The Experts below are selected from a list of 1893 Experts worldwide ranked by ideXlab platform
A.a. Roubos - One of the best experts on this subject based on the ideXlab platform.
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time dependent reliability analysis of service proven Quay Walls subject to corrosion induced degradation
Reliability Engineering & System Safety, 2020Co-Authors: A.a. Roubos, T Schweckendiek, Raphael D J M Steenbergen, Diego L Allaix, S N JonkmanAbstract:Abstract The assessment of service-proven Quay Walls subject to corrosion-induced degradation is inherently a time-dependent reliability problem. Two major challenges are the modelling of corrosion and taking into account the decrease of epistemic uncertainty throughout the Quay wall's service life. The main objective of this study is to examine the probability of failure, despite successful past performance, when the Quay wall is subject to corrosion and randomly imposed variable loads. The development of the annual failure rate is modelled using crude Monte Carlo and by performing a first-order system reliability analysis. The annual failure rates found for service-proven Quay Walls vary over time. For those with successful service histories and subject to low corrosion rates, the highest reliability indices are observed in the first year of the service life, whereas with higher corrosion rates the final year prevails. In general, it seems more practical to evaluate reliability on an annual basis rather than over longer time periods, since the latter will introduce an iterative procedure to determine the wall's remaining lifetime. The key findings of this study can be crucial for the lifetime extension of existing Quay Walls, and presumably also for other service-proven geotechnical structures subject to corrosion.
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finite element based reliability assessment of Quay Walls
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 2020Co-Authors: A.a. Roubos, T Schweckendiek, R B J Brinkgreve, Raphael D J M Steenbergen, S N JonkmanAbstract:While reliability methods have already been widely adopted in civil engineering, the efficiency and robustness of finite element-based reliability assessments of Quay Walls are still fairly low. In...
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target reliability indices for existing Quay Walls derived on the basis of economic optimisation and human safety requirements
Structure and Infrastructure Engineering, 2020Co-Authors: A.a. Roubos, Raphael D J M Steenbergen, Diego L Allaix, K Fischer, S N JonkmanAbstract:General frameworks for reliability differentiation have evolved over time and are mainly developed for buildings. However, recommendations for the safety of existing Quay Walls are lacking. In this study, target reliability indices for assessing existing Quay Walls were derived by economic optimisation and by evaluating the requirements concerning human safety. In Quay-wall design, some dominant stochastic design variables are largely time-independent, such as soil and material properties. The influence of time-independent variables on the evolution of the probability of failure was taken into consideration, since this affects the present value of future failure costs and the associated target reliability indices. The target reliability indices obtained for existing Quay Walls depend on the consequences of failure and the remaining lifetime. If the failure modes of a Quay wall are governed by time-independent design parameters and the Quay wall has already survived the early service period, the residual probability of failure is lower for an existing Quay wall compared to a new structure. Hence, this should be considered in the determination of target reliability indices. The method to evaluate Quay-wall reliability over time can also be used to assess other civil and geotechnical structures.
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enhancing reliability based assessments of Quay Walls
2019Co-Authors: A.a. RoubosAbstract:In the coming years, thousands of Quay Walls will approach the end of their intended fifty-year design lifetime and become part of lifetime extension programmes throughout the world. It is presently unclear how reliable these structures are and whether they are still capable of bearing ship and crane loads. An appropriate assessment of a Quay wall’s reliability is essential to safely and responsibly determining its remaining service life. This thesis demonstrates how Quay wall reliability can be evaluated and what aspects should be taken into consideration.
