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In determining wind loads when designing buildings—especially high-rise buildings—wind speed is a critical factor. With increased progression of city high-rise construction, accurate prediction has become ever more important. Many factors, such as local climates, roughness of surrounding conditions, and terrain, may affect wind speed. But among all factors considered, terrain has a very large influence. Difficulties in reflecting the influence of terrain on wind speed include (1) collecting topographic data information; (2) quantitatively evaluating terrain features; and (3) expressing specific area relationships with surrounding observation stations. This paper poses means to solve these limitations by (1) using satellite imagery to gather topographic information; (2) evaluating terrain quantitatively with convolutional neural network (CNN)–based encoders; and (3) employing a graph neural network (GNN) to estimate the wind speed relationship of an arbitrary place to that of observation stations. Herein, a machine learning model utilizing the aforementioned means was proposed. To support this model, an experiment was conducted using observed wind speed data in Korea. Throughout the experiment, previous studies were used to compare results with ratification of the posed model. Given the submitted findings, further research and investigation to establish correlation with other experimental case results are proposed. [ABSTRACT FROM AUTHOR]

The artificial ground freezing (AGF) method is an environmentally friendly ground improvement technique for numerous geotechnical applications. It can be used in fine-grained soils, which may not be efficiently improved via conventional cement-based ground improvement techniques. However, some of the issues hindering the application of the AGF method to fine-grained soils include inefficiency in achieving the target volume of frozen soil and degradation in mechanical properties of the soil after the freezing-thawing process. In this paper, the freezing rate and degradation in strength and stiffness of a clayey silt in South Korea were investigated using field experiments. At two different outlet temperatures (−180°C and −120°C), liquid nitrogen was injected into the freezing pipe to evaluate the freezing rate. A simple equation to estimate the theoretical radial freezing rate was proposed and compared with the experimental results. In addition, a piezocone penetration test (CPTu) and pressuremeter test (PMT) were performed to assess the degradation in strength and stiffness of the soil after the freezing-thawing process. Results of the CPTu, PMT, and laboratory experiments revealed that the degradation in mechanical properties of Korean clayey silt could be attributed to the rearrangement of soil particles. [ABSTRACT FROM AUTHOR]

Construction projects are known for their dynamic and everchanging nature, characterized by frequent adjustments and temporary durations. Consequently, workers must be aware of evolving hazards and promptly share safety-related knowledge and information with colleagues. Despite extensive prior research conducted on knowledge-sharing behavior within the construction industry, there is a lack of studies focusing on the factors that affect the safety knowledge-sharing behaviors (SKSB) of construction field workers (CFWs) who work in the most hazardous frontline positions at construction sites. Therefore, this study aims to identify the major factors influencing SKSB among CFWs and examine their relationships. To achieve this, the study adopts the theory of reasoned action as the theoretical framework supplemented by a comprehensive literature review that identifies four influential factors. A questionnaire survey involving 252 CFWs from 16 construction sites in South Korea was conducted, and the responses of 146 participants were analyzed using social network analysis and structural equation modeling. By advancing research on SKSB of CFWs and group-level construction safety management, the findings can improve safety communication among CFWs. [ABSTRACT FROM AUTHOR]

This paper presents the methods used and a case study of a project management system (PMS) to manage daily progress in the construction of multiple apartment buildings in South Korea. A dilemma encountered in previous research in the field of progress management is that efforts to enhance data accuracy cause the data handling workload to soar. A main feature of the method presented by the writers for calculating the budgeted cost work schedule is to allocate the project budget into control attributes, activities, and tasks that are defined in a work-packaging model, according to daily weight value. The method offers enhanced practicability by reducing data-handling workloads while not sacrificing the rationale of progress management. The work-packaging model is designed to enable project managers to acquire and process data for progress management at various levels of detail. The budgeted cost of work performed is measured daily at the tasks level using the earning percentage rate from daily work reports. The implementation of PMS focuses on functions to distribute the budget according to daily weight values and acquire the earning percentage from the daily work report. The PMS was applied to a construction project of 54 apartment buildings in South Korea. The case study of its use shows that company headquarters and managers in the field can acquire data for progress management without additional data-handling workloads, and can analyze the progress daily at various levels of detail. [ABSTRACT FROM AUTHOR]

