Durability assessment and re-design of massive concrete structures in sea-linking projects

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This paper presents a method for the durability assessment and re-design of concrete structures in sea-linking projects, such as the Hong Kong-Zhuhai-Macau Bridge (HZMB) project. In order to assess the durability condition of the reinforced concrete structures associated with the chloride-induced corrosion of steel in concrete, data sets obtained from construction, managing, monitoring and exposure sites are used to build a durability assessment model to predict when the depassivation of steel will happen, when necessary repair methods need to be taken and to put forward an assessment method of the durability of the structures with a failure probability. With different levels of failure probability obtained, different methods of strengthening and renovation can be adopted to improve the durability of the concrete structures and make sure the target service life can be achieved.

Digital transformation of bridges inspection, monitoring and maintenance processes

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New communication and information systems and technologies ? known as ICT (Information and Communication Technologies) ? have immense potential to aggregate new functionalities and services to the management of infrastructure assets. This phenomenon, known as 'Digital Transformation', has influenced the evolution of various sectors of our society, such as the emergence of 'Industry 4.0'. New wireless communication technologies, such as 5G networks (large capacity communication, high reliability, great coverage and low consumption, for information processing and management ? such as Cloud Computing, Edge Computing, Big Data, Machine Learning and Artificial Intelligence ? are considered as the enabling technologies of this digital transformation, integrated with the concept of IoT(Internet of Things). High connectivity capacity and intensive automation enable, for example, changes in inspection paradigms and asset maintenance by transferring product focus to service platforms ('Everything' as a Service ? XaaS), bringing gains for efficiency, productivity, comfort and operational safety, as well as cost reduction. Bridges constitute an important part of the infrastructure and are subjected to damage caused by their continuous use over time. In addition to the effects of loading (fatigue, impacts, overloads, etc.), they are subjected to degradation of materials and support conditions, as well as exposure to adverse environmental conditions (storms, floods, gale, earthquakes, etc.). Scheduled inspections to assess their structural conditions are essential to ensure their proper use within the established safety limits. In other occasions, continuous or repeated monitoring of structural responses of bridges (displacements, vibrations and rotations at critical points) may add important information for decision-making regarding its maintenance, repair and reinforcement. The use of these data, together with techniques of structural reliability for the treatment of the uncertainties, allows predictions about the structural behavior to be elaborated with the consideration of different loading and degradation scenarios. The new ICTs can greatly contribute to the improvement of maintenance capacity and, consequently, to the reliability of the assets and to the operational availability of the system. Thus, the development of new predictive maintenance approaches, which make use of the large amount of data available, can improve the efficiency of maintenance processes, producing more accurate and reliable anticipated diagnostics. In this way, Digital Transformation can reduce maintenance costs (avoiding unnecessary maintenance events) and improve system availability, reducing operational losses. The use of Big Data Analytics, incorporating Artificial Intelligence and Machine Learning, are innovative solutions that can be introduced. The adoption of Digital Twins, that incorporate all these tools, can lead to a reduction in the total cost, allowing predictive and proactive maintenance. The concept of a Digital Twin for a railway bridge will be illustrated in this paper.

How to design, construct, and maintain highly-durable concrete bridges in cold and local regions

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In Japan, reinforced concrete deck slabs of major road bridges in cold regions have suffered from rapid aging due to the large-scale use of de-icing agent (NaCl). Additionally, a large number of minor bridges in farming and other local regions are facing lack of financial and technological resources for maintenance. In this paper, some methodologies to design, construct, and maintain highly-durable concrete bridges in cold and local regions are introduced. Firstly, six full size RC deck slabs on steel main girders were reproduced in the university campus. Varying the materials and mixture proportions, and construction methods for each slab, the performance was evaluated. The test and evaluation results were effective to develop highly-durable concrete deck slabs having excellent durability and crack resistance even under harsh chloride environment. Then, the developed deck slab based on the multiple protection strategy has been applied to reconstruction roads in the 2011 Tohoku earthquake-damaged regions. On the other hand, to maintain infrastructures by a simple preventive method, the spirit of fushin, is a starting point for civil engineering in Japan, is deeply ingrained in local regions. The concept of fushin is “the infrastructure desired by local residents should be built and maintained by themselves.” The latter part of this paper covers a modern-day version of this traditional maintenance method that has been introduced to local communities and put into practice.

Development of the requirements to major infrastructure projects

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This presentation will describe how the Road Directorate works with the development and exe-cution of construction of large infrastructure projects. The presentation will be divided into two parts, respectively, the framework for reducing climate and environmental impact and the challenge of norms and standards respectively; some illustrated by examples. In the planning phase, implementation of how the project best can contribute to meeting society's need for mobility must be implemented, which is often regarded as a prerequisite for economic growth and human well-being. The planning must include the latest knowledge on climate and environmental impact associated with the infrastructure life from cradle to grave and add knowledge that can form the basis for decisions on a focused and cost-effective climate action. The planning also includes factors that determine how biodiversity can be maintained as well as other considerations for the surrounding environment, including protected nature and habitat areas. The presentation will include examples of the optimization of the design assumptions, considering the risks associated with the geotechnical conditions and relevant load conditions such as ice and ship impact. Examples will be taken from the new Roskilde Fjord Link and the coming road-and railway bridge crossing Storstrømmen.

