• KIEAE Journal
• /
• v.7 no.4
• /
• pp.147-152
• /
• 2007

Numerous non-destructive tests(NDT) to assess the safety of real structures have been developed. System identification(SI) techniques using dynamic responses and behaviors of structural systems become an outstanding issue of researchers. However the conventional SI techniques are identified to be non-practical to the complex and tall buildings, due to limitation of the availability of an accurate data that is magnitude or location of external loads. In most SI approaches, the information on input loading and output responses must be known. In many cases, measuring the input information may take most of the resources, and it is very difficult to accurately measure the input information during actual vibrations of practical importance, e.g., earthquakes, winds, micro seismic tremors, and mechanical vibration. However, the desirability and application potential of SI to real structures could be highly improved if an algorithm is available that can estimate structural parameters based on the response data alone without the input information. Thus a technique to estimate structural properties of building without input measurement data and using limited response is essential in structural health monitoring. In this study, shaking table tests on three-story plane frame steel structures were performed. Out-put only model analysis on the measured data was performed, and the dynamic properties were inverse analyzed using least square method in time domain. In results damage detection was performed in each member level, which was performed at story level in conventional SI techniques of frequency domain.

• Journal of architectural history
• /
• v.17 no.3
• /
• pp.61-80
• /
• 2008

The purpose of this study is to discover the characteristics and the change of the framed structure with triple beam. 61 existing buildings with the triple beam structure were selected and analyzed extensively. The result of this study could be described in detail like below. The triple beam structure is used in the highly graded and symbolized building like the Buddhist sanctum and the Confucian sanctum. And the triple beam structure was chiefly used in $1600{\sim}1800's$. Generally, 1 Koju-type with Toikan(退間) is applied to the triple beam structure. Despite of the sameness of framed structure, there is a tendency that the rear Toikan(後退間) is used in the Buddhist sanctum and the front Toikan(前退間) is used in the Confucian sanctum. This different application of the Toikan(退間) resulted from the different spatial characteristics which reflect function and grade of the building. The application of Sangjungdori(上中道里, upper purlin) and two Danyeon(短椽, short rafter) is a necessary consequence, because Jungbo(중보, middle beam) is located between Daebo(대보, beam) and Jongbo(종보, small and high located beam) as an additional member of frame. And these are essential characteristics of the framed structure with triple beam. The triple beam structure is formed in a transitional period, as the result from eliminating the inner high-column from the 2 Koju and double beam structure. Though the Daebo is longer, the structure is more stable. But the rate of application of the triple beam structure is low, because it does not exceed the double beam structure in merits. Some of buildings with the triple beam structure has the asymmetrical characteristic in design, which is appeared in the latter period of Joseon Dynasty.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.8
• /
• pp.1605-1614
• /
• 2009

The technique of simultaneous localization and mapping is the most important research topic in mobile robotics. In the process of building a map in its available memory, the robot memorizes environmental information on the plane of grid or topology. Several approaches about this technique have been presented so far, but most of them use mapping technique as either grid-based map or topology-based map. In this paper we propose a frame of solving the SLAM problem of linking map covering, map building, localizing, path finding and obstacle avoiding in an automatic way. Some algorithms integrating grid and topology map are considered and this make the SLAM performance faster and more stable. The proposed scheme uses an occupancy grid map in representing the environment and then formulate topological information in path finding by A${\ast}$ algorithm. The mapping process is shown and the shortest path is decided on grid based map. Then topological information such as direction, distance is calculated on simulator program then transmitted to robot hardware devices. The localization process and the dynamic obstacle avoidance can be accomplished by topological information on grid map. While mapping and moving, pose of the robot is adjusted for correct localization by implementing additional pixel based image layer and tracking some features. A laser range finer and electronic compass systems are implemented on the mobile robot and DC geared motor wheels are individually controlled by the adaptive PD control method. Simulations and experimental results show its performance and efficiency of the proposed scheme are increased.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.12 no.4
• /
• pp.35-44
• /
• 2008

