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Zhihong Fan - One of the best experts on this subject based on the ideXlab platform.
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Durability for concrete structures in marine environments of HZM project: Design, assessment and beyond
Cement and Concrete Research, 2019Co-Authors: Dongdong Zhang, Zhihong FanAbstract:Abstract This paper reviews the fundamentals of the Durability of structural concrete, and then applies the concepts to the Durability Design, quality control, performance assessment and maintenance planning of concrete structures in Hong Kong-Zhuhai-Macau (HZM) sea link project with Design working life of 120 years. The Durability Design adopts a multi-level philosophy for different Durability risks and uses model-based approach to determine Design parameters. The long-term exposure data of 30 years were used to calibrate the chloride ingress model and quantify the modelling uncertainty. The Durability quality control was realized through converting the Design values to laboratory characterization values, especially for the chloride diffusivity. With the data collected in construction phase, a full-probabilistic assessment is performed on the achieved performance against the chloride ingress, serving as basis for maintenance planning. The open issues related to the Durability of concrete infrastructures with long service life are elaborated in the end.
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Durability Design of the hong kong zhuhai macau sea link project principle and procedure
Journal of Bridge Engineering, 2015Co-Authors: Xingang Zhou, Zhihong FanAbstract:AbstractThis paper introduces the Durability Design of concrete structures in the Hong Kong–Zhuhai–Macau project for a working life of 120 years. The environmental actions are analyzed and the deterioration processes for the structural concrete are identified. The Durability Design is performed through material composition control and a performance-based procedure. The target Design lives and Durability limit states are attributed to concrete elements according to their structural importance and maintenanceability. Given the prescriptive requirements on material compositions, the carbonation-induced and chloride-induced corrosions of reinforcement steel are considered as the most critical processes and subject to model-based Design. The thickness and quality of concrete covers are determined from carbonation and chloride penetration models using a partial factor scheme. For chloride ingress, the partial factors are calibrated from a full probabilistic approach for a target reliability β=1.3. The statistic...
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Model-based Durability Design of concrete structures in Hong Kong-Zhuhai-Macau sea link project
Structural Safety, 2015Co-Authors: Xin’gang Zhou, Qinming Zhang, Zhihong FanAbstract:Abstract This paper presents the Durability Design of concrete structures in the Hong Kong–Zhuhai–Macau (HZM) sea link project for a Design service life of 120 years. Among all the Durability issues, this paper focuses on the model-based Durability Design of concrete structures in the project subject to the action of marine chlorides. The mechanism and modeling of chloride penetration into concrete are reviewed in depth and the applicability of models for Durability Design is evaluated. On the basis of long-term exposure tests and in-place structural investigations during the past 30 years in South-eastern China, the Design model for concrete structures in the HZM project is established. The statistical properties of model parameters are analyzed in details and compared to other chloride ingress models. Using the established HZM model for chloride ingress and specified Durability limit state (DLS), the Design parameters are first evaluated through a fully probabilistic analysis in terms of service lives (50 years, 120 years) and target reliability levels ( β = 1.3, 1.5, 1.8). The partial factor format for Durability Design is then established and the partial factors are calibrated from the first order reliability method (FORM) from specified service life and specified reliability level. The Design results from the partial factor Design equation are given for different exposure zones, and the achieved reliability index is verified for each Design through the full probabilistic method. Finally remarks are given on the HZM model and its application in Durability Design of RC elements.
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Durability Design of the Hong Kong–Zhuhai–Macau Sea-Link Project: Principle and Procedure
Journal of Bridge Engineering, 2015Co-Authors: Xin’gang Zhou, Zhihong FanAbstract:AbstractThis paper introduces the Durability Design of concrete structures in the Hong Kong–Zhuhai–Macau project for a working life of 120 years. The environmental actions are analyzed and the deterioration processes for the structural concrete are identified. The Durability Design is performed through material composition control and a performance-based procedure. The target Design lives and Durability limit states are attributed to concrete elements according to their structural importance and maintenanceability. Given the prescriptive requirements on material compositions, the carbonation-induced and chloride-induced corrosions of reinforcement steel are considered as the most critical processes and subject to model-based Design. The thickness and quality of concrete covers are determined from carbonation and chloride penetration models using a partial factor scheme. For chloride ingress, the partial factors are calibrated from a full probabilistic approach for a target reliability β=1.3. The statistic...
Xin’gang Zhou - One of the best experts on this subject based on the ideXlab platform.
