonable model of bridge strength and applied loads becomes the basis of accurate prediction of bridge functionality. Hence, time-dependent reliability approaches could be used efficiently to gain a reliable understanding of issues facing by the bridges in the study area for appropriate solutions. In this paper, the reliability of bridges under harsh conditions studied using time-variant and time-invariant reliability models in which both load and resistance considered as a time-dependent parameter. A combination of condition rating (CR) and time-dependent load employed to attain accurate insights about the degradation of structural resistance of the existing bridges. The result shows the significant impact of aging as well as traffic loads influence in the service life of both national highways (NH) and rural road service bridges. These observations might be used to adopt appropriate planning strategies as well as rational decisions to ensure the safety of the bridges for future operation.

Simplified Method for Time-Dependent Reliability Analysis of Aging Bridges Subjected to Nonstationary Loads

2016 ◽  
Vol 23 (01) ◽  
pp. 1650003
Author(s):  
Cao Wang ◽  
Quanwang Li
Keyword(s):  
Structural Reliability ◽  
Operating Conditions ◽  
Time Dependent ◽  
Structural Resistance ◽  
Simplified Method ◽  
Increasing Trend ◽  
Live Loads ◽  
Load Intensity ◽  
Existing Bridges ◽  
Dimensional Integral

The performance of existing bridges may deteriorate in time due to aggressive environmental or operating conditions in service, which may eventually cause changes in structural resistance and reliability beyond the baseline assumed for new ones. In addition, the increasing trend of live loads applied to the bridges, which has been reported in many researches, also contributes to the reduction of structural reliability. In order to perform time-dependent reliability assessment for aging bridges subjected to nonstationary loading process with improved efficiency, a simplified method is proposed in this paper, where lower dimensional integral is involved in the calculation of reliability. With the proposed method, time-dependent reliability of a real aging RC bridge is conducted, and the effect of nonstationarity in load intensity on structural reliability is investigated. It is found that structural reliability is sensitive to the increase of load intensity, and is less sensitive to the varying mechanism of load intensity.

scholarly journals Scenarios for Life Cycle Studies of Bridge Concrete Structure Maintenance

2020 ◽  
Vol 12 (22) ◽  
pp. 9557
Author(s):  
Hyunsik Kim ◽  
Sungho Tae ◽  
Yonghan Ahn ◽  
Jihwan Yang
Keyword(s):  
Life Cycle ◽  
Service Life ◽  
Bridge Deck ◽  
Condition Rating ◽  
The Us ◽  
The Status ◽  
Future Events ◽  
Maintenance Activities ◽  
National Bridge Inventory ◽  
Existing Bridges

The sustainability of structures during their construction and service life has become a widespread topic of interest. To ensure the sustainability of bridges, maintenance databases can be analyzed to determine the status changes and required maintenance of existing bridges. The results of this analysis can then be used to predict the environmental impacts and costs incurred during ongoing maintenance of new bridges to prepare accordingly for the future. To prepare for future events, this study utilizes the US National Bridge Inventory to analyze changes in the condition rating of bridge decks and substructures according to their service years, and suggests maintenance scenarios for the service life of bridge deck and substructure concrete by investigating the maintenance activities according to service years. The factors for applying the scenarios in Korea and conceptual equations for life cycle studies which apply the scenarios are discussed for further study in the life cycle assessment field of bridges.

Research on resistance degradation and reliability of pre-stressed concrete structures in freeze-thaw zone

2018 ◽  
Vol 9 (4) ◽  
pp. 442-454
Author(s):  
Jinliang Liu ◽  
Yanmin Jia ◽  
Guanhua Zhang ◽  
Jiawei Wang
Keyword(s):  
Service Life ◽  
Structural Reliability ◽  
Concrete Structures ◽  
Calculation Model ◽  
Time Dependent ◽  
Content Type ◽  
Freeze Thaw ◽  
Remaining Service Life ◽  
Resistance Degradation ◽  
Thaw Zone

Purpose In the freeze-thaw zone, the pre-stressed concrete of bridge structure will be damaged by freezing-thawing, the bearing capacity of structure will decrease and the safety will be affected. The purpose of this paper is to establish the time-dependent resistance degradation model of structure in the freeze-thaw zone, and analysis the structural reliability and remaining service life in different freeze-thaw zones. Design/methodology/approach First, according to the theory of structural design, a calculation model of the resistance of pre-stressed concrete structures in f freeze-thaw zone is established. Second, the time-dependent resistance model was verified by the test beam bending failure test results done by the research group, which has been in service for 20 years in freeze-thaw zone. Third, using JC algorithm in MATLAB to calculate the index on the reliability of pre-stressed concrete structure in frozen thawed zones, forecasting the s remaining service life of structure. Findings First, the calculation model of the resistance of pre-stressed concrete structures in freeze-thaw zone is accurate and it has excellent applicability. Second, the structural resistance deterioration time in Wet-Warm-Frozen Zone is the earliest. Third, once the pre-stressed reinforcement rusts, the structural reliability index will reach limit value quickly. Finally, the remaining service life of structure meets the designed expectation value only in a few of freeze-thaw zones in China. Originality/value The research will provide a reference for the design on the durability of a pre-stressed concrete structure in the freeze-thaw zone. In order to verify the security of pre-stressed concrete structures in the freeze-thaw zone, engineers can use the model presented in this paper for durability checking, it has an important significance.

