• Journal of the Society of Disaster Information
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• v.15 no.1
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• pp.28-38
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• 2019

Purpose: The purpose of this study is to contribute to improvement of measurement management level of construction structure and technology development of monitoring sensor by presenting the detailed causes and improvement plans of construction monitoring sensor's decline in durability. Method: The causes and improvement plans of the durability degradation of the construction monitoring sensor were divided into the construction field and the electric, electronic field. The detailed status was reviewed. Results: In the field of construction, approval and inspection, inspection and testing, verification and calibration, and minimization of loss and damage ratio were reviewed. In the field of electric and electronics, sensor package and sealing, disconnection of stress concentration area, damage caused by lightning and corrosion were reviewed. Conclusion: It is expected that the durability of monitoring sensors applied to the construction site will become longer than the present status based on the study that analyzed causes and improvement plans of construction monitoring sensor's decline in durability in the field of construction and electric, electronic devices.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.324-327
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• 2015

Scaffold is the most commonly used equipment in various types of construction works. Since various types of construction works use the same scaffold equipment, it becomes more difficult to be controlled and managed, thus resulting hazard frequently. According to the information announced in July 2012 by Council of Labor Affairs Executive Yan, the site collapse or incomplete anti-falling protection has led the site to accident frequently, and this is the main reason that causes construction industry occupational disasters. The labor death occupational hazard ratio rises up to 13% in scaffold activity, and the Council of Labor Affairs Executive Yan has showed that the death ratio is higher when using the scaffold in construction site, the total number of death has reached to 139 from 2005 to 2010. In order to ensure the safety of scaffold user, this study tends to build a wireless sensor monitoring system to detect the reliability and safety of the scaffold. The wireless sensor technique applies in this study is different with the traditional monitoring technique which is limited with wired monitoring. Wireless sensor technique does not need wire, it just needs to consider the power supply for establishing the network and receiving stable information, and it can become a monitoring system. In addition, this study also integrates strain gauge technique in this scaffold monitoring system, to develop a real-time monitoring data transfer mechanism and replace the traditional wired single project monitoring equipment. This study hopes to build a scaffold collapse monitoring system to effectively monitor the safety of the scaffold as well as provide the timesaving installation, low-cost and portable features.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.172-173
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• 2014

The study is used to verify the applicability of the sensor to monitor penetration of chloride into the concrete, like real coastal environment. After manufacturing the specimen adapt corrosion sensor for chloride penetration monitoring, chloride spray experiment was conducted. And then, It was checked the possibility of monitoring of the penetrated chloride by measuring the resistance of the corrosion sensor that was embedded in each depth of the concrete. Experimental results, it is confirmed that the corrosion resistance of the sensor was increased depending on the concentration of chloride. Therefore, it is estimated that the sensor is available for monitoring of chloride penetration.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.21-24
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• 2009

This study deals with the application of USN wireless inclinometer sensor for earth retaining structure safety measurement, The application of wireless inclinometer sensor has great advantage about real-time monitoring of earth retaining structure, It allows a construction manager to monitor movement data from anywhere connected through internet during the process of excavation for substructures of buildings, To validate the applicability of the wireless inclinometer sensor. laboratory and field tests have been performed, The results have shown that the measured values of wireless inclinometer sensor represent the behavior of H-pile well, Both convenience of sensor installation and real-time monitoring of earth retaining structure are confirmed, The proposed wireless measurement system provides a good basis for exact measurement of temporary substructures, More measurements and application are expected for the other excavation sites with various conditions.

• Structural Monitoring and Maintenance
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• v.5 no.2
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• pp.273-295
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• 2018

In this study, an investigation of a damage detection methodology for global condition assessment is presented. A particular emphasis is put on the utilization of wireless sensors for more practical, less time consuming, less expensive and safer monitoring and eventually maintenance purposes. Wireless sensors are deployed with a sensor roving technique to maintain a dense sensor field yet requiring fewer sensors. The time series analysis method called ARX models (Auto-Regressive models with eXogeneous input) for different sensor clusters is implemented for the exploration of artificially induced damage and their locations. The performance of the technique is verified by making use of the data sets acquired from a 4-span bridge-type steel structure in a controlled laboratory environment. In that, the free response vibration data of the structure for a specific sensor cluster is measured by both wired and wireless sensors and the acceleration output of each sensor is used as an input to ARX model to estimate the response of the reference channel of that cluster. Using both data types, the ARX based time series analysis method is shown to be effective for damage detection and localization along with the interpretations and conclusions.