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Durability Design of the Hong Kong–Zhuhai–Macau Sea-Link Project: Principle and Procedure
Journal of Bridge Engineering, 2015Co-Authors: Xin’gang Zhou, Zhihong FanAbstract:AbstractThis paper introduces the Durability Design of concrete structures in the Hong Kong–Zhuhai–Macau project for a working life of 120 years. The environmental actions are analyzed and the deterioration processes for the structural concrete are identified. The Durability Design is performed through material composition control and a performance-based procedure. The target Design lives and Durability limit states are attributed to concrete elements according to their structural importance and maintenanceability. Given the prescriptive requirements on material compositions, the carbonation-induced and chloride-induced corrosions of reinforcement steel are considered as the most critical processes and subject to model-based Design. The thickness and quality of concrete covers are determined from carbonation and chloride penetration models using a partial factor scheme. For chloride ingress, the partial factors are calibrated from a full probabilistic approach for a target reliability β=1.3. The statistic...
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Model-based Durability Design of concrete structures in Hong Kong-Zhuhai-Macau sea link project
Structural Safety, 2015Co-Authors: Xin’gang Zhou, Qinming Zhang, Zhihong FanAbstract:Abstract This paper presents the Durability Design of concrete structures in the Hong Kong–Zhuhai–Macau (HZM) sea link project for a Design service life of 120 years. Among all the Durability issues, this paper focuses on the model-based Durability Design of concrete structures in the project subject to the action of marine chlorides. The mechanism and modeling of chloride penetration into concrete are reviewed in depth and the applicability of models for Durability Design is evaluated. On the basis of long-term exposure tests and in-place structural investigations during the past 30 years in South-eastern China, the Design model for concrete structures in the HZM project is established. The statistical properties of model parameters are analyzed in details and compared to other chloride ingress models. Using the established HZM model for chloride ingress and specified Durability limit state (DLS), the Design parameters are first evaluated through a fully probabilistic analysis in terms of service lives (50 years, 120 years) and target reliability levels ( β = 1.3, 1.5, 1.8). The partial factor format for Durability Design is then established and the partial factors are calibrated from the first order reliability method (FORM) from specified service life and specified reliability level. The Design results from the partial factor Design equation are given for different exposure zones, and the achieved reliability index is verified for each Design through the full probabilistic method. Finally remarks are given on the HZM model and its application in Durability Design of RC elements.
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Sensitivity study on Durability variables of marine concrete structures
Journal of Marine Science and Application, 2013Co-Authors: Xin’gang Zhou, Kefei LiAbstract:In order to study the influence of parameters on Durability of marine concrete structures, the parameter's sensitivity analysis was studied in this paper. With the Fick's 2nd law of diffusion and the deterministic sensitivity analysis method (DSA), the sensitivity factors of apparent surface chloride content, apparent chloride diffusion coefficient and its time dependent attenuation factor were analyzed. The results of the analysis show that the impact of Design variables on concrete Durability was different. The values of sensitivity factor of chloride diffusion coefficient and its time dependent attenuation factor were higher than others. Relative less error in chloride diffusion coefficient and its time dependent attenuation coefficient induces a bigger error in concrete Durability Design and life prediction. According to probability sensitivity analysis (PSA), the influence of mean value and variance of concrete Durability Design variables on the Durability failure probability was studied. The results of the study provide quantitative measures of the importance of concrete Durability Design and life prediction variables. It was concluded that the chloride diffusion coefficient and its time dependent attenuation factor have more influence on the reliability of marine concrete structural Durability. In Durability Design and life prediction of marine concrete structures, it was very important to reduce the
Seung-jun Kwon - One of the best experts on this subject based on the ideXlab platform.
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Current Trends of Durability Design and Government Support in South Korea: Chloride Attack
Sustainability, 2017Co-Authors: Seung-jun KwonAbstract:Concrete is considered to be a construction material with high Durability and excellent fire resistance. However, degradation occurs, leading to structural safety problems and expensive maintenance costs. Currently, Durability Design and its concepts are provided in the concrete specifications and structural Design codes in many countries, but they vary in terms of the Design methodologies and users’ demands. Reinforced concrete (RC) structures based on a reasonable Durability Design with a quantitative procedure can prevent unnecessary maintenance expenses and reduce environmental loads. This paper presents the current trends of Durability Design in South Korea and government support for infrastructure. In this work, the two representative Durability Design philosophies (deterministic and probabilistic approaches) are briefly summarized, and the current guidelines and related requirements for Durability Design in several countries are investigated. Durability Design is now changing from simple material requirement control to performance-based Design with quantitative parameters considering various exposure classifications and evaluation processes. RC structures based on reasonable Durability Design can make a great contribution to reducing maintenance costs and environmental effects like CO2 emissions.
