• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.401-402
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• 2023

The shear connection of the vertical construction joint of a slurry wall by the concrete shear key has excellent structural performance and is economical and eco-friendly. However, technology for forming concrete shear keys in the underground is still underdeveloped. This paper proposes the development of the construction technology required to form a concrete shear key at the vertical construction joint of the slurry wall.

• Advances in concrete construction
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• v.5 no.5
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• pp.469-479
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• 2017

Balanced cantilever construction is extensively used in the construction of prestressed concrete (PSC) box-girder bridges. Shear-lag effect is usually considered in finished bridges, while the cumulative shear-lag effect in bridges during balanced cantilever construction is considered only rarely. In this paper, based on the balanced cantilever construction sequences of large-span PSC box-girder bridges, the difference method is employed to analyze the cumulative shear-lag effect of box girders with varying depth under the concrete segments' own weight. During cantilever construction, no negative shear-lag effect is generated, and the cumulative shear-lag effect under the balanced construction procedure is greater than the instantaneous shear-lag effect in which the full dead weight is applied to the entire cantilever. Three cross-sections of Jianjiang Bridge were chosen for the experimental observation of shear-lag effect, and the experimental results are in keeping with the theoretical results of cumulative shear-lag effect. The research indicates that only calculating the instantaneous shear-lag effect is not sufficiently safe for practical engineering purposes.

• International Journal of High-Rise Buildings
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• v.8 no.3
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• pp.185-192
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• 2019

Citic Tower is the first over-500 m-tall super highrise building in the world, located in the high seismic intensity area with paek ground acceleration over 0.2g in 475 years. This project is unique in its complexity, large volume, and challenging site conditions (zero site for construction). The traditional techniques can hardly meet safty, quality and schedule requirements of the construction. This article introduces the key construction technologies that are innovatively developed and applied in Citic Tower project construction, including intelligent super-high-rise building integrated construction platform system, independently developed by the CCTEB; Jump-Lift Elevator, which is the first of the kind with service height over 500 meters; combined temporary-and-permanent fire protection systems. The BIM technology is also applied in this project. Through technical innovation, and utilization of technologies, construction speed and safety had been greatly improved.

• Smart Structures and Systems
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• v.32 no.4
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• pp.267-279
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• 2023

Data modelling and interpretation for structural health monitoring (SHM) field data are critical for evaluating structural performance and quantifying the vulnerability of infrastructure systems. In order to improve the data modelling accuracy, and extend the application range from data regression analysis to out-of-sample forecasting analysis, an improved most likely heteroscedastic Gaussian process (iMLHGP) methodology is proposed in this study by the incorporation of the outof-sample forecasting algorithm. The proposed iMLHGP method overcomes this limitation of constant variance of Gaussian process (GP), and can be used for estimating non-stationary typhoon-induced response statistics with high volatility. The first attempt at performing data regression and forecasting analysis on structural responses using the proposed iMLHGP method has been presented by applying it to real-world filed SHM data from an instrumented cable-stay bridge during typhoon events. Uncertainty quantification and correlation analysis were also carried out to investigate the influence of typhoons on bridge strain data. Results show that the iMLHGP method has high accuracy in both regression and out-of-sample forecasting. The iMLHGP framework takes both data heteroscedasticity and accurate analytical processing of noise variance (replace with a point estimation on the most likely value) into account to avoid the intensive computational effort. According to uncertainty quantification and correlation analysis results, the uncertainties of strain measurements are affected by both traffic and wind speed. The overall change of bridge strain is affected by temperature, and the local fluctuation is greatly affected by wind speed in typhoon conditions.

• Structural Engineering and Mechanics
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• v.76 no.2
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• pp.269-278
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• 2020

In this paper, the mechanical characteristics of the open type hyperbolic-parabolic membrane structure under wind load were investigated. First, the numerical simulation of a typical plane membrane structure was performed based on the Large-Eddy Simulation method. The accuracy of the simulation method was validated by the corresponding wind tunnel test results. Then, the wind load shape coefficients of open type hyperbolic-parabolic membrane structures are obtained from the series of numerical calculations and compared with the recommended values in the "Technical Specification for Membrane Structures (CECS 158: 2015). Finally, the influences of the wind directions and wind speeds on the mean wind pressure distribution of open type hyperbolic-parabolic membrane structures were investigated. This study aims to gain a better understanding of the wind-induced response for this type of structure and be useful to engineers and researchers.