• Smart Structures and Systems
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• v.20 no.2
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• pp.163-173
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• 2017

Structural health monitoring (SHM) of civil infrastructure using fiber Bragg grating sensor networks (FBGSNs) has received significant public attention in recent years. However, there is currently little research on the health-monitoring technology of high-piled wharfs in coastal ports using the fiber Bragg grating (FBG) sensor technique. The benefits of FBG sensors are their small size, light weight, lack of conductivity, resistance corrosion, multiplexing ability and immunity to electromagnetic interference. Based on the properties of high-piled wharfs in coastal ports and servicing seawater environment and the benefits of FBG sensors, the SHM system for a high-piled wharf in the Tianjin Port of China is devised and deployed partly using the FBG sensor technique. In addition, the health-monitoring parameters are proposed. The system can monitor the structural mechanical properties and durability, which provides a state-of-the-art mean to monitor the health conditions of the wharf and display the monitored data with the BIM technique. In total, 289 FBG stain sensors, 87 FBG temperature sensors, 20 FBG obliquity sensors, 16 FBG pressure sensors, 8 FBG acceleration sensors and 4 anode ladders are installed in the components of the back platform and front platform. After the installation of some components in the wharf construction site, the good signal that each sensor measures demonstrates the suitability of the sensor setup methods, and it is proper for the full-scale, continuous, autonomous SHM deployment for the high-piled wharf in the costal port. The South 27# Wharf SHM system constitutes the largest deployment of FBG sensors for wharf structures in costal ports to date. This deployment demonstrates the strong potential of FBGSNs to monitor the health of large-scale coastal wharf structures. This study can provide a reference to the long-term health-monitoring system deployment for high-piled wharf structures in coastal ports.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.544-547
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• 2008

In 1990, Korea building contractors were indifferent maintenance management cause focus on completion of construction before construction collapsed. Currently, structures monitoring systems are restrictive on large structures. Structures monitoring systems are limited many old and small structures in the whole nation. Recently, we make efforts application Ubiquitous technology as like sensor, sensor network system, and wireless communication system in construction. This paper applies bridge management system using Ubiquitous skill which is real-time monitoring report offering system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.654-670
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• 2020

Workers at construction sites are easily exposed to many dangers and accidents involving falls, tripping, and missteps on stairs. However, researches on construction site monitoring system to prevent work-related injuries are still insufficient. The purpose of this study was to develop a wearable textile pressure insole sensor and examine its effectiveness in managing the real-time safety of construction workers. The sensor was designed based on the principles of parallel capacitance measurement using conductive textile and the monitoring system was developed by C# language. Three separate experiments were carried out for performance evaluation of the proposed sensor: (1) varying the distance between two capacitance plates to examine changes in capacitance charges, (2) repeatedly applying 1 N of pressure for 5,000 times to evaluate consistency, and (3) gradually increasing force by 1 N (from 1 N to 46 N) to test the linearity of the sensor value. Five subjects participated in our pilot test, which examined whether ascending and descending the stairs can be distinguished by our sensor and by weka assessment tool using k-NN algorithm. The 10-fold cross-validation method was used for analysis and the results of accuracy in identifying stair ascending and descending were 87.2% and 90.9%, respectively. By applying our sensor, the type of activity, weight-shifting patterns for balance control, and plantar pressure distribution for postural changes of the construction workers can be detected. The results of this study can be the basis for future sensor-based monitoring device development studies and fall prediction researches for construction workers.

• International Journal of High-Rise Buildings
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• v.4 no.1
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• pp.27-37
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• 2015

Structural health monitoring is becoming more and more important in the domain of civil engineering as a proper mean to increase and maintain the safety, especially in the land of earthquakes like Japan. In many civil structures, the deformations are the most relevant parameter to be monitored. In this context, a monitoring technology based on the use of long-gage fiber optic deformation sensor, SOFO is being applied to a 33-floors tall building in Tokyo. Sensors were installed on the $2^{nd}$ floor's steel columns of the building on May 2005 in the early stage of the construction. The installed SOFO sensors were dynamic compatible ones which enable both static and dynamic measurements. The monitoring is to be performed during the whole lifespan of the building. During the construction, static deformations of the columns had been measured on a regular basis using a reading unit for static measurement and dynamic deformation measurements were occasionally conducted using a reading unit for dynamic measurement. The building was completed on August 2006. After the completion, static and dynamic deformation measurements have been continuing. This paper describes a health monitoring technology, SOFO system which is applicable to high-rise buildings and monitoring results of a 33-floors tall building in Tokyo from May 2005 to October 2010.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1324-1327
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• 2009

Social infrastructure is the basis of public welfare and should be recognized and managed as important assets. Bridge is one of the most important infrastructures to be managed systematically because the impact of the failure is critical. It is essential to monitor the performance of bridges in order to manage them as an asset. But current analytical methods such as predictive modeling and structural analysis are very complicated and difficult to use in practice. To apply these methods, structural and material condition data collection should be performed in each element of bridge. But it is difficult to collect these detailed data in large numbers and various kinds of bridges. Therefore, it is necessary to collect data of major measurement items and predict the life of bridges roughly with advanced information technologies. When certain measurement items reach predefined limits in the monitoring bridges, precise performance measurement will be done by detailed site measurement. This paper describes the selection of major measurement items that can represent the tendency of bridge life and introduces automated bridge data collection test-bed using wireless sensor network technology. The following will be major parts of this paper: 1) Examining the features of conventional bridge management system and data collection method 2) Mileage concept as a bridge life indicator and measuring method of the indicator 3) Test-bed of automated and real-time based bridge life indicator monitoring system using wireless sensor network