A self-centering energy-dissipative(SCED) bracing system has recently been developed as a new seismic force resistant bracing system. The advantage of the SCED brace system is that, unlike other comparable advanced bracing systems that dissipate energy such as the buckling restrained brace(BRB) system, it has a self-centering capability that reduces or eliminates residual building deformations after major seismic events. In order to investigate the effects of torsion on the SCED brace and BRB systems, nonlinear time history analyses were used to compare the responses of 3D model structures with three different amounts of frame eccentricity. The results of the analysis showed that the interstory drifts of SCED braced frames are more uniform than those of BRB frames, without regard to irregularity. The residual drift and residual rotation responses tended to decrease as irregularity increased. For medium-rise structures, the drift concentration factors(DCFs) for SCED systems were lower than those for BRB frames. This means that SCED-braced frames deform in a more uniform manner with respect to building height. The effect of the torsional irregularity on the magnitude of the DCFs was small.

• Smart Structures and Systems
• /
• v.20 no.2
• /
• pp.127-137
• /
• 2017

Identification of damping characteristics is of significant importance for dynamic response analysis and condition assessment of structural systems. Damping is associated with the behavior of the energy dissipation mechanism. Identification of damping ratios based on the sensitivity of dynamic responses and the model updating technique is investigated with numerical and experimental investigations. The effectiveness and performance of using the sensitivity-based model updating method and vibration monitoring data for damping ratios identification are investigated. Numerical studies on a three-dimensional truss bridge model are conducted to verify the effectiveness of the proposed approach. Measurement noise effect and the initial finite element modelling errors are considered. The results demonstrate that the damping ratio identification with the proposed approach is not sensitive to the noise effect but could be affected significantly by the modelling errors. Experimental studies on a steel planar frame structure are conducted. The robustness and performance of the proposed damping identification approach are investigated with real measured vibration data. The results demonstrate that the proposed approach has a decent and reliable performance to identify the damping ratios.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.1
• /
• pp.39-46
• /
• 2017

In this paper, a model updating procedure based on the response surface method combined with the multi-objective optimization was proposed and applied for updating of the FE models representing a low-rise reinforced concrete building before and after the seismic retrofit. The dynamic properties to be matched were obtained from vibration tests using a small shaker system. By varying the structural parameters according to the central composite design, analysis results from the initial FE model using a commercial software were collected and used to produce two regression functions each of which representing the errors in the natural frequencies and mode shapes. The two functions were used as the objective functions for multi-objective optimization. Final solution was determined by examining the Pareto solutions with one iteration. The parameters representing the stiffnesses of existing concrete, masonry, connection stiffness in expansion joint, new concrete, retrofitted members with steel section jacketing were selected and identified.

• Fire Science and Engineering
• /
• v.4 no.2
• /
• pp.3-13
• /
• 1990

Fire Protection System is facilities that Control the fire by mechanic means. Buildings Over a Certain Scale is required this system. As the small from the fire extinguisher as the large to the sprinkler system of automatic fire extinguishing equipment the kinds are various. With the development of architecture technique while modern higher buildings are increased. As fire is a first product that human make, it performed many profits and services for our mankind. Sometimes as it is profitable fire or harmful fire, it takes charge of human's life culture. Therefore fire protection system is facilities that control the ]after fire by mechanic means Building over a certain scale is required this system. As the small from the fire extinguisher as the large to the sprinkler system of automatic fire extinguishing equipment, the kinds are various. With the development of architecture technique while modern Higher buildings are increased high level and fire prevent facilities aren't reached to that level. The object of this study is present the problem which appear from the analysis of place standard for fire protection facility. This study described as a following order. First. We are going to look history of the fire protection system and change course of that with the year and facility. Second, We say the frame system and special nature of the foreign fire prevent Act. Third. We understand the control reality of fire protection system. Fourth. We took out the merit of foreign fire prevent law and the problem of our current domestic system. The placing standard of proper fire protection facilities that be presented from this study are followed next. 1) We have reinforce sprinkler system placing standard for the fire extinguishing and check the spread of fire. 2) We must to be ruled the standard for keeping fire prevention system that are received reality and people's idea. 3) We should prepare lawful basis which can be place fire prevention center. 4) We have to correct the standard of use about complex building without mainuse and we take increase the real effectiveness of this. 5) We ought to match the use of current fire prevention act and the use of architecture law.