This paper describes the results of a model testing of the piles embedded in Nak-Dong River sand, located in south Korea, under monotonic lateral loadings. A number of features were studied, including the lateral resistance of piles, the effect of the installation method, and the pile head restraint condition. The study has led to recommendations of the load–transfer curves (p–y curves) for laterally loaded piles. Modification factors were developed to allow for both a different pile installation method and different pile head restraint conditions by comparison to existing model load tests. The proposed p–y curves were compared to the existing curves and were evaluated with the experimental data. The ultimate lateral soil resistance and subgrade modulus were investigated and discussed. It is revealed that the proposed p–y curves show significant differences in shapes and magnitudes when compared with existing p–y curve models. The accuracy of the proposed p–y curve model, considering the effect of installation method and pile head restraint condition, is very reasonable as shown by comparing measured and predicted lateral behavior of the pile. [ABSTRACT FROM AUTHOR]

During negotiations in the initial stage of multinational megaprojects, technical issues are underemphasized compared to diplomatic or political perspectives despite varying relevant standards of participating countries. If the organization structures are established soundly while overcoming heterogeneous aspects of involved countries, decision making among countries satisfying both could be made timely and properly. With the aim of positive multilateral relationships and negotiations concerning engineering factors collectively, a framework is presented for identifying the roles and responsibilities of multinational joint clients with a hierarchical organization structure composed of a decision maker, senior responsible owner, project sponsor, and project manager. US forces relocation program in the Republic of Korea, a $1.4 billion megaproject, was analyzed where political and cultural aspects were attempted to melt down in a hierarchical organization. Results from interviewing high-level decision makers from both countries show that upper-level participants focus on political issues, while lower-level practitioners aim to achieve satisfactory technical quality. The involvement of engineers in earlier negotiation stages with upper-level counterparts is essential in establishing realistic goals. The uniqueness of the framework compared to previous factor-driven perspectives between different joint-client structures are as follows: Identical hierarchy of level from the countries supports defining roles with integrated scope management, and neutral consultative body for arbitrating conflict between countries and in-house departments within a country is required. [ABSTRACT FROM AUTHOR]

An earthquake of moment magnitude 5.4 occurred in Pohang, South Korea on November 15, 2017. This earthquake of moderate magnitude induced failures of structures and buildings and led to ground displacements. Approximately 600 sand boils were observed in the vicinity of the epicenter. We conduct 26 multichannel analysis of surface waves (MASW) tests and obtain three shear wave velocity (VS) profiles from suspension Compression (P) and Shear (S) wave logging at liquefied and nonliquefied sites near the epicenter. The phase velocities at frequencies lower than 10 Hz at the liquefied sites were smaller than those at the nonliquefied sites. The cyclic stress ratios (CSRs), cyclic resistance ratios (CRRs), and factors of safety were calculated. The CRR curves for these approaches predicted sand boils in Pohang with an accuracy of 79.5%. The liquefaction potential index (LPI) was calculated at 29 sites and is geospatially interpolated to create maps near the epicenter. The LPI maps had a maximum accuracy of 77% when LPI thresholds were 8 and 2 for two approaches from the literature. The high accuracies from both local and regional liquefaction evaluations demonstrate the applicability of the existing approaches for moderate earthquakes in South Korea. [ABSTRACT FROM AUTHOR]

This study analyzes in detail the information requirements for managing higher education facilities by building information modeling (BIM). This is achieved by conducting a job shadowing quarterly for a year, a document content analysis of facility management (FM) documents, expert interviews, and a comparative analysis of the FM information obtained from two universities each in the US and South Korea. The comparative analysis involves mapping the information requirements specified in different formats from the construction operations building information exchange (COBie) data format. The analysis reveals that although there are certain differences between the information required in the US and South Korea, most of the FM information requirements (83.4%, 136 items) can still be supported by COBie. The remainder of the unsupported information (16.6%, 27 items) is ignorable because it is associated with the information only acquirable during the FM phase and cannot be supported by the BIM handover or COBie. This finding increases the possibility of mandating COBie as data requirements for higher education facilities in extended regions. [ABSTRACT FROM AUTHOR]