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relationship between the construction costs and the reliability index of Quay Walls
Microelectronics Systems Education, 2019Co-Authors: Robbin Wesstein, J G De Gijt, O M Heeres, A.a. RoubosAbstract:Structures, such as Quay Walls, have to meet a particular level of safety. Consequently, in the Eurocode standards, three reliability classes are distinguished, each corresponding to a target reliability index and set of partial factors. In this study, more insight is acquired into the relationship between the Quay wall's construction costs and the associated reliability index β. It appeared that the marginal costs of safety investments of Quay Walls are fairly low and in the same order of magnitude of the uncertainty of the estimate of the construction costs. Hence, it seems that the current reliability classes, as defined in the Eurocode standards, are non-efficient for Quay Walls. In addition, this study investigates the influence of the partial factors and three failure mechanisms on the construction costs and the reliability index. It was concluded that for the considered cases, the soil's angle of internal friction strongly influences the construction costs and the β of the Quay wall. Furthermore, it follows that economic optimisation in the probabilistic design of Quay Walls is possible by increasing the target reliability index of the failure mechanism 'insufficient passive soil resistance' and decrease the target reliability index of 'yielding of sheet pile profile'.
Ikuo Towhata - One of the best experts on this subject based on the ideXlab platform.
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displacement reducer fuses for improving seismic performance of caisson Quay Walls
Bulletin of Earthquake Engineering, 2011Co-Authors: Amirali Mostafavi Moghadam, Abbas Ghalandarzadeh, Ikuo Towhata, Majid Moradi, Pouria HajialikhaniAbstract:This research is to study the efficiency of displacement reducer fuses, installed behind the caisson Quay Walls for controlling the dynamic backfill thrust and minimizing the displacement, settlement and tilting of the Walls. For this purpose, two types of fuses, Displacement Reducer Panels (DRP) and Displacement Reducer Elements (DRE), were constructed and installed behind the wall. The DRPs were constructed by hollow Polypropylene sheets to reproduce elastoplastic and plastic mechanical behaviors. The DREs were cylindrical stainless-steel dampers, working upon friction mechanism that can reproduce perfect plastic behavior. Here, two series of shaking table 1-g tests were performed with DRP and DRE applications. In this regard, different mechanical behaviors and capacities were considered for fuses against demand thrusts of backfill in order to compare the mitigation tests with no-mitigation cases. Harmonic base motions with constant amplitude and constant frequency were used in the model test. The foundation soil and the backfill soil were constructed with the relative densities of 85 and 25%, respectively, to reproduce non-liquefiable base layer and loose backfill situations in the model, respectively. The results showed remarkable reduction in kinetic energy, dynamic backfill thrust and consequently seaward movement, settlement and inclination of the caisson Quay wall in case of using fuses with plastic behaviors behind the wall.
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Displacement reducer fuses for improving seismic performance of caisson Quay Walls
Bulletin of Earthquake Engineering, 2011Co-Authors: Amirali Mostafavi Moghadam, Mohsen Moradi, Abbas Ghalandarzadeh, Ikuo Towhata, Pouria HajialikhaniAbstract:This research is to study the efficiency of displacement reducer fuses, installed behind the caisson Quay Walls for controlling the dynamic backfill thrust and minimizing the displacement, settlement and tilting of the Walls. For this purpose, two types of fuses, Displacement Reducer Panels (DRP) and Displacement Reducer Elements (DRE), were constructed and installed behind the wall. The DRPs were constructed by hollow Polypropylene sheets to reproduce elastoplastic and plastic mechanical behaviors. The DREs were cylindrical stainless-steel dampers, working upon friction mechanism that can reproduce perfect plastic behavior. Here, two series of shaking table 1-g tests were performed with DRP and DRE applications. In this regard, different mechanical behaviors and capacities were considered for fuses against demand thrusts of backfill in order to compare the mitigation tests with no-mitigation cases. Harmonic base motions with constant amplitude and constant frequency were used in the model test. The foundation soil and the backfill soil were constructed with the relative densities of 85 and 25%, respectively, to reproduce non-liquefiable base layer and loose backfill situations in the model, respectively. The results showed remarkable reduction in kinetic energy, dynamic backfill thrust and consequently seaward movement, settlement and inclination of the caisson Quay wall in case of using fuses with plastic behaviors behind the wall. © 2011 Springer Science+Business Media B.V.