• Journal of architectural history
• /
• v.21 no.3
• /
• pp.73-92
• /
• 2012

This study mainly inquired characteristics and changes of 'Chang-aelgool' through 38 cases(with 161 Ssang-chang) of annex and pavillion buildings in Yeong-nam region which are built during the Chosun dynasty. The method of inquiry included actual survey of windows along with bibliographical research, and the results are as below. First, through the discovery of the term 'Chang-aelgool' as an indication of the window-forming frame in 'YeongGeonUiGwe'(1680 A.D), it is apparent that the term 'Chang-aelgool' was widely used in Korea from the late 17th century. Second, the 'Chang-aelgool' of study objects are classified into 4 categories. Type I and II are comprised of mitre-joints which cover the 4 corners of 'Chang-aelgool' and mainly used in building annex and pavillion buildings during the early period of the Chosun dynasty. Type III was widely used during the early and middle period of the Chosun dynasty and drastically dropped in number during the late period of the dynasty. Type IV is comprised of mitre-joint of the upper-half, tenon-jointing of the lower-half and widely used in annex and pavillion building during the late period of the Chosun dynasty. Third, the form of 'Chang-aelgool' has changed from rectangular form with longer width during the early period of Chosun dynasty to square form during the middle period and eventually ended up as a rectangular form with longer height during the late period of the dynasty. Fourth, it is considered that while mullion which is located in the center of 'Chang-aelgool' was mainly used around the main floored room during the early period of the Chosun dynasty, became commonly used in main floored room and 'ondol' rooms during the middle period and drastically dropped in number from then and ended up being not in use after the mid 18th century.

• Journal of architectural history
• /
• v.26 no.4
• /
• pp.19-34
• /
• 2017

The purpose of this study was to comprehend the assignment and the procurement method of wood works' craftsman through the Salleung-dogamuigwes in royal tombs constructions in the late Joseon period. Following conclusions have been reached through the study. First, Carpenter and other nine craftsmen were introduced in carpentry works. The craftsmen were put in by occupation to maintain the quality of the government building construction by wood processing area. It was distinguished by frame member, Sujangjae, window framing wood, decorative member. Second, sawyer showed a sharp increase in the latter half of the 18th century and declined since the middle of the 19th century. This is closely related to the increase in demand for building materials and the growth of civilian wood products. As a maximum of 300 people have been assigned to the craftsmen in the woodwork, it can be seen that the work has been divided by the process. Third, the national carpenter was difficult to procure from the 17th century to the beginning of the 18th century. From the middle 18th century, the system procuring national carpenter was stabilized. In the 19th century, the input ratio of the national craftsmen seems to have decreased significantly and seems to have kept it at the minimum level. Forth, sawyer were procured through Seongonggam from the late 18th century through the mid 19th century. That means that the role of the sawyer had become important. Since Jogakjang is not a necessary manpower, it usually has civilian artisans.

• Earthquakes and Structures
• /
• v.13 no.3
• /
• pp.267-277
• /
• 2017

Base-isolation is now being adopted as a retrofitting strategy to improve seismic behaviour of reinforced concrete (r.c.) framed structures subjected to far-fault earthquakes. However, the increase in deformability of a base-isolated framed building may lead to amplification in the structural response under the long-duration horizontal pulses of high-magnitude near-fault earthquakes, which can become critical once the strength level of a fire-weakened r.c. superstructure is reduced. The aim of the present work is to investigate the nonlinear seismic response of fire-damaged r.c. framed structures retrofitted by base-isolation. For this purpose, a five-storey r.c. framed building primarily designed (as fixed-base) in compliance with a former Italian seismic code for a medium-risk zone, is to be retrofitted by the insertion of elastomeric bearings to meet the requirements of the current Italian code in a high-risk seismic zone. The nonlinear seismic response of the original (fixed-base) and retrofitted (base-isolated) test structures in a no fire situation are compared with those in the event of fire in the superstructure, where parametric temperature-time curves are defined at the first level, the first two and the upper levels. A lumped plasticity model describes the inelastic behaviour of the fire-damaged r.c. frame members, while a nonlinear force-displacement law is adopted for the elastomeric bearings. The average root-mean-square deviation of the observed spectrum from the target design spectrum together with a suitable intensity measure are chosen to select and scale near- and far-fault earthquakes on the basis of the design hypotheses adopted.