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

• International Journal of Highway Engineering
• /
• v.17 no.6
• /
• pp.37-45
• /
• 2015

PURPOSES : The purpose of this study is to validate the design criteria of the concrete modular road system, which is a new semi-bridge-type concept road, through a comparison of numerical analysis results and actual loading test results under static axial loads. METHODS : To design the semi-bridge-type modular road, both the bridge design code and the concrete structural design code were adopted. The standard truck load (KL-510) was applied as the major traffic vehicle for the design loading condition. The dimension of the modular slab was designed in consideration of self-weight, axial load, environmental load, and combined loads, with ultimate limit state coefficients. The ANSYS APDL (2010) program was used for case studies of center and edge loading, and the analysis results were compared with the actual mock-up test results. RESULTS : A full-scale mock-up test was successfully conducted. The maximum longitudinal steel strains were measured as about 35 and 83.5 micro-strain (within elastic range) at center and edge loading locations, respectively, under a 100 kN dual-wheel loading condition by accelerating pavement tester. CONCLUSIONS : Based on the results of the comparison between the numerical analysis and the full-scale test, the maximum converted stress range at the edge location is 32~51% of the required standard flexural strength under the two times over-weight loading condition. In the case of edge loading, the maximum converted stresses from the Westergaard equation, the ANSYS APDL analysis, and the mock-up test are 1.95, 1.7, and 2.3 times of that of the center loading case, respectively. The primary reason for this difference is related to the assumption of the boundary conditions of the vertical connection between the slab module and the crossbeam module. Even though more research is required to fully define the boundary conditions, the proposed design criteria for the concrete modular road finally seems to be reasonable.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.4
• /
• pp.539-548
• /
• 2008

This study aims to determine the applicability of the previously published T-type modular profile beam in the manner of producing specimens designed specially for the said purpose, determining their bending and shear behaviors depending on the presence of shear reinforcement, and analyzing the results in comparison with the theoretical equation of plastic deformation. The modular profile beam contributes to bending and shear resistance with the addition of the profile to the form function, and enhances the molding performance through the modular concept. The experimental results showed that the TS series specimens with shear reinforcement have bending behaviors superior to those of the T series specimens without shear reinforcement, which suggests that the used shear reinforcement appropriately bears the shear force. However, it was considered that all the specimens except for the T1-1 specimen failed to have adequate bending performance because of the intermodular slipping caused by the shear failure of the bolts. It is expected that further studies on the T-type modular profile beam, in which shear connectors will be considered as a variable,be performed to develop optimal intermodular connection methods.

• Steel and Composite Structures
• /
• v.27 no.5
• /
• pp.647-659
• /
• 2018

Through extensive research, there exist a new type of connection between railway bridge girders and steel-concrete composite panels. In addition to conventional shear connectors, newly developed blind bolts have been recently adopted for retrofitting. However, the body of knowledge on their influence and application to railway structures has not been thoroughly investigated. This study has thus placed a particular emphasis on the application of blind bolts on the Sydney Harbour Bridge as a feasible alternative constituent of railway track upgrading. Finite element modeling has been used to simulate the behaviours of the precast steel-concrete panels with common types of bolt connection using commercially available package, ABAQUS. The steel-concrete composite track slabs have been designed in accordance with Australian Standards AS5100. These precast steel-concrete panels are then numerically retrofitted by three types of most practical bold connections: head studded shear connector, Ajax blind bolt and Lindapter hollow bolt. The influences of bolt connections on load and stress transfers and structural behaviour of the composite track slabs are highlighted in this paper. The numerical results exhibit that all three bolts can distribute stresses effectively and can be installed on the bridge girder. However, it is also found that Lindapter hollow bolts are superior in minimising structural responses of the composite track slabs to train loading.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.6
• /
• pp.95-102
• /
• 2015

Recently, the maintenance activity for aging of bridge structures was difficult because of traffic jam, environment pollution and increasing cost. And to solve these problems, modular bridge research has been studied. After static and cyclic loading test was conducted for serviceability and bending performance with one way slab, effective moment of inertia of modular specimen was analyzed to estimate the deflection by KCI(2012). To conduct the test, one integral slab and three modular slabs were made for static loading and one integral and modular slab were made for cyclic. As a result of the test, the modular slab had the similar bending performance of the integral. But the ultimate deflection showed the insufficient which was smaller than 20%. In the cyclic loading test, the modular slab has different behavior of deflection with the integral, so it was evaluated difficult for serviceability. In addition, effective moment of inertia by KCI(2012) was not estimated for modular slab with connection. The new value of m which was ratio between moments is 4.53 based on result of test for predicting deflection of modular.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.28 no.1
• /
• pp.7-21
• /
• 2022

