• Journal of the Korean Institute of Educational Facilities
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• v.28 no.6
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• pp.3-12
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• 2021

• Structural Engineering and Mechanics
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• v.82 no.5
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• pp.557-569
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• 2022

The retrofit of existing structures in high seismic zones is a crucial issue in the earthquake engineering field. The interest of the research community is particularly high for the structures that do not respect current seismic codes and present structural deficiencies such as poor detailing and lack of capacity design provisions. A reinforced concrete (RC) school building is used as case study to show the influence of different knowledge levels on the seismic retrofitting cost assessment. The safety assessment of the case study building highlights deficiencies under both vertical and seismic loads. By considering all the possible knowledge levels defined by the Italian such as by the European codes in order to derive the mechanical properties of the school building constitutive materials, the retrofit operations are designed to achieve different seismic safety thresholds. The retrofit structural costs are calculated and summed up to the costs for in-situ in tests. The paper shows how for the case study building the major costs spent for a large number of in-situ tests allows to save a consistent amount of money for retrofit operations. The hypothesis of demolition and reconstruction of the building is also compared in terms of costs with all the analyzed retrofit options.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.647-652
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• 2011

Developments in the teaching of the National Diploma in Building students should be geared towards meeting the needs of the construction industry in South Africa. These needs are usually in the form of skills and knowledge required to resolve thorny issues encountered in practice. The lack of capacity in the construction industry needs to be addressed from the basis of ensuring that the education system caters for both mature entry and matriculation entry students. The paper looks at a comparison in performance between mature entry and matriculation (just finish High School) entry students focusing on the National Diploma in Building students at the University of Johannesburg. The paper will make a comparison between those students who work first before enrolling for their first year National Diploma in Building and those who are directly from high school. Cooperative education involves training and systematically developing students through the acquisition of the requisite skills, attitudes, values and knowledge required to adequately perform in their chosen careers. The paper describes the problems and experiences that have been encountered by both mature and matriculation entry students in their three years of study which affects their performance. The paper will then look at the value of prior experience in enabling students to finish their National Diploma in Building within a three year period. The paper closes with some recommendations for the future.

• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.116-126
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• 2011

Recently, eco-friendly energy has been employed in diverse fields of industry in order to reduce environmental pollution and secure a new growth engine. In particular, practical applications of photovoltaic energy, such as building integrated photovoltaic systems, have been implemented to the construction industry based on the extensive interest in photovoltaic power as an unlimited and sustainable energy. While the construction of a high-rise building requires large amounts of energy, methods of reducing energy consumption in the construction phase have rarely been studied. Based on this motivation, the research proposes a photovoltaic based formwork system (PVFS), and then performs a design and feasibility analysis for its application to the construction of a high-rise building. Using a case study, the research implements various analyses, including area, position, and total allowable weight required by PVFS, and evaluates the influences of PVFS on the construction processes, as well as its economic feasibility. The proposed PVFS can be adopted to a real-world project in the near future, depending on the advancement of technology and economic feasibility. The results of this research will contribute to establishing a construction environment that promotes a reduction of energy consumption by using eco-friendly energy in the construction phase.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.6
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• pp.391-400
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• 2016

For earthquake loss estimation of building structures in Gangnam-Gu district in Seoul, three scenario earthquakes were selected by comparison of the response spectra of these scenario earthquakes with the design spectrum in Korean Building Code (KBC 2009), and then direct losses of the building structures in the Gangnam-Gu district under each scenario earthquake are estimated. The following conclusions are drawn from the results of damage and loss in the second scenario earthquake, which has a magnitude = 6.5 and epicentral distance =15 km: (1) The ratio of building stocks undergoing the extensive and complete damage level is 40.0% of the total. (2) The amount of direct economic losses appears approximately 19 trillion won, which is 1.2% of the national GDP of Korea. (3) About 25% of high-rise (over 10-story) RC building wall structures, were inflicted with the damage exceeding moderate level, when compared to 60% of low-rise building structures. (4) From the economical view point, the main loss, approximately 50%, was caused by the damage in the high-rise RC wall building structures.