• Architectural research
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• v.25 no.1
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• pp.11-17
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• 2023

This study aims to derive key construction supervision work that can be digitalized among construction supervision work. The scope of the study includes domestic construction sites to which the Building Act of South Korea is applied. First, the construction supervision process was identified through extensive consultation of construction expert witnesses. Afterwards, the key construction supervision works for digitization were derived through survey results construction expert witnesses. Among the 24 supervision works throughout the pre-construction, construction, and post-construction stages, the proportion of supervision work manpower or cost, the type of data generated by supervision work and the urgency of introducing digital technology, and the impact on productivity and safety of supervision work were evaluated on a 5-point scale from "very low" to "very high" was investigated. The survey was conducted by t-test analysis, and as a result, it was possible to derive that the level of digitization was higher than average in "quality management," "safety management," and "collection and cooperation of maintenance instructions." It can be interpreted that digitization has been introduced on a pilot testing basis or has already been completed according to the needs of the site. On the other hand, it can be interpreted that the work that are obtained below the average score are considered to be realistically constrained at the construction site and that it is inevitable for the supervisor to proceed manually. Future studies include analyzing the quantitative impact of the key construction supervision work once digitalization is fully applied.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.624-635
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• 2012

Construction projects, including housing, are carried out over long periods of time. According to changes to the construction period, the cost of input materials and wages also changes. Therefore appropriate management is important in order to minimize cost risks caused by fluctuations in prices. In Korea, housing units are usually sold in lots prior to construction completion. Therefore, careful management of input elements such as materials and equipment that are sensitive to price fluctuations is very important. This study deals with how the price fluctuation of materials, labor, and equipment influences the change of housing cost and seeks a way for cost management through identifying key resources sensitive to price fluctuation. As a result, a change to the housing cost index multiplies depending on cost changes of materials and labor together. Labor costs are a major factor on the housing cost index. In addition, certain types of materials and labor input to housing construction greatly influence price fluctuations. Thus, it is found that managing those main cost factors is the key for effective cost management.

• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.235-244
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• 2011

Failures of segmental bridges have been attributed to the inadequate joint connection techniques, which led to corrosion of the post-tensioned tendons connecting the segmental joints. The principal objective of this study is to evaluate the performances of the in-situ cast joint and epoxy applied shear key joints as a function of shear and ultimate strengths. Furthermore, shear behavior and strength of shear key joints in ultra high performance precasted concrete segmental bridges are experimentally evaluated to understand its shear failure behavior. The test parameters of shear key shape and type, load-displacement relations, cracking behavior, concrete strength, and fracture modes are considered in the study. Also, several parameters which influence the mechanical behavior of the shear key joint are analyzed. Based on the study results, the optimal shear key shape and joint type are proposed for the joint design and analysis guidelines.

• Journal of the Korean Geotechnical Society
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• v.31 no.3
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• pp.17-25
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• 2015

In this study, a new segment assembling method using cable tensible force and island-type shear key was developed to improve the problems of bolt assembling method of shield tunnel. The bolting system and island-type shear key system were compared to analyze the mechanical behavior that occurs in the segment. The study results obtained from structural investigation and numerical analysis technique showed that the shear strength of island-type shear key is higher than that of the bolt system. With the increase of the tensile strength, it is expected that the stability of the segment will be secured.

• Steel and Composite Structures
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• v.24 no.1
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• pp.37-52
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• 2017

To quantitatively assess the safety against seismic collapse of eccentrically braced steel frame (EBSF) system, 24 typical EBSFs with K-shape and V-shape braces with seismic precautionary intensities 8 and 9 were designed complying with China seismic design code and relative codes to constitute archetype space of this structure system. In the archetype space, the collapse probability of the structural system under maximum considered earthquakes (MCE) was researched. The results show that the structures possess necessary safety against seismic collapse when they respectively encounter the maximum considered earthquakes corresponding to their seismic precautionary levels, and their collapse probabilities increase with increasing seismic precautionary intensities. Moreover, the EBSFs with V-shape braces have smaller collapse probability, thus greater capacity against seismic collapse than those with K-shape braces.