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studying the effects of deformable panels on seismic displacement of gravity Quay Walls
Ocean Engineering, 2009Co-Authors: Amirali Mostafavi Moghadam, Babak Ebrahimian, Abbas Ghalandarzadeh, Ikuo Towhata, Majid Moradi, Pouria HajialikhaniAbstract:Abstract This research is to investigate the effects of deformable panels on reducing the seaward displacement, settlement and tilting of caisson Quay Walls. In this regard, a series of shaking table 1-g tests are performed for a 1 25 scaled-down caisson Quay wall with two different seabed interface conditions. Here, the wall is tested in two cases: with and without (no-mitigation case) applying the deformable panels. Being installed behind the Walls, the panels applied in the tests have different mechanical properties. In the model test, the harmonic base motions are used with constant frequency and amplitude. In all tests, the foundation soil beneath the caisson wall is assumed as dense and non liquefiable. However, in order to reproduce a loose backfill situation in the model, the backfill soil is constructed with relative density of 25%. Furthermore, to support the experimental results, a series of finite difference effective-stress analyses are performed in the prototype scale. The mitigation results show that the deformable panels can significantly decrease the seaward movement, settlement and inclination of wall as well as the total pressure recorded behind the caisson wall. Here, these panels are called Displacement Reducer Panels (DRP) based on the obtained results.
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model tests on behaviour of gravity type Quay Walls subjected to strong shaking
Bulletin of the New Zealand National Society for Earthquake Engineering, 2009Co-Authors: Ikuo Towhata, Jahangir Alam, Tsuyoshi Honda, Satoshi TamateAbstract:SUMMARY Seismic stability of gravity-type Quay Walls and prevention of their large distortion are of major concern from a disaster prevention view point as well as in the sense of successful restoration after strong seismic events. There are, however, many existing Walls which are of limited seismic resistance and would not be safe under increasing magnitude of design earthquakes. The present study conducted shaking model tests in both 1-g and 50-g centrifugal fields in order to demonstrate the efficiency of available mitigation technologies. Test results suggest that soil improvement in the loose foundation sand can reduce the Quay wall damage to a certain extent when the intensity of shaking is around 0.30g. In contrast, under stronger shaking, the centrifugal tests manifested that those measures are not promising because of the increased effects of seismic inertia force.
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Studying the effects of deformable panels on seismic displacement of gravity Quay Walls
Ocean Engineering, 2009Co-Authors: Amirali Mostafavi Moghadam, Babak Ebrahimian, Mohsen Moradi, Abbas Ghalandarzadeh, Ikuo Towhata, Pouria HajialikhaniAbstract:This research is to investigate the effects of deformable panels on reducing the seaward displacement, settlement and tilting of caisson Quay Walls. In this regard, a series of shaking table 1-g tests are performed for a frac(1, 25) scaled-down caisson Quay wall with two different seabed interface conditions. Here, the wall is tested in two cases: with and without (no-mitigation case) applying the deformable panels. Being installed behind the Walls, the panels applied in the tests have different mechanical properties. In the model test, the harmonic base motions are used with constant frequency and amplitude. In all tests, the foundation soil beneath the caisson wall is assumed as dense and non liquefiable. However, in order to reproduce a loose backfill situation in the model, the backfill soil is constructed with relative density of 25%. Furthermore, to support the experimental results, a series of finite difference effective-stress analyses are performed in the prototype scale. The mitigation results show that the deformable panels can significantly decrease the seaward movement, settlement and inclination of wall as well as the total pressure recorded behind the caisson wall. Here, these panels are called Displacement Reducer Panels (DRP) based on the obtained results. © 2009 Elsevier Ltd. All rights reserved.
Abbas Ghalandarzadeh - One of the best experts on this subject based on the ideXlab platform.
