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Sunkuk Kim

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Papers by Sunkuk Kim

A Health Performance Evaluation Model of Apartment Building Indoor Air Quality

Indoor and Built Environment, Jan 10, 2011

As illnesses attributable to deteriorating indoor air quality (IAQ) increase, people are becoming... more As illnesses attributable to deteriorating indoor air quality (IAQ) increase, people are becoming more aware of the health effects of IAQ because most people in Korea spend &gt;80% of their time indoors. Notably, the IAQ of apartment buildings accounts for a massive share of the construction volume in Korea, which is a highly critical issue. Evaluation of health effects of IAQ would influence not only the statutory criteria for air quality improvement but could also contribute to the development of building design standards. In addition, such evaluation supports quantification efforts for the selection of wholesome construction materials and techniques. Evaluation of the health effects of IAQ is a complex exercise that would require comprehensive consideration of factors such as the concentrations and occurrences of various known, harmful indoor pollutants, ventilation performance in a building and temperature/humidity. Evaluation involves not only quantitative assessment of pollutants but also evaluation of IAQ based on human perception. The aim of this study was to develop a model to evaluate IAQ in quantitative terms based on health impact, but with an emphasis on apartment buildings.

Production Planning of Free-form Concrete Panels using 3D Plastering Technology

Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering, Oct 1, 2020

A technology has been developed to produce low-cost high-quality FCP (free-form concrete panel) u... more A technology has been developed to produce low-cost high-quality FCP (free-form concrete panel) using materials such as glass and pulp. However, FCP production and installation should meet required schedules in order for such technological development to be applied in practice. If it is not possible for the production to satisfy the installation schedules, sufficient lead time should be granted; otherwise, an additional 3D plastering machine is required. This then would give rise to cost and time conflicts. Therefore, an analysis on processes and influential factors relating to FCP production-installation is necessary after which algorithms should be created to link these processes and factors in a systematic method. This study is aimed at production planning of free-form concrete panels using 3D plastering technology. For the purpose of this study, an influential factor analysis and production planning shall be performed in a phased approach. The results of this study are expected to be used as a crucial reference in developing models that can simulate FCP productioninstallation in various ways.

Miscibility of Solution Blends of Unsaturated Polyester Resin with Polystyrene and Polycarbonate

Journal of Macromolecular Science, Part B, Jun 11, 2010

ABSTRACT Miscibility studies of unsaturated polyester resin (UPR) blends with two different therm... more ABSTRACT Miscibility studies of unsaturated polyester resin (UPR) blends with two different thermoplastics—polystyrene (PS) and polycarbonate (PC), in a common solvent, chloroform, were carried out by viscosity, ultrasonic velocity, density, and refractive index methods. Two interaction parameters, μ and α were calculated using viscosity data for these blends. The positive interaction parameter values (μ and α &gt; 0) obtained for the UPR/PS blend and the negative interaction parameter values (μ and α &lt; 0) obtained for the UPR/PC blend indicate that the former is a miscible blend and the latter is an immiscible blend. These results were further confirmed by the ultrasonic velocity, density, and refractive index measurements.

Decision Factors on Free-form Concrete Panel Sizes Produced by CNC Machines

Proceedings of the Korean Institute of Building Construction Conference, 2015

Load carrying capacity of Structural Composite Hybrid System (Green Frame)

KIEAE Journal, 2010

Cost and CO2 Analysis of Composite Precast Concrete Columns

Springer eBooks, 2013

Green Frame is developed not only to reduce costs and construction duration and improve safety an... more Green Frame is developed not only to reduce costs and construction duration and improve safety and constructability, but also to enhance environmental-friendliness resulting from reduction of CO2 emission. Green Frame is a column-beam system composed of the Green Column and Green Beam, which are the composite precast concrete members. There are 5 types of Green Columns with different cost required and CO2 emission. The importance of cost and CO2 emission varies depending on the characteristics of a given project. Thus, this research is intended to perform cost and CO2 analysis in order to help engineers select the most appropriate Green Column type. As a result, it is drawn out that a specific type is not superior in all aspects. If a wide range of performances including productivity, constructability, construction safety and construction period are analyzed in the future, it will be likely to suggest a meaningful guideline to engineers in selecting a suitable Green Column for Green Frame.

