Papers by Author: Ki Tae Park

Abstract: Structural health monitoring (SHM) has been applied to huge and important civil structures. Its role is for obtaining readings of sensors, analysis for data, and estimation of structural behavior and service life. Essential element is to obtain the accurate and many measurements of sensors attached to structural members for estimating reliable structural behavior and avoiding sudden collapse. Although technologies for new type of sensor and data process have been grown, there are still members those are not monitored or exactly estimated. The representative examples are the present prestress force in strand and fastening state of bolt connection. Despite the fact that failure of prestressed strand and bolt may lead a catastrophe by sudden failure, monitoring for them has not been performed fully due to the lack of practical, economic, and quantified ways. In this paper, two sensing systems were introduced. One is anchor head load cell able to measure present prestress force and another is detecting system for the loosening of bolt connection. With these sensing systems, connected members with prestressed tendon or bolt connection can be maintained successfully.

Abstract: The first long-term bridge monitoring system in Korea was installed in 1995, and many bridges have been maintained by long-term monitoring systems. Recently, reliability of data and cost effectiveness have been increased by advanced sensor technology (fiber optic sensor, RFID, USN etc) and measuring equipment. In Korea, the large-scale project for the safety network integration for long-term smart monitoring systems for bridge structures started in 2007, and this is the second year of the project. In this system, various innovative sensor types are considered. To increase the effectiveness of this network system, an analysis of the problems with the conventional long-term bridge monitoring system and solution investigations are needed. The biggest problems are low durability and data reliability because of noise, and the lack of data applications techniques. Therefore, in this paper, a brief summary of the projects is presented and the state of bridge monitoring systems in Korea is investigated, and various problems and solutions for these problems are briefly suggested.

Abstract: In general, structures in service gradually lose their original performance-level over time due to initial defects in design and construction, or exposure to unfavorable external conditions such as repeated loading or deteriorating environment, and in extreme cases, may collapse. So, in order to maintain the serviceability of structures at optimal level, advanced structure measuring system which can inform optimal time point and method of maintenance is required in addition to accurate prediction of residual life of the structure by periodic inspection. In Korea, the large-scale project for the safety network integration for long-term smart monitoring systems for bridge structures started in 2007, and this is the second year of the project. In this system, various structure types such as bridge, tunnels and cut slopes were considered with an emphasis on safety. The purpose of this system is to integrate the operation centers for these structure types in order to control and evaluate the structure’s real-time safety level through measured behavioral data. In this paper, the progress methodology for this network system and the smart monitoring system installation techniques for each structure types are briefly suggested.