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dynamic pore water pressure of submerged backfill on caisson Quay Walls 1 g shake table tests
Soil Dynamics and Earthquake Engineering, 2020Co-Authors: Abbas Ghalandarzadeh, Salman Rahimi, Ali KavandAbstract:Abstract This paper aims to investigate dynamic pore water pressure of submerged backfill on caisson Quay Walls implementing 1 g shake table physical model tests. The tests were performed on physical models instrumented with various types of transducers to record different aspects of the behavior of the Quay Walls and the backfill soil during shaking. The results showed that dynamic pore water pressures exerted on the Quay Walls were influenced by several parameters including relative density and permeability of the backfill, amplitude of base shaking, generation of excess pore water pressure in the backfill and lateral displacement of the Quay wall. A comparison between the experimental results and the available analytical solutions demonstrated that the analytical solutions cannot accurately predict dynamic pore water pressures in backfills of intermediate permeability where soil-water interaction is substantial. Also, it was found that in the worst-case scenario, two out of three different dynamic thrusts exerted on the Quay wall including active dynamic pressure of the backfill, dynamic pore water pressure and hydrodynamic pressure were in phase. Moreover, the variation of each of these pressures with depth was not necessarily in phase.
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experimental study of remediation measures of anchored sheet pile Quay Walls using soil compaction
Ocean Engineering, 2015Co-Authors: Ashraf Zekri, Abbas Ghalandarzadeh, Pooyan Ghasemi, M H AminfarAbstract:The seismic performance of Quay Walls was determined to be highly dependent on liquefaction. The dynamic response of anchored sheet pile Quay Walls that are embedded in liquefaction-susceptible soil was investigated using shaking table modeling. Extensive damage to the retaining system was attributed to the soil liquefaction near the embedded section. The lateral displacements of the Walls due to liquefaction were accompanied by large seaward displacements of anchors; they consequently reduced the tensile forces of the tie rods. A remediation method that involves the compaction of weak areas was experimentally evaluated. The effectiveness of the soil improvement in zones adjacent to the embedded section and/or the area in front of the anchors was assessed based on recorded dynamic responses. The implemented countermeasures considerably reduced the deformations of the wall and the anchors. The foundation improvements influenced the failure mode. Densification in front of the anchors limited the seaward displacements of the anchors, which increased the tensile forces in the tie rods.
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displacement reducer fuses for improving seismic performance of caisson Quay Walls
Bulletin of Earthquake Engineering, 2011Co-Authors: Amirali Mostafavi Moghadam, Abbas Ghalandarzadeh, Ikuo Towhata, Majid Moradi, Pouria HajialikhaniAbstract:This research is to study the efficiency of displacement reducer fuses, installed behind the caisson Quay Walls for controlling the dynamic backfill thrust and minimizing the displacement, settlement and tilting of the Walls. For this purpose, two types of fuses, Displacement Reducer Panels (DRP) and Displacement Reducer Elements (DRE), were constructed and installed behind the wall. The DRPs were constructed by hollow Polypropylene sheets to reproduce elastoplastic and plastic mechanical behaviors. The DREs were cylindrical stainless-steel dampers, working upon friction mechanism that can reproduce perfect plastic behavior. Here, two series of shaking table 1-g tests were performed with DRP and DRE applications. In this regard, different mechanical behaviors and capacities were considered for fuses against demand thrusts of backfill in order to compare the mitigation tests with no-mitigation cases. Harmonic base motions with constant amplitude and constant frequency were used in the model test. The foundation soil and the backfill soil were constructed with the relative densities of 85 and 25%, respectively, to reproduce non-liquefiable base layer and loose backfill situations in the model, respectively. The results showed remarkable reduction in kinetic energy, dynamic backfill thrust and consequently seaward movement, settlement and inclination of the caisson Quay wall in case of using fuses with plastic behaviors behind the wall.