The Application of MHS Frames for Apartments of Extended Life in Korea

Han'gug geonseol si'gong haghoeji, Dec 20, 2008

Measuring Safety Climate in the Construction Industry: A Systematic Literature Review

Sustainability, Sep 24, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

Thermal and Mechanical Properties of Epoxy/Carbon Fiber Composites Reinforced with Multi-walled Carbon Nanotubes

Journal of Macromolecular Science, Part B, Aug 11, 2011

Multi-scale hybrid composite laminates of epoxy/carbon fiber (CF) reinforced with multi-walled ca... more Multi-scale hybrid composite laminates of epoxy/carbon fiber (CF) reinforced with multi-walled carbon nanotubes (MWCNTs) were fabricated in an autoclave. For laminate fabrication, 0.5 wt% of pristine MWCNTs or silane-functionalized MWNCTs (f-MWCNTs) were dispersed into a diglycidyl ether of bisphenol-A epoxy system and applied on the woven carbon fabric. The neat epoxy/CF composite and the MWCNTs-reinforced epoxy/CF hybrid composites were characterized by thermogravimetric analysis (TGA), thermomechanical analysis (TMA), tensile testing, and field emission scanning electron microscopy (FE-SEM). A significant improvement in initial decomposition temperature and glass transition temperature of epoxy/CF composite was observed when reinforced with 0.5 wt% of f-MWCNTs. The coefficient of thermal expansion (CTE), measured by TMA, diminished by 22% compared to the epoxy/CF composite, indicating an improvement in dimensional stability of the hybrid composite. No significant improvement in tensile properties of either MWCNTs/epoxy/CF composites was observed compared to those of the neat epoxy/CF composite.

Planning and Monitoring the Tact of Work Flow

Proceedings of the ... ISARC, Sep 25, 2004

To ensure a continuous and smooth work flow, this research proposes (1) Tact Scheduling Method as... more To ensure a continuous and smooth work flow, this research proposes (1) Tact Scheduling Method as an alternative to traditional ones and (2) Work Flow Monitoring System (WFMS). Tact scheduling is intended to balance the unit activities of relevant work trades in terms of the duration and the labor input required for performing each activity. Subcontractors as well as the main contractor participate in the planning stage and adjust the same duration and the labor input for every unit activity by zoning the workspace. Prior to developing the WFMS, a few factors that are considered to possibly affect the variation of the work flow are defined and indicators to measure these factors are devised.

Sustainable Decommissioning Strategies for Nuclear Power Plants: A Systematic Literature Review

Sustainability, May 13, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more

Embodied CO2 Reduction Effects of Composite Precast Concrete Frame for Heavily Loaded Long-Span Logistics Buildings

Sustainability, Jan 20, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

A Solution of Subordinate Vertices for Quality Connections of External Free-Form Concrete Panels

Journal of Civil Engineering and Management, Sep 11, 2018

3D-designs of free-form buildings are developed using a computer due to difficulty of shape imple... more 3D-designs of free-form buildings are developed using a computer due to difficulty of shape implementation. When producing free-form concrete panel (FCP) using materials such as GFRC (glass fiber reinforced concrete), engineers or manufacturers should precisely calculate the offset value or geometry of each member at the junction point of three or more FCPs before it is constructed. However, it is difficult to calculate offset geometry easily and quickly, and no research has been conducted on this topic. Therefore, the objective of this paper is to develop a solution of subordinate vertices for quality connections of external free-form concrete panels. The developed mathematical solutions practically support the production of FCPs with precise installation to ensure aesthetic quality of the building. This paper academically contributes to the automatic creation of joint details of FCPs implemented by BIM.

A Competitive Advantage Analysis of Construction Duration through the Comparison of Actual Data of Domestic Construction Firms - Focused on Mix-Use Residential Building and Officetel Building

Korean Journal of Construction Engineering and Management, 2006

Construction companies have been interested in the construction duration which importantly affect... more Construction companies have been interested in the construction duration which importantly affects the performance and the success of the construction projects in accordance with the systemic changes such as five days per week system, introduction of construction duration reduction bidding system and post sale system nowadays. It is also very important to estimate and forecast properly the construction duration as the construction companies compete for the projects in the situation of construction market reduction and the lowest bidding system. Recognizing the importance about the construction duration, the researches about comparing and analyzing or estiamting the construction duration have been performed. However, comparing studies about the construction duraion have been limited to the apartment and office building in domestic area. Many studies about forecasting construction duration have been performed through stochastic analysis and simulations. Little research has been addressed the comparison analysis of the real construction duration about the mix-use building and officetel building which occured according to the changes of the building requirements. Therefore, the objective of this study is to compare and analyze the real construction duration and the hypothetical construction duration about the mix-use building and officetel building of the domestic companies. Moreover, we select the most competitve construction company to get the strengths and analyze the competitive advatages of the construction companies about construction duration.