Examines a method for estimating carbon dioxide emissions given off over the entire life cycle of various types of residential buildings in Korea. Four stages of the life cycle of a residential building; Carbon dioxide emissions in each life cycle stage; Inventory analysis that quantifies carbon dioxide emissions generated from manufacturing of building materials to demolition; Cause of carbon dioxide emissions.

Renovation and maintenance of heritage buildings to establish the cultural credibility of a country is an essential national task. To protect and maintain these structures, study of rehabilitation and strengthening methods for historical unreinforced masonry buildings has been a topic of experimental research. In Korea, significant historical structures made of granite stone require strengthening due to external destructive effects and internal degradation. Exposure to the elements has had an impact on granite stone resistance, resulting in separation and fracturing. To enhance structural behavior, pinning renovation techniques are essential. In this study, reinforcement by use of titanium bars was proposed as an effective method to improve the flexural strength of interconnected granite stones, which were applied in the restoration of Mireuksaji stone pagoda. Twenty specimens reinforced with titanium bars and epoxy resin were prepared, and a wide range of experiments were performed to determine strength performance of the structure based on various parameters. To provide a preliminary design guideline for reinforced epoxy-jointed granite segments, based on the current common practice in the design of concrete structures, failure of the specimens was classified as brittle or ductile. The results showed that adequate reinforcement following the proposed method can significantly enhance strength and ductility of the member. [ABSTRACT FROM AUTHOR]

Fire safety on building construction sites as an important part of on-site safety management has rarely been studied for construction sites. To fill the knowledge gap, this research was conducted to identify important influencing factors on fire safety on construction sites, as well as their relationships, through a questionnaire administered to 1,492 fire officers in South Korea. The authors divided the questions into three factors (building, fire, and human) to distinguish factors affecting construction site fire safety. For the majority of the factors, there was high agreement on the importance level of factors affecting fire safety during construction between administrative and field firefighters. However, perception disparity did exist. The authors identified the interrelationships between factors through path analysis and structural equation modeling. The paths of factors showed the highest direct relation between building and fire factors, and the human factor played a mediator role between human and fire factors. The study contributes to the overall body of knowledge by providing officers' insights into the factors contributing to fire safety on construction sites, as well as the quantification of the interrelationship among the factors, which will serve as the basis to develop effective safety measures, such as policies and regulations at both the project level and industry level, to address fire safety on construction sites. The SEM model developed in this study can also be used as a base model for future related studies. [ABSTRACT FROM AUTHOR]

Drought is among the most hazardous climatic disasters that significantly influence various aspects of the environment and human life. Qualitative and reliable drought forecasting is important worldwide for effective planning and decision-making in disaster-prone regions. Data-driven models have been extensively used for drought forecasting, but due to the inadequacy of information on model performance, the selection of an appropriate forecasting model remains a challenge. This study concerns a comparative analysis of six machine learning (ML) techniques widely used for hydrological drought forecasting. The standardized runoff index (SRI) was calculated at a seasonal (3-month) time scale for the period 1973 to 2016 in four selected watersheds of the Han River basin in South Korea. The ML models employed were built-ins, using precipitation, temperature, and humidity as input variables and the SRI as the target variable. The results indicated that all the ML models were able to map the relationship for seasonal SRI using the applied input vectors. The decision tree (DT) technique outperformed in all the watersheds with an average mean absolute error (MAE)=0.26 , root mean square error (RMSE)=0.34 , Nash-Sutcliffe efficiency (NSE)=0.87 , and coefficient of determination (R2)=0.89. The performances of the support vector machine (SVM) and deep learning neural network (DLNN) were similar, whereas the fuzzy rule-based system (FRBS) performed very well compared to the artificial neural network (ANN) and the adaptive neuro-fuzzy inference system (ANFIS). The overall findings of this study indicate that, considering performance criteria and computation time, the DT was the most accurate ML technique for hydrological drought forecasting in the Han River basin. [ABSTRACT FROM AUTHOR]