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Displacement reducer fuses for improving seismic performance of caisson Quay Walls
Bulletin of Earthquake Engineering, 2011Co-Authors: Amirali Mostafavi Moghadam, Mohsen Moradi, Abbas Ghalandarzadeh, Ikuo Towhata, Pouria HajialikhaniAbstract:This research is to study the efficiency of displacement reducer fuses, installed behind the caisson Quay Walls for controlling the dynamic backfill thrust and minimizing the displacement, settlement and tilting of the Walls. For this purpose, two types of fuses, Displacement Reducer Panels (DRP) and Displacement Reducer Elements (DRE), were constructed and installed behind the wall. The DRPs were constructed by hollow Polypropylene sheets to reproduce elastoplastic and plastic mechanical behaviors. The DREs were cylindrical stainless-steel dampers, working upon friction mechanism that can reproduce perfect plastic behavior. Here, two series of shaking table 1-g tests were performed with DRP and DRE applications. In this regard, different mechanical behaviors and capacities were considered for fuses against demand thrusts of backfill in order to compare the mitigation tests with no-mitigation cases. Harmonic base motions with constant amplitude and constant frequency were used in the model test. The foundation soil and the backfill soil were constructed with the relative densities of 85 and 25%, respectively, to reproduce non-liquefiable base layer and loose backfill situations in the model, respectively. The results showed remarkable reduction in kinetic energy, dynamic backfill thrust and consequently seaward movement, settlement and inclination of the caisson Quay wall in case of using fuses with plastic behaviors behind the wall. © 2011 Springer Science+Business Media B.V.
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studying the effects of deformable panels on seismic displacement of gravity Quay Walls
Ocean Engineering, 2009Co-Authors: Amirali Mostafavi Moghadam, Babak Ebrahimian, Abbas Ghalandarzadeh, Ikuo Towhata, Majid Moradi, Pouria HajialikhaniAbstract:Abstract This research is to investigate the effects of deformable panels on reducing the seaward displacement, settlement and tilting of caisson Quay Walls. In this regard, a series of shaking table 1-g tests are performed for a 1 25 scaled-down caisson Quay wall with two different seabed interface conditions. Here, the wall is tested in two cases: with and without (no-mitigation case) applying the deformable panels. Being installed behind the Walls, the panels applied in the tests have different mechanical properties. In the model test, the harmonic base motions are used with constant frequency and amplitude. In all tests, the foundation soil beneath the caisson wall is assumed as dense and non liquefiable. However, in order to reproduce a loose backfill situation in the model, the backfill soil is constructed with relative density of 25%. Furthermore, to support the experimental results, a series of finite difference effective-stress analyses are performed in the prototype scale. The mitigation results show that the deformable panels can significantly decrease the seaward movement, settlement and inclination of wall as well as the total pressure recorded behind the caisson wall. Here, these panels are called Displacement Reducer Panels (DRP) based on the obtained results.
S N Jonkman - One of the best experts on this subject based on the ideXlab platform.
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time dependent reliability analysis of service proven Quay Walls subject to corrosion induced degradation
Reliability Engineering & System Safety, 2020Co-Authors: A.a. Roubos, T Schweckendiek, Raphael D J M Steenbergen, Diego L Allaix, S N JonkmanAbstract:Abstract The assessment of service-proven Quay Walls subject to corrosion-induced degradation is inherently a time-dependent reliability problem. Two major challenges are the modelling of corrosion and taking into account the decrease of epistemic uncertainty throughout the Quay wall's service life. The main objective of this study is to examine the probability of failure, despite successful past performance, when the Quay wall is subject to corrosion and randomly imposed variable loads. The development of the annual failure rate is modelled using crude Monte Carlo and by performing a first-order system reliability analysis. The annual failure rates found for service-proven Quay Walls vary over time. For those with successful service histories and subject to low corrosion rates, the highest reliability indices are observed in the first year of the service life, whereas with higher corrosion rates the final year prevails. In general, it seems more practical to evaluate reliability on an annual basis rather than over longer time periods, since the latter will introduce an iterative procedure to determine the wall's remaining lifetime. The key findings of this study can be crucial for the lifetime extension of existing Quay Walls, and presumably also for other service-proven geotechnical structures subject to corrosion.
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finite element based reliability assessment of Quay Walls
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 2020Co-Authors: A.a. Roubos, T Schweckendiek, R B J Brinkgreve, Raphael D J M Steenbergen, S N JonkmanAbstract:While reliability methods have already been widely adopted in civil engineering, the efficiency and robustness of finite element-based reliability assessments of Quay Walls are still fairly low. In...