Mathematical Algorithms of Patterns for Free-Form Panels

Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering, Apr 1, 2017

Free-Form buildings provide a wide range of diverse and beautiful spaces supported by the develop... more Free-Form buildings provide a wide range of diverse and beautiful spaces supported by the development of digital technology. However, there are many difficulties and challenges in realizing free-form curved surfaces at the design and construction phase. Accordingly, panelizing of most free-form buildings is performed only in consideration of reducing the construction cost, or constructability. This panelizing process results in curved surfaces that are against the designer's intention, and this makes it difficult for the designers to come up with the planned beauty. This may happen because the process of designing a free-form building differs from that of a specifically-formed building, and it is difficult to mathematically define the curved surfaces designed. Thus, the purpose of this study is to define mathematical algorithms of patterns for finish panels of free-form buildings based on the basic principles of building design forms such as repetition and gradation. The study results will be used to mathematically review various methods of dividing curved surfaces at the initial design phase of actual free-form building projects, as well as to automatically extract accurate production information and to respond to technical problems that may arise in the construction process.

Risk Analysis of the In Situ Production of Precast Concrete Members

Lecture notes in civil engineering, May 13, 2018

The precast concrete (PC) method has been preferred for reasons of shortening of construction tim... more The precast concrete (PC) method has been preferred for reasons of shortening of construction time, quality assurance, and cost reduction. In addition, in situ production of PC members under equivalent production conditions can save costs while ensuring quality equal to or better than in-plant production. Despite these advantages, in situ production is being avoided due to possible risks from project management. Therefore, in order to generalize the in situ production of PC members, it is necessary to clarify the causes of the possible risks and establish responses. Therefore, the purpose of this study is to analyse the in situ production risks of PC members. The results of this study can be used to establish a systematic response plan for possible risks in the in situ production of PC members.

A Health Performance and Cost Optimization Model for Sustainable Healthy Buildings

Journal of Asian Architecture and Building Engineering, May 1, 2017

To construct a sustainable and healthy building, it is necessary to build a system capable of eff... more To construct a sustainable and healthy building, it is necessary to build a system capable of efficiently analyzing, assessing and managing health performance data over the life cycle of a building. To fulfill such needs, health-friendly resources database, life cycle health-performance tree, health performance evaluation and health management concepts were suggested. Such studies focused on health performance. Selecting building materials based only on their health performance while ignoring cost is likely to lead to not only rapid construction cost increases, but also higher maintenance costs. For cost-benefit management, the health performance and cost management model was proposed. However, while the model can be used in decisionmaking, it is unable to suggest an optimization solution. To supplement this need, this study proposes a health performance and cost optimization model for sustainable healthy buildings. The model proposed here is composed of simulation and optimization modules for health performance and cost using the concepts mentioned above.

Composite beam composed of steel and precast concrete (modularized hybrid system). Part IV: Application for multi-residential housing

Structural Design of Tall and Special Buildings, 2009

Multi‐residential bearing wall apartments have been constructed to meet the needs of the populati... more Multi‐residential bearing wall apartments have been constructed to meet the needs of the population growth in metropolitan Korea since 1980. It is extremely difficult to remodel wall‐type multi‐residential apartments due to the nature of the bearing walls. Residents also experience noise and vibrations generated between floors. It is necessary to introduce a frame structure that enables easy remodelling for the realization of long life of apartment. This paper introduces an efficient, multi‐residential modularized hybrid system (MHS). The material quantities, material cost and amount of CO2 emission for the MHS are compared to that of bearing wall structures (linear rectangular shape and tower shape) and flat slab structures. A multi‐residential apartment with an MHS composite girder ensures architectural plan flexibility and easy remodelling, while the floor heights are maintained at the same floor height as in bearing wall structures. The material cost of MHS multi‐residential housing can be reduced by reducing the amount of concrete and reinforcement steels required for the slabs and walls. The MHS also reduces CO2 emission in accordance with the reduction of construction materials. Dry‐type construction can be environment friendly by reducing human resources, temporary materials and waste. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Mathematical Model of Hybrid Precast Gravity Frames for Smart Construction and Engineering

