• Smart Structures and Systems
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• v.26 no.5
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• pp.591-603
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• 2020

Dynamic deflection monitoring is an essential and critical part of structural health monitoring for high-speed railway bridges. Two critical problems need to be addressed when using inclinometer sensors for such applications. These include constructing a general representation model of inclination-deflection and addressing the ill-posed inverse problem to obtain the accurate dynamic deflection. This paper provides a dynamic deflection monitoring method with the placement of optimal inclinometer sensors for high-speed railway bridges. The deflection shapes are reconstructed using the inclination-deflection transformation model based on the differential relationship between the inclination and displacement mode shape matrix. The proposed optimal sensor configuration can be used to select inclination-deflection transformation models that meet the required accuracy and stability from all possible sensor locations. In this study, the condition number and information entropy are employed to measure the ill-condition of the selected mode shape matrix and evaluate the prediction performance of different sensor configurations. The particle swarm optimization algorithm, genetic algorithm, and artificial fish swarm algorithm are used to optimize the sensor position placement. Numerical simulation and experimental validation results of a 5-span high-speed railway bridge show that the reconstructed deflection shapes agree well with those of the real bridge.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.191-198
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• 2003

The pavement stiffness is scarcely used in structural analysis to design the superstructure of bridge. It is reasonable not to consider it in the case of asphalt concrete pavement over concrete deck because the pavement stiffness compared with the concrete deck plate can be ignored. However, sometimes, the pavement materials have a similar amount of elastic modulus to concrete and are applied to the orthotropic steel deck plate which has relatively less stiffness compared with the concrete deck plate. In this paper, the steel plate deck of a real bridge project was analyzed by considering the pavement stiffness by linear elastic FEM. It was assumed that a perfect bond between the steel plate deck and the pavement exited. The results indicated that the structural behavior of the orthotropic steel deck plate can be estimated enough to affect the evaluation result of structural capacity in some cases. Therefore, the investigations by experimental tests and more advanced numerical model are indispensible in figuring the design formula for considering the effects of pavement stiffness in the structural analysis of an orthotropic bridge.

• Smart Structures and Systems
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• v.6 no.3
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• pp.309-333
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• 2010

Civil infrastructure, in both its construction and maintenance, represents the largest societal investment in this country, outside of the health care industry. Despite being the lifeline of US commerce, civil infrastructure has scarcely benefited from the latest sensor technological advances. Our future should focus on harnessing these technologies to enhance the robustness, longevity and economic viability of this vast, societal investment, in light of inherent uncertainties and their exposure to service and even extreme loadings. One of the principal means of insuring the robustness and longevity of infrastructure is to strategically deploy smart sensors in them. Therefore, the objective is to develop novel, durable, smart sensors that are especially applicable to major infrastructure and the facilities to validate their reliability and long-term functionality. In some cases, this implies the development of new sensing elements themselves, while in other cases involves innovative packaging and use of existing sensor technologies. In either case, a parallel focus will be the integration and networking of these smart sensing elements for reliable data acquisition, transmission, and fusion, within a decision-making framework targeting efficient management and maintenance of infrastructure systems. In this paper, prudent and viable sensor and health monitoring technologies have been developed and used in several large structural systems. Discussion will also include several practical bridge health monitoring applications including their design, construction, and operation of the systems.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.1-8
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• 2009

The proposed real-time structural health monitoring(SHM) system in past transferred and received data, central server gathered data from sensors, through coaxial cable. an immense sum of money is required to structure sensor network using coaxial cable. This paper proposes USN-based structural health monitoring(SHM). AIso, this paper designs and realizes prototypes according to proposed SHM. The value of sensing data obtained through HSDPA transfer to the BMS(Bridge Monitoring Server) passing through the TCP / IP socket by building two-way communication system, We have implemented a complete graph converting full system.

• Water Engineering Research
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• v.7 no.1
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• pp.21-28
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• 2006

The scouring process is complex and subject to many factors. Recently, experiments for real-time bridge scour monitoring have been active as means for a more reliable scour prediction. Riverbed materials are an important factor in bridge scouring; therefore, an accurate estimation of riverbed material is critical in predicting a scour. As a part of this approach, an ultrasonic sensor, which can not only detect river bottom during floods but can also be installed lose to the underwater structures, was developed. This sensor is able to map the river bottom using an ultrasonic waves with the characteristics of the returning wave, reflected from an object or bottom ground. The reflected wave is unique according to the situations, or materials below. Therefore, it would be possible to identify the consisting materials of a riverbed if we could reveal each characteristic in the received signals. In this study, a preliminary experiment was performed in the laboratory to identify and classify received signals, which is unique to each material. The analysis of this experiment gives the graph, which makes it possible to identify materials of the river bottom through the ultrasonic signals. The proposed graph was verified through a comparison with the actual field data measured in river.

