• Journal of Korean Society of Steel Construction
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• v.25 no.5
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• pp.519-530
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• 2013

Cyclic tests on modular building units for low-rise buildings composed of stud panels and a light-weight steel perimeter frame, were performed to evaluate the earthquake resistance such as stiffness, load-carrying capacity, ductility, and energy dissipation per load cycle. The strap-braced and sheeted stud panels were used as the primary lateral load-resistant element of the modular building units. Test results showed that the modular building units using the strap-braced and sheeted stud panels exhibited excellent post-yield ductile behaviors. The maximum drift ratios were greater than 5.37% and the displacement ductility ratios were greater than 5.76. However, the energy dissipation per load cycle was poor due to severe pinching during cyclic loading. Nominal strength, stiffness, and yield displacement of the modular building units were predicted based on plastic mechanisms. The predictions reasonably and conservatively correlated with the test results. However, the elastic stiffness of the strap-braced stud panel was significantly overestimated. For conservative design, the elastic stiffness of the strap-braced stud panel needs be decreased to 50% of the nominal value.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.809-820
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• 2023

In contemporary society, there is a notable rise in single-person households, coupled with an increased demand for residential spaces, necessitating the exploration of suitable housing solutions. Modular architecture is gaining prominence as a method to deliver cost-effective and sustainable living spaces efficiently. This study introduces a method for optimizing the design and construction processes of modular building units through Building Information Modeling(BIM) technology. It involves an analysis of factors that enhance living quality and meet the housing needs of single-person households. Utilizing BIM, a resource-efficient and cost-efficient modular apartment unit has been developed. BIM facilitates the visualization and integration of architectural components, thereby reducing design errors and enhancing productivity. This research evaluates both the benefits and constraints of modular architecture. Modular constructions, when combined with BIM, emerge as a potent solution for housing challenges, enriching the quality and variety of residential options. Nevertheless, considerations such as technical prerequisites and financial implications are also discussed. The study showcases the potential and merits of utilizing BIM for designing apartment units tailored to single-person households, offering a viable approach to ameliorate their living conditions.

• Journal of the Korean Mathematical Society
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• v.53 no.6
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• pp.1445-1457
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• 2016

For a positive integer N divisible by 4, let ${\mathcal{O}}^1_N({\mathbb{Q}})$ be the ring of weakly holomorphic modular functions for the congruence subgroup ${\Gamma}^1(N)$ with rational Fourier coefficients. We present explicit generators of the ring ${\mathcal{O}}^1_N({\mathbb{Q}})$ over ${\mathbb{Q}}$ in terms of both Fricke functions and Siegel functions, from which we are able to classify all Fricke families of such level N.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.113-114
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• 2012

The productivity of the construction industry is lower than other industries. Modular system is suggested to enhance the productivity of the construction industry. Modular system is a construction method which installs units manufactured in factory on site. It enables to reduce the duration and improve the quality of the constructions. However, the construction technique applied to modular system has not overcome certain structural problems. To solve the problems and motivate the application of modular system, this study propose the hybrid system which use core to resist a lateral force.

• Journal of Korean Association for Spatial Structures
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• v.22 no.3
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• pp.41-48
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• 2022

The purpose of this study is to evaluate seismic performances of a modular house system developed by a simple 4-clip fastening method and double metal assembly made of lightweight metals. In order to evaluate structural and non-structural seismic performances of the system. Shaking table test was carried out with full-scale modular units, and a nonlinear pushover analysis was performed to obtain suitable seismic responses for story drifts, displacements, force resistances and dynamic properties of the system. Through 3D analysis and shaking table test, the current method of lightweight modular metal unit assembly and systems with seismic performance of a 4-clip fastening type modular house were demonstrated safe and effective to seismic design.