Mathematical Problems in Engineering, 2014

The structural stability, constructability, economic feasibility, environmental-friendliness, and... more The structural stability, constructability, economic feasibility, environmental-friendliness, and energy efficiency of hybrid composite frame systems have been demonstrated by practical application and research. A hybrid composite frame system combines the economy of precast concrete structures with the constructability of steel frame structures, including erection speed. Novel composite frames will ultimately maximize the efficiency of structural design and facilitate construction. This paper presents hybrid precast frames, which are precast composite frames based on a simple connection between precast concrete columns and beams. The hybrid precast frames designed to resist gravity loading consist of PC columns, PC beams, and steel inserted in the precast members. Steel sections located between the precast columns were simply connected to steel inserted at each end of the precast beams. Dynamic analysis of a 15-story building designed with the proposed composite frame was performed to determine the dynamic characteristics of a building constructed of hybrid frames, including frequencies and mode shapes.

Development of a Steel-Guide Connection Method for Composite Precast Concrete Components

Journal of Civil Engineering and Management, Jul 1, 2016

Green Frame is a column-beam structure formed by connecting a composite precast concrete beam wit... more Green Frame is a column-beam structure formed by connecting a composite precast concrete beam with a steel connection on the column side. Similar to steel frame construction, the green columns cover 3 stories per unit, and generate vertical and horizontal eccentricities due to construction errors and the gravitational loads of beams. Such eccentricities make it difficult to install the upper floor beams and adjacent frames. This problem not only results in decreased productivity, but also in time delays and cost overrun. The objective of this study is to develop a new steelguide connection method for composite precast concrete (CPC) components after analysing the erection process and structural mechanism to resolve eccentricity issues. The connection mechanism developed in this study resolves these eccentricities and promotes efficient, accurate, and safe construction.

A Health Performance Evaluation Model of Apartment Building Indoor Air Quality

Indoor and Built Environment, Jan 10, 2011

As illnesses attributable to deteriorating indoor air quality (IAQ) increase, people are becoming... more As illnesses attributable to deteriorating indoor air quality (IAQ) increase, people are becoming more aware of the health effects of IAQ because most people in Korea spend &gt;80% of their time indoors. Notably, the IAQ of apartment buildings accounts for a massive share of the construction volume in Korea, which is a highly critical issue. Evaluation of health effects of IAQ would influence not only the statutory criteria for air quality improvement but could also contribute to the development of building design standards. In addition, such evaluation supports quantification efforts for the selection of wholesome construction materials and techniques. Evaluation of the health effects of IAQ is a complex exercise that would require comprehensive consideration of factors such as the concentrations and occurrences of various known, harmful indoor pollutants, ventilation performance in a building and temperature/humidity. Evaluation involves not only quantitative assessment of pollutants but also evaluation of IAQ based on human perception. The aim of this study was to develop a model to evaluate IAQ in quantitative terms based on health impact, but with an emphasis on apartment buildings.

Production Planning of Free-form Concrete Panels using 3D Plastering Technology

Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering, Oct 1, 2020

A technology has been developed to produce low-cost high-quality FCP (free-form concrete panel) u... more A technology has been developed to produce low-cost high-quality FCP (free-form concrete panel) using materials such as glass and pulp. However, FCP production and installation should meet required schedules in order for such technological development to be applied in practice. If it is not possible for the production to satisfy the installation schedules, sufficient lead time should be granted; otherwise, an additional 3D plastering machine is required. This then would give rise to cost and time conflicts. Therefore, an analysis on processes and influential factors relating to FCP production-installation is necessary after which algorithms should be created to link these processes and factors in a systematic method. This study is aimed at production planning of free-form concrete panels using 3D plastering technology. For the purpose of this study, an influential factor analysis and production planning shall be performed in a phased approach. The results of this study are expected to be used as a crucial reference in developing models that can simulate FCP productioninstallation in various ways.