Purpose: As the pandemic period continues, various attempts are being made to new medical spaces in the medical society. Many hospitals, including existing general hospitals, have been effected by infected patients and are showing limitations in patient care capacity. Mobile-hospitals may be the starting point for the development of new environment in the medical society and healthcare facilities which are not replacing the role of existing hospitals. Mobile-hospitals can possibly respond to situations that require medical services and provide emergency care for various demands in connection with existing healthcare facilities. Methods: Through a total of five investigations/analysis, medical functions that can be inserted into mobile-hospitals based on modular architecture are set. The first is the analysis of domestic legal guidelines, the second is the analysis of previous studies, the analysis of emergency medical facilities and other medical spaces of hospitals to be compared, the fourth is the analysis of medical spaces of actual mobile hospital projects. Results: Through five analyses, medical functions applicable to the modular building platform were finally established. Mobile hospitals can be used not only in disaster sites such as infectious diseases, but also in medical underprivileged areas or general hospitals. Therefore, it is necessary to establish medical functions that meet the specificity of mobile hospitals along with the functions of existing fixed medical facilities. Furthermore, various studies such as use in international aid, use in normal times, and connection with other platform-based medical facilities are considered necessary. Implications: Through 5 strategies of analysis, 41 medical functions which can be applied to UNIT are decided and these functions will be placed where medical services will be required.

• Journal of the Korean Society of Safety
• /
• v.25 no.1
• /
• pp.57-61
• /
• 2010

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Scaffoling is a temporary frame used to support people and material in the construction or repair of buildings and other large structures. It is usually a modular system of metal pipes, although it can be made out of other materials. Bamboo is still used in some Asian countries like China. The purpose of a working scaffold is to provide a safe place of work with safe access suitable for the work being done. In construction site, steel pipes are usually used as scaffolds. In this study, scaffolding systems which is changed according to sleeper and joist space were measured by buckling test. Buckling load of respective scaffolding system was analyzed by structural analysis program(MIDAS). Buckling load of scaffold with/without wall connection and footboard was got by test and structural analysis. According to these results，we know that scaffolding system of case 3 is suitable. Buckling load of scaffold with wall connection is higher than without wall connection. So wall connection is important in scaffoling systems. Footboard in the scaffolding systems is not effective against promotion of buckling load. Finally, the present study results will be used to design scaffolding systems safely in the construction sites.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.8
• /
• pp.3626-3635
• /
• 2011

The modular robots are a kind of system that was developed to overcome the limitation of the movement for the mobile robot with wheels or legs. In legs type mobile robot case, they are limited for velocity and balance during moving at the uneven terrain. In wheeled mobile robot case, they are also limited to overcome dump, stair and so on. The modular robots can overcome moving limitation because of their transforming ability. However, they are researched not only driving mechanism but also combination mechanism. In this paper we proposed four kinds of unique structure for the combination and separation and also its algorithm. The effectiveness of the structure is verified with building the real structure and taking experiments to the designed modular robot

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2006.11a
• /
• pp.642-647
• /
• 2006

Recently Ministry of National Defense is reconstructing old facilities using modular construction method for enhancing soldiers' quality of living. In the future, the use of modular construction method is expected to be increased. But in beginning stage as ROK military facilities that was built by modular was not designed and constructed efficiently, problems for pilot projects need to be analyzed by phases and construction methods should be improved. For the maximized efficiency, design should be made to minimize on-site works, factory automation in an assembly plant should be installed for the better productivity, roads that will be used for transportation should be checked, and joint and connection methods between modules in on-site assembly should be improved for a better quality.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.2
• /
• pp.31-39
• /
• 2012

Recently new construction and reconstruction of the bridge have been required to minimize traffic congestion, environmental disadvantage, to reduce the period of construction, and to improve the quality and workability during the construction. For this reason, the application of modular bridge system, which is assembly of the structural members, is necessary to prepare for near future. Fall of girders can occur at the moment to connect between precast girders during the construction, so appropriate cross beams should be installed to solve the mentioned problem. In this study, understanding the structural characteristics and domestic and international case of cross beam, alternative cross beam system for modular bridge was developed. To inspect the structural characteristics of the alternative system, specimens were built and static loading test was performed. Afterward, the behavior of cross beam interms of joints and load distribution was observed. Experimental results were analyzed and compared with each data. Therefore, the appropriate cross beam system for modular bridge will be chosen and proposed in this paper.