High-rise building projects (HRPs) are comprised of various complex design elements. The involvement of a multinational design team increases design-related issues for contractors, which must be managed during the construction stage. Thus, contractors need to understand how appropriate design management can positively affect project performance and their profit. Identification of critical design management factors (CDMFs) can provide appropriate decision-making support for contractors, including how limited resources including money, manpower, and equipment can be allocated throughout the construction stage. This study identifies and ranks the CDMFs for HRPs designed by multinational design teams. Through a questionnaire survey in South Korea, 21 design management factors were acknowledged among 40 initial factors. Then, using factor analysis, these 21 identified CDMFs were categorized into four groups: interface management, design information, production stage, and risk contribution. Based on results, this study identifies general and regional features of design management. Because these CDMFs are chosen from the contractor's perspective, if they are used to make appropriate decisions, the overall project performance should be increased during the construction phases. [ABSTRACT FROM AUTHOR]

A recent study reported that the construction management market has grown more competitive. In this environment, identifying a company's competitive position enables a study of competitor strategies and the ability to select the most suitable path to profitability. This study suggests a methodology to analyze topological competiveness based on social relationships between firms modeled according to four subnetworks: Joint contract networks linked directly between firms, public and private networks linked indirectly by owners, and building and civil networks linked indirectly by work type. This study proposes an analytical framework measuring topological competiveness from four perspectives: The network topology among each subnetwork, centralities and structural positions among the firms, cohesive subgroups and strong relations in the subnetwork, and the structural equivalence among firms. Using 2,984 cases of Korean construction management projects from 1997 to 2013, an empirical analysis of topological competiveness validated the methodology to diagnose competitiveness and select the most suitable relationships with competitors to create company growth. [ABSTRACT FROM AUTHOR]

The objective of this study is to assess stable irrigation water capacity and erosion on the basis of water and sediment balance analysis of land use change. The reservoir water balance analysis is calculated by the daily irrigation reservoir operation model (DIROM) for simulating daily inflow and release rates for irrigation reservoirs. The reservoir capacity change for assessing the sediment flux is predicted using the universal soil loss equation (USLE), sediment delivery ratio (SDR), and trap efficiency. To analyze soil erosion changes according to land use changes, Landsat-5 images were selected. Spatial distribution of deposited sediment is estimated by the U.S. Bureau of Reclamation (USBR) method and the hydrodynamic, sediment and contaminant transport model (HSCTM-2D), which is a finite-element model for simulating surface water flow and sediment transport. The model performance was verified by comparing simulated and observed data. The simulated results, which were validated using an internal mass balance method because of the scarce observed data, showed that the soil erosion of the Lake Asan watershed has increased at a rate of 2% per year from 1986 to 2000, and the storage capacity after 50 years will decrease by 65% without proper sediment conservation implementation. It is necessary to maintain stable irrigation water capacity by appropriate management of reservoir rehabilitation. The annual dredge amount was determined by various dredge scenarios according to the sediment removal volumes using frequency analysis. This approach will be useful for managers to identify the location and amount in which sediment dredging would be best for stable irrigation water supply maintenance. [ABSTRACT FROM AUTHOR]

Case-based reasoning (CBR) utilizes old solutions to solve a present problem. However, as no past situation is ever exactly the same as a new one, old solutions should be fitted for new circumstances, which is called case adaptation. Thus, the success of CBR depends on the ability of case adaptation. Generally, the case adaptation method can be categorized by two methods: decreasing the need for adaptation and increasing the capability. Nevertheless, previous research has focused on applying the method itself and rarely examined the adaptation or candidates selection. As an effort to enhance the performance of CBR, this research develops a case adaptation method that is balanced for both methods. To validate the method, a CBR cost model was developed that has an adaptation function using 129 military barrack projects in Korea, and then the method was tested by using 13 test cases. Furthermore, an applicability test was conducted based on 164 Korean public apartment projects. [ABSTRACT FROM AUTHOR]