Miscibility of Solution Blends of Unsaturated Polyester Resin with Polystyrene and Polycarbonate

Journal of Macromolecular Science, Part B, Jun 11, 2010

ABSTRACT Miscibility studies of unsaturated polyester resin (UPR) blends with two different therm... more ABSTRACT Miscibility studies of unsaturated polyester resin (UPR) blends with two different thermoplastics—polystyrene (PS) and polycarbonate (PC), in a common solvent, chloroform, were carried out by viscosity, ultrasonic velocity, density, and refractive index methods. Two interaction parameters, μ and α were calculated using viscosity data for these blends. The positive interaction parameter values (μ and α &gt; 0) obtained for the UPR/PS blend and the negative interaction parameter values (μ and α &lt; 0) obtained for the UPR/PC blend indicate that the former is a miscible blend and the latter is an immiscible blend. These results were further confirmed by the ultrasonic velocity, density, and refractive index measurements.

Decision Factors on Free-form Concrete Panel Sizes Produced by CNC Machines

Proceedings of the Korean Institute of Building Construction Conference, 2015

Load carrying capacity of Structural Composite Hybrid System (Green Frame)

KIEAE Journal, 2010

Cost and CO2 Analysis of Composite Precast Concrete Columns

Springer eBooks, 2013

Green Frame is developed not only to reduce costs and construction duration and improve safety an... more Green Frame is developed not only to reduce costs and construction duration and improve safety and constructability, but also to enhance environmental-friendliness resulting from reduction of CO2 emission. Green Frame is a column-beam system composed of the Green Column and Green Beam, which are the composite precast concrete members. There are 5 types of Green Columns with different cost required and CO2 emission. The importance of cost and CO2 emission varies depending on the characteristics of a given project. Thus, this research is intended to perform cost and CO2 analysis in order to help engineers select the most appropriate Green Column type. As a result, it is drawn out that a specific type is not superior in all aspects. If a wide range of performances including productivity, constructability, construction safety and construction period are analyzed in the future, it will be likely to suggest a meaningful guideline to engineers in selecting a suitable Green Column for Green Frame.

The Application of MHS Frames for Apartments of Extended Life in Korea

Han'gug geonseol si'gong haghoeji, Dec 20, 2008

Measuring Safety Climate in the Construction Industry: A Systematic Literature Review

Sustainability, Sep 24, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

Thermal and Mechanical Properties of Epoxy/Carbon Fiber Composites Reinforced with Multi-walled Carbon Nanotubes

Journal of Macromolecular Science, Part B, Aug 11, 2011

Multi-scale hybrid composite laminates of epoxy/carbon fiber (CF) reinforced with multi-walled ca... more Multi-scale hybrid composite laminates of epoxy/carbon fiber (CF) reinforced with multi-walled carbon nanotubes (MWCNTs) were fabricated in an autoclave. For laminate fabrication, 0.5 wt% of pristine MWCNTs or silane-functionalized MWNCTs (f-MWCNTs) were dispersed into a diglycidyl ether of bisphenol-A epoxy system and applied on the woven carbon fabric. The neat epoxy/CF composite and the MWCNTs-reinforced epoxy/CF hybrid composites were characterized by thermogravimetric analysis (TGA), thermomechanical analysis (TMA), tensile testing, and field emission scanning electron microscopy (FE-SEM). A significant improvement in initial decomposition temperature and glass transition temperature of epoxy/CF composite was observed when reinforced with 0.5 wt% of f-MWCNTs. The coefficient of thermal expansion (CTE), measured by TMA, diminished by 22% compared to the epoxy/CF composite, indicating an improvement in dimensional stability of the hybrid composite. No significant improvement in tensile properties of either MWCNTs/epoxy/CF composites was observed compared to those of the neat epoxy/CF composite.

Planning and Monitoring the Tact of Work Flow

Proceedings of the ... ISARC, Sep 25, 2004

To ensure a continuous and smooth work flow, this research proposes (1) Tact Scheduling Method as... more To ensure a continuous and smooth work flow, this research proposes (1) Tact Scheduling Method as an alternative to traditional ones and (2) Work Flow Monitoring System (WFMS). Tact scheduling is intended to balance the unit activities of relevant work trades in terms of the duration and the labor input required for performing each activity. Subcontractors as well as the main contractor participate in the planning stage and adjust the same duration and the labor input for every unit activity by zoning the workspace. Prior to developing the WFMS, a few factors that are considered to possibly affect the variation of the work flow are defined and indicators to measure these factors are devised.