• Structural Engineering and Mechanics
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• v.78 no.3
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• pp.305-317
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• 2021

An AMD control system is usually built based on the original model of a target building. As a result, the fact leads a large calculation workload exists. Therefore, the orders of a structural model should be reduced appropriately. Among various model-reduction methods, a suitable reduced-order model is important to high-rise buildings. Meanwhile, a partial structural information is discarded directly in the model-reduction process, which leads to the accuracy reduction of its controller design. In this paper, an optimal technique is selected through comparing several common model-reduction methods. Then, considering the dynamic characteristics of a high-rise building, an improved balanced truncation (BT) method is proposed for establishing its reduced-order model. The abandoned structural information, including natural frequencies, damping ratios and modal information of the original model, is reconsidered. Based on the improved reduced-order model, a new reduced-order controller is designed by a regional pole-placement method. A high-rise building with an AMD system is regarded as an example, in which the energy distribution, the control effects and the control parameters are used as the indexes to analyze the performance of the improved reduced-order controller. To verify its effectiveness, the proposed methodology is also applied to a four-storey experimental frame. The results demonstrate that the new controller has a stable control performance and a relatively short calculation time, which provides good potential for structural vibration control of high-rise buildings.

• Wind and Structures
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• v.6 no.5
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• pp.403-418
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• 2003

This paper presents an extensive analysis of the short term, unsteady wind loading on a low-rise building. The building is located in a rural environment and only the specific situation of wind flow orthogonal to the long face of the structure is considered. The data is analysed using conventional analysis and less traditional methods such as conditional sampling and wavelet analysis. The nature of the flow field over the building is found to be highly unsteady and complex. Fluctuating pressures on the windward wall are shown to a large extent to be caused by the fluctuations in the upstream flow, whereas extreme pressures on the roof are as a result of high intensity small scale flow structures. On the roof of the building a significant amount of energy is shown to exist at frequencies above 1 Hz.

• International Journal of High-Rise Buildings
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• v.10 no.1
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• pp.35-43
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• 2021

With the rapid urbanization and growing energy use intensity in the built environment, the glazed curtainwall has become ever more important in the architectural practice and environmental stewardship. Besides its energy efficiency roles, window has been an important transparent component for daylight penetration and a view-out for occupant satisfaction. In response to the climate crisis caused by the built environment, this research focuses on the study of net-zero energy retrofitting by using a new building integrated photovoltaic (BIPV) curtainwall as a sustainable alternative to conventional window systems. Design variables such as building orientations, climate zones, energy attributes of BIPV curtainwalls, and glazed area were studied, to minimize energy consumption and discomfort hours for three cities representing hot (Miami, FL), mixed (Charlotte, NC), and cold (Minneapolis, MN). Parametric analysis and Pareto solutions are presented to provide a comprehensive explanation of the correlation between design variables and performance objectives for net-zero energy retrofitting applications.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.893-903
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• 2022

Recently, computer vision (CV)-based safety monitoring (i.e., object detection) system has been widely researched in the construction industry. Sufficient and high-quality data collection is required to detect objects accurately. Such data collection is significant for detecting small objects or images from different camera angles. Although several previous studies proposed novel data augmentation and synthetic data generation approaches, it is still not thoroughly addressed (i.e., limited accuracy) in the dynamic construction work environment. In this study, we proposed a game engine-driven synthetic data generation model to enhance the accuracy of the CV-based object detection model, mainly targeting small objects. In the virtual 3D environment, we generated synthetic data to complement training images by altering the virtual camera angles. The main contribution of this paper is to confirm whether synthetic data generated in the game engine can improve the accuracy of the CV-based object detection model.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.516-516
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• 2002

With the wide usage of LiDAR data and high-resolution satellite image, 3D modeling of buildings in urban areas has become an important research topic in the photogrammetry and computer vision field for many years. However the previous modeling has its limitations of merely texturing the image to the DSM surface of the study area and does not represent the relief of building surfaces. This study is focused on presenting a system of realistic 3D building modeling from consecutive stereo image sequences using digital camera. Generally when acquiring images through camera, various parameters such as zooming, focus, and attitude are necessary to extract accurate results, which in certain cases, some parameters have to be rectified. It is, however, not always possible or practical to precisely estimate or rectify the information of camera positions or attitudes. In this research, we constructed the collinearity condition of stereo images through extracting the distinctive points from stereo image sequence. In addition, we executed image matching with Graph Cut method, which has a very high accuracy. This system successfully performed the realistic modeling of building with a good visual quality. From the study, we concluded that 3D building modeling of city area could be acquired more realistically.