Odd E Gjorv - One of the best experts on this subject based on the ideXlab platform.
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Durability Design and sustainability of new major concrete infrastructure
Journal of Sustainable Cement-Based Materials, 2016Co-Authors: Odd E GjorvAbstract:Much of the observed Durability problems on concrete structures in severe environments can be ascribed due to lack of proper quality assurance during concrete construction and poorly achieved construction quality. Upon completion of new concrete structures, the achieved construction quality typically shows a high scatter and variability, and during operation of the structures, any weaknesses and deficiencies will soon be revealed whatever Durability specifications and materials have been applied. To a certain extent, a probability approach to the Durability Design can accommodate the high scatter and variability. However, a numerical approach alone is insufficient for ensuring the Durability; greater control and improvements in Durability also require the specification of performance-based Durability requirements which can be verified and controlled during concrete construction in order to achieve quality assurance. In the present paper, current experience with probability-based Durability Design and perf...
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Durability Design of new concrete infrastructure for future development of Singapore City
Marine Concrete Structures, 2016Co-Authors: Odd E GjorvAbstract:Abstract Singapore has an extremely limited land area; therefore, the creation of additional space has become an important strategic issue. In 2011, a 5-year research program at Nanyang Technological University in Singapore was started, the objective of which was to develop the technical basis for future space creation and development of the city based on a large number of offshore concrete structures extending from the seabed to above sea level. For such important concrete infrastructure, the highest possible Durability, reliability and service life would be of vital importance. As part of the research program, a proper basis for Durability Design of the concrete structures had to be established, and for this, the probability-based DURACON Model was adopted. To provide a certain basis for selecting proper combinations of concrete quality based on constituent materials locally available and concrete cover that would give the highest possible Durability of the future concrete structures, an experimental program was also undertaken. In the present chapter, the basis for the Durability Design is briefly outlined and discussed. A brief outline of the experimental investigations is also given, selected results from which are used as input to some Durability analyses to demonstrate how future concrete structures with a very low corrosion probability for exposure to the given environment could be produced.
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Durability Design of Concrete Structures in Severe Environments, Second Edition - Durability Design of Concrete Structures in Severe Environments, Second Edition
2014Co-Authors: Odd E GjorvAbstract:The deterioration of major concrete infrastructure in marine and other chloride-containing environments is a major problem facing the construction industry around the world. The book describes field experiences and deteriorating processes of concrete structures in severe environments and includes current data on extensive field tests. The book presents a Durability Design based on the calculation of corrosion probability and outlines additional protective strategies and measures. The procedures for performance-based concrete quality control and quality assurance with documentation of achieved construction quality and compliance with specified Durability are one of the main focuses. The book also covers the calculation of life cycle costs and life cycle assessment and includes some new recommended job specifications. While recent advancements in concrete technology have made it easier to control the negative impact of deteriorating processes such as alkali-aggregate reaction, freezing and thawing and chemical attack, chloride-induced corrosion of embedded steel continues to pose the biggest threat to structure Durability and performance. The book focuses on enhancing the Durability and service life of concrete structures and delivers more results and experiences from practical applications of the probability-based Durability Design and performance-based concrete quality control. The book includes information on recent commercial projects both for Oslo Harbor KF and Nye Tjuvholmen KS in Oslo.
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Durability Design of concrete structures in severe environments second edition
2014Co-Authors: Odd E GjorvAbstract:The deterioration of major concrete infrastructure in marine and other chloride-containing environments is a major problem facing the construction industry around the world. The book describes field experiences and deteriorating processes of concrete structures in severe environments and includes current data on extensive field tests. The book presents a Durability Design based on the calculation of corrosion probability and outlines additional protective strategies and measures. The procedures for performance-based concrete quality control and quality assurance with documentation of achieved construction quality and compliance with specified Durability are one of the main focuses. The book also covers the calculation of life cycle costs and life cycle assessment and includes some new recommended job specifications. While recent advancements in concrete technology have made it easier to control the negative impact of deteriorating processes such as alkali-aggregate reaction, freezing and thawing and chemical attack, chloride-induced corrosion of embedded steel continues to pose the biggest threat to structure Durability and performance. The book focuses on enhancing the Durability and service life of concrete structures and delivers more results and experiences from practical applications of the probability-based Durability Design and performance-based concrete quality control. The book includes information on recent commercial projects both for Oslo Harbor KF and Nye Tjuvholmen KS in Oslo.