Wetting depth in a slope is an important indicator to properly evaluate the rainfall-induced slope instability. This rainfall infiltration has potential to induce shallow slope failures. It is necessary to characterize the field infiltration and movement of the wetting front due to a natural rainfall. To monitor important infiltration characteristics of a field slope, a compacted roadside slope in an express highway (South Korea) was instrumented to measure variations of matric suction and water content. The monitored variations of matric suction and water content in vegetated and nonvegetated areas are discussed. The pattern of field infiltration by severe rainfall storms is also compared with the estimation results obtained by widely used 1D infiltration models. The Chu model, by considering the ponding and run-off at each time interval, showed a good agreement with the field measurements. [ABSTRACT FROM AUTHOR]

The development of strain in two 31 and 56 m long instrumented postdriving grouted cylinder piles at a site west of Busan, South Korea, were monitored during 200 days after construction, whereupon a static loading test was performed. Initial strain measurements showed unexpected elongation of the pile, probably due to swelling from absorption of water but as the soil reconsolidated, the elongation changed into shortening, probably due to imposed residual load in the pile. The resulting compression of the pile eventually offset the swelling of the pile. To investigate the cause of the strain changes more closely and enhance the evaluation of the field data, two short pile pieces were prepared and placed free-standing above ground in an outside laboratory. One piece was from a cylinder pile of which central void was grouted and one was made up by grouting inside a temporary casing. The monitoring showed that the short pieces appeared first to shorten and then to elongate due to the heating and cooling from the hydration process. When strains and temperature had stabilized 150 days after start of the study, both pieces were submerged to introduce swelling of the concrete. For the first 100 days after submerging, the swelling strains in both short pieces amounted to 100 μ[variant_greek_epsilon]. Seven hundred days after submersion, the total swelling strains were 150 and 250 μ[variant_greek_epsilon]. [ABSTRACT FROM AUTHOR]

Based on water chemistry data, a rockfill dam in South Korea was investigated to identify major parts of substantial dam water leakage. Sinkholes in the dam crest and abnormal water leakage through the dam were observed since the first impounding of the dam. Previous investigations, including observational drillings, hydraulic tests, geophysical surveys, and tracer tests, revealed the development of a high permeability zone in the clay core and an abnormally high phreatic line zone in the left embankment. Sequential tracer tests provided further evidence of locations of preference and rapid water leakage pathways. In this study, we examined the usefulness of water chemistry data to confirm previous findings of water leakage. Factor analysis of the water chemistry data revealed major processes controlling the chemical composition, which include the wash-out and successive dissolution of fill materials in the dam interior, interaction between percolating water and dam core materials, and contamination of seeping water by grouting materials and previous tracer tests. Distinct spatial distribution of similar chemical groups was illustrated by cluster analysis and confirmed the location of major water leakage at the left abutment adjoining the spillway. [ABSTRACT FROM AUTHOR]

Modern buildings and civil structures are complex undertakings and involve the use of a great variety of engineering methods and processes. Therefore most projects face the possibility of defects and defective work, which generally result in structures that cannot perform their originally intended roles. The characteristics of the contractor’s liabilities for defects are very controversial in Korea. There are two conflicting theories and one compromise between the two, concerning defect liabilities. One is liability in terms of the law, and the other is that in terms of the contract. These two kinds of liability are significantly different, varying in definition, scope of responsibility, period of responsibility, and other aspects. The purpose of this study is to suggest how to resolve potential disputes which might result from these differences through the analysis of current laws and their interpretation. [ABSTRACT FROM AUTHOR]

Proposes the application of nonshored top-down (NSTD) formwork system to building constructions in Seoul, South Korea. Excavation safety by the rigid diaphragm walls; Sufficient workspace for excavating under suspended forms during concrete curing; Reduction of excavation time; Improvement in underground concrete works; Cost-effectiveness of NSTD.