Sustainable Decommissioning Strategies for Nuclear Power Plants: A Systematic Literature Review

Sustainability, May 13, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more

Embodied CO2 Reduction Effects of Composite Precast Concrete Frame for Heavily Loaded Long-Span Logistics Buildings

Sustainability, Jan 20, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more

A Solution of Subordinate Vertices for Quality Connections of External Free-Form Concrete Panels

Journal of Civil Engineering and Management, Sep 11, 2018

3D-designs of free-form buildings are developed using a computer due to difficulty of shape imple... more 3D-designs of free-form buildings are developed using a computer due to difficulty of shape implementation. When producing free-form concrete panel (FCP) using materials such as GFRC (glass fiber reinforced concrete), engineers or manufacturers should precisely calculate the offset value or geometry of each member at the junction point of three or more FCPs before it is constructed. However, it is difficult to calculate offset geometry easily and quickly, and no research has been conducted on this topic. Therefore, the objective of this paper is to develop a solution of subordinate vertices for quality connections of external free-form concrete panels. The developed mathematical solutions practically support the production of FCPs with precise installation to ensure aesthetic quality of the building. This paper academically contributes to the automatic creation of joint details of FCPs implemented by BIM.

A Competitive Advantage Analysis of Construction Duration through the Comparison of Actual Data of Domestic Construction Firms - Focused on Mix-Use Residential Building and Officetel Building

Korean Journal of Construction Engineering and Management, 2006

Construction companies have been interested in the construction duration which importantly affect... more Construction companies have been interested in the construction duration which importantly affects the performance and the success of the construction projects in accordance with the systemic changes such as five days per week system, introduction of construction duration reduction bidding system and post sale system nowadays. It is also very important to estimate and forecast properly the construction duration as the construction companies compete for the projects in the situation of construction market reduction and the lowest bidding system. Recognizing the importance about the construction duration, the researches about comparing and analyzing or estiamting the construction duration have been performed. However, comparing studies about the construction duraion have been limited to the apartment and office building in domestic area. Many studies about forecasting construction duration have been performed through stochastic analysis and simulations. Little research has been addressed the comparison analysis of the real construction duration about the mix-use building and officetel building which occured according to the changes of the building requirements. Therefore, the objective of this study is to compare and analyze the real construction duration and the hypothetical construction duration about the mix-use building and officetel building of the domestic companies. Moreover, we select the most competitve construction company to get the strengths and analyze the competitive advatages of the construction companies about construction duration.

Mathematical Algorithms of Patterns for Free-Form Panels

Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering, Apr 1, 2017

Free-Form buildings provide a wide range of diverse and beautiful spaces supported by the develop... more Free-Form buildings provide a wide range of diverse and beautiful spaces supported by the development of digital technology. However, there are many difficulties and challenges in realizing free-form curved surfaces at the design and construction phase. Accordingly, panelizing of most free-form buildings is performed only in consideration of reducing the construction cost, or constructability. This panelizing process results in curved surfaces that are against the designer's intention, and this makes it difficult for the designers to come up with the planned beauty. This may happen because the process of designing a free-form building differs from that of a specifically-formed building, and it is difficult to mathematically define the curved surfaces designed. Thus, the purpose of this study is to define mathematical algorithms of patterns for finish panels of free-form buildings based on the basic principles of building design forms such as repetition and gradation. The study results will be used to mathematically review various methods of dividing curved surfaces at the initial design phase of actual free-form building projects, as well as to automatically extract accurate production information and to respond to technical problems that may arise in the construction process.

Risk Analysis of the In Situ Production of Precast Concrete Members

Lecture notes in civil engineering, May 13, 2018

The precast concrete (PC) method has been preferred for reasons of shortening of construction tim... more The precast concrete (PC) method has been preferred for reasons of shortening of construction time, quality assurance, and cost reduction. In addition, in situ production of PC members under equivalent production conditions can save costs while ensuring quality equal to or better than in-plant production. Despite these advantages, in situ production is being avoided due to possible risks from project management. Therefore, in order to generalize the in situ production of PC members, it is necessary to clarify the causes of the possible risks and establish responses. Therefore, the purpose of this study is to analyse the in situ production risks of PC members. The results of this study can be used to establish a systematic response plan for possible risks in the in situ production of PC members.