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Durability Design and quality assurance of major concrete infrastructure
Advances in Concrete Construction, 2013Co-Authors: Odd E GjorvAbstract:Upon completion of new concrete structures, the achieved construction quality always shows a high scatter and variability, and in severe environments, any weaknesses and deficiencies will soon be revealed whatever Durability specifications and materials have been applied. To a certain extent, a probability approach to the Durability Design can take the high scatter and variability into account. However, numerical solutions alone are not sufficient to ensure the Durability and service life of concrete structures in severe environments. In the present paper, the basis for a probability-based Durability Design is briefly outlined and discussed. As a result, some performance-based Durability requirements are specified which are used for quality control and quality assurance during concrete construction. The final documentation of achieved construction quality and compliance with the specified Durability are key to any rational approach to more controlled and increased Durability. As part of the Durability Design, a service manual for future condition assessment and preventive maintenance of the structure is also produced. It is such a service manual which helps provide the ultimate basis for achieving a more controlled Durability and service life of the given concrete structure in the given environment.
Mitsuyoshi Akiyama - One of the best experts on this subject based on the ideXlab platform.
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reliability based Durability Design and service life assessment of reinforced concrete deck slab of jetty structures
Structure and Infrastructure Engineering, 2017Co-Authors: Mitsuyoshi Akiyama, Dan M. Frangopol, Koshin TakenakaAbstract:AbstractReinforced concrete (RC) structures in a marine environment deteriorate with time due to chloride-induced corrosion of reinforcing bars. Since the RC deck slabs of jetty structures are exposed to a very aggressive environment, higher deterioration rates can develop. In this paper, a reliability-based Durability Design and service life assessment of RC jetty structures are presented. For new RC jetty structures, the concrete quality and concrete cover necessary to prevent the chloride-induced reinforcement corrosion causing the deterioration of structural performance during the whole lifetime could be determined. Based on the airborne chloride hazard depending on the vertical distance from the sea level surface to the RC deck slab, the probability associated with the steel corrosion initiation is estimated. The water to cement ratio and concrete cover to satisfy the target reliability level are provided. For evaluating the service life of existing structures, the condition state based on the visual...
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integration of the effects of airborne chlorides into reliability based Durability Design of reinforced concrete structures in a marine environment
Structure and Infrastructure Engineering, 2012Co-Authors: Mitsuyoshi Akiyama, Dan M. Frangopol, Motoyuki SuzukiAbstract:In this paper, the hazard curve associated with airborne chlorides in a marine environment and the computational procedure to obtain the probability of occurrence of corrosion cracking in reinforced concrete (RC) structures are presented. A method for integration of the effects of airborne chloride into reliability-based Durability Design of RC structures in a marine environment is proposed. By using this method, it is possible to determine the probability of corrosion cracking due to airborne chlorides, regardless of region, distance from coastline, and the properties of the concrete controlled by the water to cement ratio.
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MAXIMUM AMOUNT OF REINFORCING BAR CORROSION AND RELIABILITY-BASED Durability Design TO ENSURE THE SEISMIC SAFETY OF RC BRIDGE PIERS EXPOSED TO MARINE ENVIRONMENT
Doboku Gakkai Ronbunshuu E, 2008Co-Authors: Mitsuyoshi Akiyama, Hiroshi Matsuzaki, Hirokazu Sato, Hideki Naito, Motoyuki SuzukiAbstract:Although accurate structural models of corroded structures subjected to monotonic flexure and/or shear have been developed, few seismic performance studies consider corrosion damage. Earthquakes are a dominant hazard to structures in many parts of the world. Lifetime assessments of structures in aggressive environments and earthquake prone regions must consider the effects of corrosion on seismic performance. While the seismic demand depends on the results of the seismic hazard assessment, the deterioration of seismic capacity depends on the environmental hazard assessment. This paper analyzes the life-cycle reliability of corroded reinforced concrete structures under earthquake excitations and presents a reliability-based Durability Design methodology that ensures the seismic safety of RC bridge piers in a marine environment.