Functional and operational risk as a criterion for assessing the durability of an autonomous energy system

2019 ◽  
Vol 12 (1) ◽  
pp. 56-62 ◽  
Author(s):  
A. O. Nedosekin ◽  
A. V. Smirnov ◽  
D. P. Makarenko ◽  
Z. I. Abdoulaeva
Keyword(s):  
Service Life ◽  
Structural Reliability ◽  
Residual Life ◽  
Fuzzy Random Variable ◽  
Operational Risk ◽  
Energy System ◽  
Technical System ◽  
Residual Service Life ◽  
Technological Parameters ◽  
Residual Service

The article presents new models and methods for estimating the residual service life of an autonomous energy system, using the functional operational risk criterion (FOR). The purpose of the article is to demonstrate a new method of durability evaluation using the fuzzy logic and soft computing framework. Durability in the article is understood as a complex property directly adjacent to the complex property of system resilience, as understood in the Western practice of assessing and ensuring the reliability of technical systems. Due to the lack of reliable homogeneous statistics on system equipment failures and recoveries, triangular fuzzy estimates of failure and recovery intensities are used as fuzzy functions of time based on incomplete data and expert estimates. The FOR in the model is the possibility for the system availability ratio to be below the standard level. An example of the evaluation of the FOR and the residual service life of a redundant cold supply system of a special facility is considered. The transition from the paradigm of structural reliability to the paradigm of functional reliability based on the continuous degradation of the technological parameters of an autonomous energy system is considered. In this case, the FOR can no longer be evaluated by the criterion of a sudden failure, nor is it possible to build a Markov’s chain on discrete states of the technical system. Assuming this, it is appropriate to predict the defi ning functional parameters of a technical system as fuzzy functions of a general form and to estimate the residual service life of the technical system as a fuzzy random variable. Then the FOR is estimated as the possibility for the residual life of the technical system to be below its warranty period, as determined by the supplier of the equipment.

scholarly journals Estimation of Damage Induced by Single-Hole Rock Blasting: A Review on Analytical, Numerical, and Experimental Solutions

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 29
Author(s):  
Mahdi Shadabfar ◽  
Cagri Gokdemir ◽  
Mingliang Zhou ◽  
Hadi Kordestani ◽  
Edmond V. Muho
Keyword(s):  
Structural Reliability ◽  
Numerical Models ◽  
Experimental Models ◽  
Rock Blasting ◽  
Discussion Section ◽  
Reliability Models ◽  
Fine Grain ◽  
Experimental Approaches ◽  
Engineering Projects

This paper presents a review of the existing models for the estimation of explosion-induced crushed and cracked zones. The control of these zones is of utmost importance in the rock explosion design, since it aims at optimizing the fragmentation and, as a result, minimizing the fine grain production and recovery cycle. Moreover, this optimization can reduce the damage beyond the set border and align the excavation plan with the geometric design. The models are categorized into three groups based on the approach, i.e., analytical, numerical, and experimental approaches, and for each group, the relevant studies are classified and presented in a comprehensive manner. More specifically, in the analytical methods, the assumptions and results are described and discussed in order to provide a useful reference to judge the applicability of each model. Considering the numerical models, all commonly-used algorithms along with the simulation details and the influential parameters are reported and discussed. Finally, considering the experimental models, the emphasis is given here on presenting the most practical and widely employed laboratory models. The empirical equations derived from the models and their applications are examined in detail. In the Discussion section, the most common methods are selected and used to estimate the damage size of 13 case study problems. The results are then utilized to compare the accuracy and applicability of each selected method. Furthermore, the probabilistic analysis of the explosion-induced failure is reviewed using several structural reliability models. The selection, classification, and discussion of the models presented in this paper can be used as a reference in real engineering projects.

scholarly journals Time-Dependent Reliability Analysis of Reinforced Concrete Beams Subjected to Uniform and Pitting Corrosion and Brittle Fracture

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1820
Author(s):  
Mohamed El Amine Ben Seghier ◽  
Behrooz Keshtegar ◽  
Hussam Mahmoud
Keyword(s):  
Reinforced Concrete ◽  
Brittle Fracture ◽  
Reliability Analysis ◽  
Pitting Corrosion ◽  
Structural Reliability ◽  
Time Dependent ◽  
State Function ◽  
Rc Beams ◽  
Highly Nonlinear ◽  
Reliability Method