• Korean Journal of Construction Engineering and Management
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• v.24 no.5
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• pp.63-72
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• 2023

This study investigates the virtual reality (VR) simulation to train construction workers for modular construction. Recently, the construction industry has been experiencing a growing demand for modular construction due to a shortage of labors and an increasing social need for safety. While the demand for modular construction has been increasing, construction labors suffer a basic knowledge regarding modular construction. The users of the simulation, developed by Unity program and Oculus Quest 2, experience the removal of hazardous elements at the location whether the modular unit suspended by a crane is lowered, the lowering and assembly of units through crane operation, and the fall from the roof which is the most frequent accidents in modular construction. The simulation was tested by 15 subjects. The effectiveness of the education was measured through a survey on self-efficacy, perceived usefulness, usability, and presence. It was found that the VR training is suitable for educating on the modular construction activities and safety issues related to them. This study also found that perceived usefulness is the factor that has the greatest impact on self-efficacy. This study can contribute to resolving the labor education issues for the deployment of modular construction.

• Journal of Korean Society of Steel Construction
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• v.28 no.6
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• pp.467-476
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• 2016

For the connections between modular units in modular buildings, the bolted joints with connector plates are used commonly. The strength of structure is determined by the weakest part of structure and the connections may be weaker than the members being joined. Therefore, to check the safety of modular building, the structural performance of connections between modular units as well as that of beam-to-column connections should be evaluated. In this study, the behavior of module to module connection with straight and cross shaped connector plates is investigated by lateral cyclic tests according to KBC2009 0722.2.4 which shall be conducted by controlling the story drift angle in the width and the longitudinal direction respectively. All of test results generally show the stable ductile behavior up to 0.04rad drift levels and the tests in longitudinal direction show a superior energy dissipation per cycle in each of the load steps. However, the straight shaped connector plates have the degradation of stiffness with cyclic loading and the larger drift angle of column than the cross shaped connector plates.

• Land and Housing Review
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• v.6 no.4
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• pp.231-237
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• 2015

Recently, It has been much interest in modular housing construction. so, The purpose of this study was to investigate the characteristics of the indoor air quality in modular mock-up housing. We measured indoor air quality(formaldehyde, benzene, toluene, ethylbenzene, xylene, styrene) of two modular mock-up units that built-in furniture is installed and uninstalled. As a result, the pollutants of built-in furniture installed unit were emitted more than built-in furniture uninstalled unit. But after bake-out and ventilation, emission concentrations of two modular mock-up units were similar and were below Indoor Air Quality recommendation standards. Built-in furniture is likely to affect the emission concentration of toluene

• Journal of Korean Society of Steel Construction
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• v.29 no.6
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• pp.435-442
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• 2017

A lateral load resisting system is a necessary structural element for the mid- to high-rise modular buildings and concrete cores are known as the most typical lateral load resisting systems in 10- to 20-story modular buildings. It is difficult to construct a concrete core simultaneously with the installation and finishing work of modular units because concrete placed using wet methods might contaminate or destroy the modular unit. Therefore, we have developed a hybrid PC (precast concrete) panel construction method that can construct a concrete core together with the installation of modular units. The hybrid PC panel is a load-bearing element in which a pair of C-shaped beams are combined at the top and bottom of a concrete wall. Concrete cores can be constructed by dry method to connect the hybrid PC panels with bolts. In this study, the details and connection of hybrid PC panels are improved to have the lateral performance comparable to reinforced concrete structural walls and are verified through FE analysis.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.4
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• pp.25-33
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• 2018

In regard to modular systems, new methods, as well as middle and high-story unit design ideas, are currently being studied. These studies need to focus on the enhanced stiffness and seismic performance of these connections, and see that the development of fully restrained moment connections can improve the seismic performance. For this reason, this study evaluates the performance of the connections of the ceiling bracket-typed modular system through repeated loading tests and analyses. In order to compare them with these modular units, new unit specimens with the bracket connection being different from that of the traditional modular unit specimens were designed, and the results of repeated loading tests were analyzed. In the traditional units, the structural performances of both welding connection and bolt connection were evaluated. In regard to the testing results, the initial stiffness of the hysteresis curve was compared with the theoretical initial stiffness, and the features of all specimens were also analyzed with regard to the maximum moment. In addition, the test results were examined with regard to the connection flexural strength of the steel special moment frame specified under the construction criteria KBC2016. The connections, which were proposed in the test results, were found to be fully restrained moment connections for designing strong column-weak beams and meeting the requirements of seismic performance of special moment frames.