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target reliability indices for existing Quay Walls derived on the basis of the lqi criterion
R.Taerwe L. frangopol d.m.caspeele Life-Cycle Analysis and Assessment in Civil Engineering: Towards an Integrated Vision - Proceedings of the 6th Inte, 2019Co-Authors: A.a. Roubos, Raphael D J M Steenbergen, Diego L Allaix, K Fischer, S N JonkmanAbstract:General frameworks for reliability differentiation have evolved over time and are mainly developed for new buildings. However, recommendations for existing Quay Walls are lacking. In this study target reliability indices for assessing existing Quay Walls were derived by economic optimisation and by evaluating the Life Quality Index criterion (LQI). In Quay wall design, some dominant stochastic design variables are largely time-independent, such as soil and material properties. The influence of time-independent variables on the development of the probability of failure was taken into consideration in this study, because this affects the present value of future failure costs and the associated target reliability indices. The reliability indices obtained in accordance with the LQI acceptance criterion were a little lower than the target reliability indices derived by economic optimization. The target reliability indices obtained for existing Quay Walls depend on the consequences of failure and the remaining service life. If failure modes of a Quay wall are largely time-invariant and already survived the first period of the service life, the residual probability of failure is lower for an existing Quay wall compared to a new Quay wall. Hence, this should be considered in the determination of target reliability indices. The method of approach to assess the development of reliability over time can also be used for evaluating target reliability indices of other civil and geotechnical structures. © 2019 Taylor & Francis Group, London.
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Risk-based target reliability indices for Quay Walls
Structural Safety, 2018Co-Authors: A.a. Roubos, T Schweckendiek, Raphael D J M Steenbergen, S N JonkmanAbstract:Design codes and standards rely on generalised target reliability indices. It is unclear, however, whether these indices are applicable to the specific risk-profile of marine structures. In this study, target reliability indices for Quay Walls were derived from various risk acceptance criteria, such as economic optimisation, individual risk (IR), societal risk (SR), the life quality index (LQI) and the social and environmental repercussion index (SERI). Important stochastic design variables in Quay wall design, such as retaining height, soil strength and material properties, are largely time-independent, whereas other design variables are time-dependent. The extent to which a reliability problem is time variant affects the present value of future failure costs and the associated reliability optimum. A method was therefore developed to determine the influence of time-independent variables on the development of failure probability over time. This method can also be used to evaluate target reliability indices of other civil and geotechnical structures. The target reliability indices obtained for Quay Walls depend on failure consequences and marginal costs of safety investments. The results were used to elaborate the reliability framework of ISO 2394, and associated reliability levels are proposed for various consequence classes. The insights acquired were used to evaluate the acceptable probability of failure for different types of Quay Walls.
Raphael D J M Steenbergen - One of the best experts on this subject based on the ideXlab platform.
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time dependent reliability analysis of service proven Quay Walls subject to corrosion induced degradation
Reliability Engineering & System Safety, 2020Co-Authors: A.a. Roubos, T Schweckendiek, Raphael D J M Steenbergen, Diego L Allaix, S N JonkmanAbstract:Abstract The assessment of service-proven Quay Walls subject to corrosion-induced degradation is inherently a time-dependent reliability problem. Two major challenges are the modelling of corrosion and taking into account the decrease of epistemic uncertainty throughout the Quay wall's service life. The main objective of this study is to examine the probability of failure, despite successful past performance, when the Quay wall is subject to corrosion and randomly imposed variable loads. The development of the annual failure rate is modelled using crude Monte Carlo and by performing a first-order system reliability analysis. The annual failure rates found for service-proven Quay Walls vary over time. For those with successful service histories and subject to low corrosion rates, the highest reliability indices are observed in the first year of the service life, whereas with higher corrosion rates the final year prevails. In general, it seems more practical to evaluate reliability on an annual basis rather than over longer time periods, since the latter will introduce an iterative procedure to determine the wall's remaining lifetime. The key findings of this study can be crucial for the lifetime extension of existing Quay Walls, and presumably also for other service-proven geotechnical structures subject to corrosion.