Reinforced concrete (RC) beams are basic elements used in the construction of various structures and infrastructural systems. When exposed to harsh environmental conditions, the integrity of RC beams could be compromised as a result of various deterioration mechanisms. One of the most common deterioration mechanisms is the formation of different types of corrosion in the steel reinforcements of the beams, which could impact the overall reliability of the beam. Existing classical reliability analysis methods have shown unstable results when used for the assessment of highly nonlinear problems, such as corroded RC beams. To that end, the main purpose of this paper is to explore the use of a structural reliability method for the multi-state assessment of corroded RC beams. To do so, an improved reliability method, namely the three-term conjugate map (TCM) based on the first order reliability method (FORM), is used. The application of the TCM method to identify the multi-state failure of RC beams is validated against various well-known structural reliability-based FORM formulations. The limit state function (LSF) for corroded RC beams is formulated in accordance with two corrosion types, namely uniform and pitting corrosion, and with consideration of brittle fracture due to the pit-to-crack transition probability. The time-dependent reliability analyses conducted in this study are also used to assess the influence of various parameters on the resulting failure probability of the corroded beams. The results show that the nominal bar diameter, corrosion initiation rate, and the external loads have an important influence on the safety of these structures. In addition, the proposed method is shown to outperform other reliability-based FORM formulations in predicting the level of reliability in RC beams.

The solution of an infinite set of differential-difference equations occurring in polymerization and queueing problems

1963 ◽  
Vol 59 (1) ◽  
pp. 117-124 ◽  
Author(s):  
A. Wragg
Keyword(s):  
Difference Equations ◽  
Queueing Theory ◽  
Bessel Functions ◽  
Formal Solution ◽  
Monomer Concentration ◽  
Arrival Rate ◽  
Time Dependent ◽  
Type Integral ◽  
Dependent Parameter ◽  
Infinite Set

AbstractThe time-dependent solutions of an infinite set of differential-difference equations arising from queueing theory and models of ‘living’ polymer are expressed in terms of modified Bessel functions. Explicit solutions are available for constant values of a parameter describing the arrival rate or monomer concentration; for time-dependent parameter a formal solution is obtained in terms of a function which satisfies a Volterra type integral equation of the second kind. These results are used as the basis of a numerical method of solving the infinite set of differential equations when the time-dependent parameter itself satisfies a differential equation.

The Time Dependent Reliability Analysis for the Deteriorated Reinforced Concrete Columns Using the Monte Carlo Simulation

2007 ◽  
Vol 345-346 ◽  
pp. 1385-1388
Author(s):  
Hee Kyu Kim ◽  
Young Kyun Hong ◽  
Jung Hyun Park
Keyword(s):  
Reinforced Concrete ◽  
Concrete Columns ◽  
Strength Loss ◽  
Reinforced Concrete Columns ◽  
Structural Resistance ◽  
Current Maximum ◽  
Maximum Crack ◽  
Corrosion Initiation Time ◽  
Corrosion Of Steel ◽  
Story Building

his study was prosecuted to analyze a structural resistance degradation model for the existing column in the 3-story building to be remodeled. The probabilistic random variables in this study were dealt with an initial member strength, current maximum crack width, current density and diameter of reinforcement with elapsed time and corrosion initiation time, TDRA has been performed to calculate the reliability index, the failure probability, the degradation level according to the member strength loss in reinforced concrete columns due to corrosion of steel reinforcement.

CORRECTION OF PREDICTION MODEL OUTPUT–APPLICATION TO GENERAL CORROSION MODEL

2021 ◽  
Vol 156 (A4) ◽  
Author(s):  
N Hifi ◽  
N Barltrop
Keyword(s):  
Prediction Model ◽  
Reliability Analysis ◽  
Model Calibration ◽  
Structural Reliability ◽  
Prediction Models ◽  
General Corrosion ◽  
Model Output ◽  
Reliability Models ◽  
Corrosion Model ◽  
Recorded Data

This paper applies a newly developed methodology to calibrate the corrosion model within a structural reliability analysis. The methodology combines data from experience (measurements and expert judgment) and prediction models to adjust the structural reliability models. Two corrosion models published in the literature have been used to demonstrate the technique used for the model calibration. One model is used as a prediction for a future degradation and a second one to represent the inspection recorded data. The results of the calibration process are presented and discussed.

scholarly journals Evolution of a domain wall in expanding universe: inflation and after it

2018 ◽  
Vol 191 ◽  
pp. 08004
Author(s):  
A.D. Dolgov ◽  
S.I. Godunov ◽  
A.S. Rudenko
Keyword(s):  
Domain Wall ◽  
Hubble Parameter ◽  
Domain Walls ◽  
Flat Space ◽  
Space Time ◽  
Time Dependent ◽  
Expanding Universe ◽  
Large Size ◽  
Dependent Parameter ◽  
Thick Domain Walls

We study the evolution of thick domain walls in the expanding universe. We have found that the domain wall evolution crucially depends on the time-dependent parameter C(t) = 1/(H(t)δ0)2, where H(t) is the Hubble parameter and δ0 is the width of the wall in flat space-time. For C(t) > 2 the physical width of the wall, a(t)δ(t), tends with time to constant value δ0, which is microscopically small. Otherwise, when C(t) ≤ 2, the wall steadily expands and can grow up to a cosmologically large size.

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