A Health Performance and Cost Optimization Model for Sustainable Healthy Buildings

Journal of Asian Architecture and Building Engineering, May 1, 2017

To construct a sustainable and healthy building, it is necessary to build a system capable of eff... more To construct a sustainable and healthy building, it is necessary to build a system capable of efficiently analyzing, assessing and managing health performance data over the life cycle of a building. To fulfill such needs, health-friendly resources database, life cycle health-performance tree, health performance evaluation and health management concepts were suggested. Such studies focused on health performance. Selecting building materials based only on their health performance while ignoring cost is likely to lead to not only rapid construction cost increases, but also higher maintenance costs. For cost-benefit management, the health performance and cost management model was proposed. However, while the model can be used in decisionmaking, it is unable to suggest an optimization solution. To supplement this need, this study proposes a health performance and cost optimization model for sustainable healthy buildings. The model proposed here is composed of simulation and optimization modules for health performance and cost using the concepts mentioned above.

Composite beam composed of steel and precast concrete (modularized hybrid system). Part IV: Application for multi-residential housing

Structural Design of Tall and Special Buildings, 2009

Multi‐residential bearing wall apartments have been constructed to meet the needs of the populati... more Multi‐residential bearing wall apartments have been constructed to meet the needs of the population growth in metropolitan Korea since 1980. It is extremely difficult to remodel wall‐type multi‐residential apartments due to the nature of the bearing walls. Residents also experience noise and vibrations generated between floors. It is necessary to introduce a frame structure that enables easy remodelling for the realization of long life of apartment. This paper introduces an efficient, multi‐residential modularized hybrid system (MHS). The material quantities, material cost and amount of CO2 emission for the MHS are compared to that of bearing wall structures (linear rectangular shape and tower shape) and flat slab structures. A multi‐residential apartment with an MHS composite girder ensures architectural plan flexibility and easy remodelling, while the floor heights are maintained at the same floor height as in bearing wall structures. The material cost of MHS multi‐residential housing can be reduced by reducing the amount of concrete and reinforcement steels required for the slabs and walls. The MHS also reduces CO2 emission in accordance with the reduction of construction materials. Dry‐type construction can be environment friendly by reducing human resources, temporary materials and waste. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Mathematical Model of Hybrid Precast Gravity Frames for Smart Construction and Engineering

Mathematical Problems in Engineering, 2014

The structural stability, constructability, economic feasibility, environmental-friendliness, and... more The structural stability, constructability, economic feasibility, environmental-friendliness, and energy efficiency of hybrid composite frame systems have been demonstrated by practical application and research. A hybrid composite frame system combines the economy of precast concrete structures with the constructability of steel frame structures, including erection speed. Novel composite frames will ultimately maximize the efficiency of structural design and facilitate construction. This paper presents hybrid precast frames, which are precast composite frames based on a simple connection between precast concrete columns and beams. The hybrid precast frames designed to resist gravity loading consist of PC columns, PC beams, and steel inserted in the precast members. Steel sections located between the precast columns were simply connected to steel inserted at each end of the precast beams. Dynamic analysis of a 15-story building designed with the proposed composite frame was performed to determine the dynamic characteristics of a building constructed of hybrid frames, including frequencies and mode shapes.

Development of a Steel-Guide Connection Method for Composite Precast Concrete Components

Journal of Civil Engineering and Management, Jul 1, 2016

Green Frame is a column-beam structure formed by connecting a composite precast concrete beam wit... more Green Frame is a column-beam structure formed by connecting a composite precast concrete beam with a steel connection on the column side. Similar to steel frame construction, the green columns cover 3 stories per unit, and generate vertical and horizontal eccentricities due to construction errors and the gravitational loads of beams. Such eccentricities make it difficult to install the upper floor beams and adjacent frames. This problem not only results in decreased productivity, but also in time delays and cost overrun. The objective of this study is to develop a new steelguide connection method for composite precast concrete (CPC) components after analysing the erection process and structural mechanism to resolve eccentricity issues. The connection mechanism developed in this study resolves these eccentricities and promotes efficient, accurate, and safe construction.