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finite element based reliability assessment of Quay Walls
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 2020Co-Authors: A.a. Roubos, T Schweckendiek, R B J Brinkgreve, Raphael D J M Steenbergen, S N JonkmanAbstract:While reliability methods have already been widely adopted in civil engineering, the efficiency and robustness of finite element-based reliability assessments of Quay Walls are still fairly low. In...
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target reliability indices for existing Quay Walls derived on the basis of economic optimisation and human safety requirements
Structure and Infrastructure Engineering, 2020Co-Authors: A.a. Roubos, Raphael D J M Steenbergen, Diego L Allaix, K Fischer, S N JonkmanAbstract:General frameworks for reliability differentiation have evolved over time and are mainly developed for buildings. However, recommendations for the safety of existing Quay Walls are lacking. In this study, target reliability indices for assessing existing Quay Walls were derived by economic optimisation and by evaluating the requirements concerning human safety. In Quay-wall design, some dominant stochastic design variables are largely time-independent, such as soil and material properties. The influence of time-independent variables on the evolution of the probability of failure was taken into consideration, since this affects the present value of future failure costs and the associated target reliability indices. The target reliability indices obtained for existing Quay Walls depend on the consequences of failure and the remaining lifetime. If the failure modes of a Quay wall are governed by time-independent design parameters and the Quay wall has already survived the early service period, the residual probability of failure is lower for an existing Quay wall compared to a new structure. Hence, this should be considered in the determination of target reliability indices. The method to evaluate Quay-wall reliability over time can also be used to assess other civil and geotechnical structures.
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target reliability indices for Quay Walls jetties and flexible dolphins
Ports 2019, 2019Co-Authors: A.a. Roubos, Dirk Jan Peters, Raphael D J M SteenbergenAbstract:Structural codes rely on generalised target reliability indices, which are mainly derived for buildings. It is unclear, however, whether these indices are applicable to the specific risk-profile of Quay Walls, jetties, and flexible dolphins. In this study, target reliability indices for marine structures were derived from various risk acceptance criteria, such as economic optimisation, individual risk, societal risk, the life quality index, and the social and environmental repercussion index. This article uses a method to determine reliability targets distinguishing time-dependent and time-independent variables, because some important stochastic design variables in the design of marine structures, such as soil and material properties, are largely time-independent. The assessment framework of ISO 2394, taking into account social, economic, and environmental impact, has proven to be a solid basis for reliability differentiation. The method of approach considered in this paper can also be used for evaluating target reliability indices of other geotechnical structures.
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target reliability indices for existing Quay Walls derived on the basis of the lqi criterion
R.Taerwe L. frangopol d.m.caspeele Life-Cycle Analysis and Assessment in Civil Engineering: Towards an Integrated Vision - Proceedings of the 6th Inte, 2019Co-Authors: A.a. Roubos, Raphael D J M Steenbergen, Diego L Allaix, K Fischer, S N JonkmanAbstract:General frameworks for reliability differentiation have evolved over time and are mainly developed for new buildings. However, recommendations for existing Quay Walls are lacking. In this study target reliability indices for assessing existing Quay Walls were derived by economic optimisation and by evaluating the Life Quality Index criterion (LQI). In Quay wall design, some dominant stochastic design variables are largely time-independent, such as soil and material properties. The influence of time-independent variables on the development of the probability of failure was taken into consideration in this study, because this affects the present value of future failure costs and the associated target reliability indices. The reliability indices obtained in accordance with the LQI acceptance criterion were a little lower than the target reliability indices derived by economic optimization. The target reliability indices obtained for existing Quay Walls depend on the consequences of failure and the remaining service life. If failure modes of a Quay wall are largely time-invariant and already survived the first period of the service life, the residual probability of failure is lower for an existing Quay wall compared to a new Quay wall. Hence, this should be considered in the determination of target reliability indices. The method of approach to assess the development of reliability over time can also be used for evaluating target reliability indices of other civil and geotechnical structures. © 2019 Taylor & Francis Group, London.