• Steel and Composite Structures
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• v.33 no.4
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• pp.537-550
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• 2019

Korea and Japan have done a lot of research on composite girders with corrugated steel webs and built many bridges with corrugated steel webs due to the significant advantages of this type of bridges. Considering the demanding on the calculation method of such types of bridges and lack of relevant reinforcement design method, this paper proposes the spatial grid analysis theory and tensile stress region method. First, the accuracy and applicability of spatial grid model in analyzing composite girders with corrugated steel webs was validated by the comparison with models using shell and solid elements. Then, in a real engineering practice, the reinforcement designs from tensile stress region method based on spatial grid model, design empirical method and specification method are compared. The results show that the tensile stress region reinforcement design method can realize the inplane and out-of-plane reinforcement design in the top and bottom slabs in bridges with corrugated steel webs. The economy and precision of reinforcement design using the tensile stress region method is emphasized. Therefore, the tensile stress region reinforcement design method based on the spatial grid model can provide a new direction for the refined design of composite box girder with corrugated steel webs.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.606-615
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• 2009

Estimating the reasonable construction-cost according to the construction phase in public construction is an important element for securing and executing a national budget efficiently. As a general rule, the predetermined cost of construction is estimated at the end of the design of the target structure. Therefore, it seems to be a considerably difficult problem to estimate the approximate cost of construction, only with its basic information of the bridge in the design planning phase and the early design stage where we can not have specific detailed-section of the target structure. In this paper, we present the calculation of construction-cost in the planning phase based on the analysis of factors affecting the cost of construction conducted in the previous study. Beside, to estimate the cost of construction in early design phase, we would like to present the calculation of construction-cost in the early design phase by executing the analysis of data collected from 61 steel box bridges. It was found from the result of study that the estimated cost of construction gained by the calculation of construction-cost in this paper reduces the error between the real cost of construction and that by the existing method of using.

• Structural Monitoring and Maintenance
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• v.10 no.2
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• pp.107-116
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• 2023

The health condition of of deep water high pile foundation is vital to the safe operation of bridges. However, pier foundations are vulnerable to damage in deep water due to exposure to sea torrents and corrosive environments over an extended period. In this paper, combined with aninvestigation and analysis of the typical damage characteristics of main pier group pile foundations, we study the safety monitoring and real-time early warning technology of the deep water high pile foundations, we propose an early warning index item and early warning threshold of deep water high pile foundation by utilizing a numerical simulation analysis and referring to domestic and foreign standards and literature. First, we combine the characteristics of structures and draw on more mature evaluation theories and experience in civil engineering-related fields such as dam and bridge engineering. Then, we establish a scheme consisting of a Early Warning Index Systemand evaluation model based on the analytic hierarchy process and constant weight evaluation method and apply the research results to a project based on the Jiashao bridge in Zhejiang province, China. Finally, we verify the rationality and reliability of the Early Warning Index Systemof the Deep Water High Pile Foundations.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.689-694
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• 2006

Wireless LAN is getting more popularity and plays a main role in electronic and telecommunication field. Wireless LAN is more convenient than wired LAN when mobility is required, and are sometimes the only feasible choice. Wireless LAN can also pose a significant security risk when not properly installed and maintained. Thus, this paper studies real-time message transmission using existing mobile telecommunication network and describes considerations and procedures when introducing wireless LAN concept and wireless LAN systems. It also studies integrated wired and wireless networking including wireless LAN bridge and AP technology of International Organization for Standardization, and especially real-time dynamic image data transmission in a moving train.

• Journal of the Korea Concrete Institute
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• v.26 no.1
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• pp.3-12
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• 2014

Hybrid Truss Bridge (HTB) uses steel truss webs instead of concrete webs in prestressed box girder bridges, which is becoming popular due to its structural benefits such as relatively light self-weight and good aesthetics appearance. Since the core technology of this bridge is the connection system between concrete slabs and steel truss members, several connection systems were proposed and experimentally evaluated. Also, the selected joint system was applied to the real bride design and construction. The research was performed on the connection system, since it can affect the global behavior of this bridge such as flexural and fatigue behaviors as well as the local behavior around the connection region. The evaluation study showed that HTB applied to a curved bridge or an eccentrically loaded bridge had a weak torsional capacity compared to an ordinary PSC box girder bridge due to the open cross-sectional characteristic of HTB. Therefore, three types of girders with different joint system between truss web member and concrete slab were tested for their torsional capacity. In this study, the three different types of HTB girders under torsional loading were simulated using FEM analysis to investigate the torsional behavior of HTB girders more in detail. The results are discussed in detail in the paper.