Some lessons of more than 20 years of inspection, maintenance and rehabilitation of bridges in Spain

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Spain has implemented a Management System for bridges belonging to the national road net-work since 1998. Since 1999, IDEAM has carried out for the Spanish public administrations more than 8,000 principal inspections; 150 specialized inspections; 200 structural damage evaluation reports; 200 repair and strengthening projects and 150 drafts of maintenance plans for structures. In most cases, the pathologies detected derive from construction failures or deficiencies in the conception of some details that could have been easily remedied or even anticipated, namely: drainage and waterproofing; duct grouting in post-tensioned concrete girders; internal corrosion of weathering steel box girder bridges; corbels; bearings; corrosion of tendons of stays belonging to the first cable-stayed bridges generation; problems arising from fatigue in steel bridges under increasing heavy traffic forces, etc. This lecture focuses on the description of some relevant practical case studies related to the afore mentioned topics.

Rising to the challenge of managing bridges in Australia

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Australia’s freight task is growing at a rapid rate due to unprecedented population growth, coupled with in-creased demand from our trading partners in Asia and rapid changes in technology, e-commerce and consumer behavior. A significant proportion of freight is transported using the road network and to remain competitive this network needs to facilitate fast, efficient and effective access. This is a significant challenge with an ageing bridge network, the regularly extreme climatic conditions and the freight industry constantly pushing to increase access and allowable loads.
In rising to this challenge, Australia’s infrastructure managers are being innovative, using the latest standards and technology in building new bridges and assessing existing bridges and utilizing the latest technology in managing existing bridge structures. In partnership with academic institutions and with funding from the State and Federal Governments, there has been significant research and development with the monitoring, modelling, assessment and strengthening of bridges.
This paper will outline what is currently being done to rise to this significant challenge and also recommend future research and development to continue to meet this challenge.

Rib-to-floor beam connections of orthotropic steel decks for bridge deck replacement applications

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Orthotropic steel decks (OSDs) are used for new bridge decks and replacement decks of highway bridges. An OSD includes various welded connections. This paper focuses on rib-to-floor beam (RFB) connections with emphasis on their fatigue performance. The bridge superstructure affects the fatigue stresses in RFB connections. Independent OSD floor beams that are not supported or restrained by other transverse members in the bridge are common for new bridge applications. Restrained OSD floor beams that are supported and re-strained by other transverse members in the bridge are common for deck replacement applications. When the OSD floor beam is supported by an existing transverse floor truss (or beam), the fatigue stresses at the RFB connection from in-plane loading are reduced. However, when the OSD floor beam is restrained by the existing floor truss, the fatigue stresses at the RFB connection from out-of-plane loading are increased. Thus, for deck replacement applications, a stress-relieving cut-out is often used in the OSD floor beam web to allow the ribs to rotate more freely under out-of-plane loading. An “extended cut-out” RFB connection has been used extensively in deck replacement applications in the US. The extended cut-out RFB connection often exhibits good fatigue performance, but this type of connection can be labor intensive to fabricate. This paper presents research on a new RFB connection for deck replacement applications with a “slit” cut-out completely within the OSD floor beam web that allows the rib to rotate, and is easier to fabricate than the extended cut-out RFB connection.

Energy-efficient autonomous framework for monitoring railroad bridges in the USA using wireless smart sensors

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One of the most critical components of the US transport system is railroads: providing means of transportation for 48% of the nation’s total modal tonnage. Despite such important tasks, more than half of the railroad bridges, the essential component of railroads to maintain flow of network, were built before 1920, making them the most fragile components of the railroad system. Wired and wireless sensor systems have been deployed, but none is designed specifically to address the challenges of railroad bridges monitoring, including: 1) limited energy source for sensors; 2) short and random nature of train schedule; 3) unavailable autonomous monitoring systems; and 4) difficult rapid decision-making process due to long data processing time. This paper focuses on efforts to develop an autonomous schedule-based framework for monitoring rail-road bridges using wireless smart sensor network (WSSN). This framework, which bases on WSSN platform Xnode, makes use of multiple components, including hardware, software, and algorithms to fulfill the needs for railroad bridge condition monitoring. To demonstrate the efficacy of this system, a full-scale monitoring campaign has been conducted. With these improvements to overcome the challenges of monitoring railroad bridges, this system is expected to become an important tool for railroad engineers and decision makers.

Why they call Chongqing the bridge capital of China?

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Why they call Chongqing the bridge capital of China? Here are the main reasons:
1. Bridge construction in Chongqing is most progressive; 2. Chongqing has most bridges in proportion to land area; 3. Chongqing has the most variety of bridges; 4. Bridges in Chongqing are more accessible; 5. People in Chongqing love their bridges; 6. Bridges in Chongqing are very beautiful!

Applications of AI, BIM, and sensing to bridge maintenance

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As a huge amount of structures built during the high economic growth period are approaching the end of their life, the extension of the longevity of bridges on a limited budget has become a crucial issue. Due to the retirement of a large number of maintenance engineers with expertise and lack of the young generation in this field, sustainability and knowledge transfer have become significant concerns. However, it is difficult to spend substantial money on infrastructure maintenance unlike construction. Therefore, advancing In-formation and Communication Technology (ICT) is expected to lead to smart bridge maintenance. This paper reviews the research on the applications of Artificial Intelligence (AI), Building Information Modeling (BIM), and sensing to bridge maintenance, discuss their effects and challenges, and consider future directions.