• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.168-169
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• 2015

SMART Frame is a composite precast concrete structure system to deliver the advantages of both steel frame and reinforced concrete. Many studies have established to date that SMART Frame is more advantageous than conventional frame-type structure in terms of structural stability, constructability, economic viability as well as reduction of construction schedule. However, such studies have focused primarily on wall-type or flat slab-type apartment housing structures, failing to include Rahmen structures in their scope. Accordingly, this study aims to analyze the benefits of potential application of SMART Frame to RC Rahmen structures. As the structural stability and constructability of SMART Frame is already proven, this study reviews its benefits from the perspective of cost reduction. Conclusion of this study will be used subsequently in predicting the benefits of SMART Frame when it is adapted to RC Rahmen structures.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.14-15
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• 2013

Green Frame is precast concrete column-beam structure. There are three types on column connection. The coupler type which is one of the three, need to be improved because of unstability caused by pre-installation of column before casting the slab, and quality deterioration caused by lack of workspace. Therefore, in this study, new coupler connection type with thread rebar is suggested. The result of this study shall be used for the efficiency analysis of the new coupler connection.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.156-165
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• 2011

This study investigates the horizontal shear behavior of an interface between precast concrete (PC) and topping concrete(RC), and evaluates the horizontal based on the investigations by the experimental. Horizontal shear strength in connected surface is determined by the roughness an interface and the shear reinforcement or not. In this study, the main experimental parameters are the shear reinforcement types in the shape of loop-type and lattice-type, rebar spacing. A total of four specimens were shear strength tested and manufactured. As a result, the horizontal shear strength of reinforced connected surface was found to be controlled by deformation in vertical direction. Comparison of reinforcement shape, the mean initial crack load loop type specimens, the average maximum load and the junction of the average in terms of initial stiffness, respectively 33.7%, 45.9% and 55.2% were large enough. Evaluation results for shear strength equation of existing standard domestic, the loop-type reinforced 2.32 to 4.23 times, lattice-type reinforced 1.65 to 3.06 times appears to be higher. Behavior of interface or strength of structural design criteria was fairly safe side. It does not have any problems in the applied field is considered.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.89-100
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• 2022

The development of the Construction Production Rates System for appropriate construction cost calculation has recently come to the fore as a means of invigorating OSC based PC structure which currently needs institutional frameworks. PC structure based construction expenses consist of the factory-built assembly, transportation and on-site installation. Recently, in the field of transportation and site installation, research on product structure development is being conducted, such as presenting the standard product calculation system reflecting the results of field survey for each subsidiary materials (Lee et al., 2021). On the other hand, there is no ongoing research on estimating construction expenses of Factory-built assembly. This study suggests Construction Production Rates System which can be used for PC subsidiary materials based Factory-built assembly cost estimations. For the research, work types for the construction procedures have been categorized, and the standard input manpower suitable for the corresponding work characteristics has been derived from analyzing the associated Construction Standard Production Rates for each work type. Also, as the research referred PC subsidiary materials (such as columns, beams, walls, and slab, as well as on-site installation) and the standard number of workforce based on work types, one can calculate direct labor cost, using what the research shows. In addition, it suggests that the size of individual subsidiary materials be the extra cost factor, by using the characteristics that productivity changes depending on the size(m³) of subsidiary materials. It is expected that the research can contribute to objectively verifying factory-built assembly cost through of PC structure, which currently relies on estimates.

• Journal of the Korea Institute of Building Construction
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• v.16 no.5
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• pp.429-436
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• 2016

Because of the shortage of construction workers due to The rising labor costs and an aging labor force, construction time has been extended. As a solution, The construction time of high-rise buildings can be reduced by adopting precast concrete construction methods. Most relevant studies have focused on the development and structural analysis of such methods and not on their construction management. Therefore, this study focused on the construction management of the hollow precast concrete column (HPC) method. The objective of this study was to evaluate the performance of HPC formulations through the analytic hierarchy process and benefit-cost analysis. After a gap analysis of the available literature and expert interviews, the evaluation criteria were selected. A questionnaire survey was administered to professionals with ample experience in precast concrete construction for the pair-wise evaluation of the benefit and costs of the HPC method. The results show that the benefits of the HPC method outweighed its costs. Therefore, the HPC method is a suitable substitute for the half-slab method.

• Journal of the Optical Society of Korea
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• v.17 no.3
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• pp.262-268
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• 2013

We study the focusing properties of a two-dimensional square-lattice photonic crystal (PC) comprising silica and germanium partitioned cylinders in air background. The finite difference time domain (FDTD) method with periodic boundary condition is utilized to calculate the dispersion band diagram and the FDTD method incorporating the perfectly matched layer boundary condition is employed to simulate the image formation. In contrast to the common square PCs in which the negative refraction effect occurs in the first photonic band without negative phase propagation, in our suggested model system, the frequency with negative refraction exists in the second band and in near-infrared region. In this case, the wave propagates with a negative phase velocity and the evanescent waves can be supported. We also discuss the dependency of the image resolution and its location on surface termination, source location, and slab thickness. According to the simulation results, spatial resolution of the proposed PC lens is below the radiation wavelength.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.3-12
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• 2020

Nowadays, as-is BIM generation has been popularly adopted in the architecture, engineering, construction and facility management (AEC/FM) industries. In order to generate a 3D as-is BIM of a structural component, current methods require a registration process that merges different sets of point cloud data obtained from multiple locations, which is time-consuming and registration error-prone. To tackle this limitation, this study proposes a registration-free 3D point cloud data acquisition technique for as-is BIM generation. In this study, small-size mirrors that rotate in both horizontal and vertical direction are used to enable the registration-free data acquisition technique. First, a geometric model that defines the relationship among the mirrors, the laser scanner and the target component is developed. Second, determinations of optimal laser scanner location and mirror location are performed based on the developed geometrical model. To validate the proposed registration-free as-is BIM generation technique, simulation tests are conducted on key construction components including a PC slab and a structural wall. The result demonstrates that the registration-free point cloud data acquisition technique can be applicable in various construction elements including PC elements and structural components for as-is BIM generation.

• Journal of Korean Society of Steel Construction
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• v.20 no.4
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• pp.493-504
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• 2008

This paper deals with the experimental analysis of the flexural behaviour of encased composite beams with hollow core slabs and channels. The shear force between steel beams and hollow core slabs are transferred by channels. Three full-scale specimens were constructed and tested with different steel beam heights, which were compared with those of previous studies. Based on observation of the experiments, the encased composite beams exhibited full shear connection behaviour without any other shear connectors due to their inherent mechanical and chemical bond stress. Experimental results show a behaviour similar to steel-concrete composite beams with classical connectors: elastic and yield domains, great ductility, flexural failure mode (plastic hinge), low relative movement at steel-concrete interface and all specimens failed in a very ductile manner. Consequently, this study enables the validation of the proposed connection device under static loading and shows that it meets modern structural requirements.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.108-115
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• 1990

This paper contains experimental studies on the flexural cracking behabior of PPC one-way slabs. Three post tensioned bonded PPC slabs with the same prestressing ratio and ultimate moment strength were tested. Based upon test results, this paper also presents the crack width prediction formula PPC slab. According to the crack theory developed mainly in Europe, crack width formula is given as the product of crack spacing and mean steel strain after decompression. Aaaaverage crack spacing formula is composed of many factors mainly such as concrete cover, concrete effective area in tension, sum of reinforcing bars perimeters and mixed reinforcements. In particular, it is very important to specify the bond characteristics of mixed reinforcements, since bond characteristics of PC bars are different from those of non-tensioned deformed bars. For this reason, a reduced bond coefficients for PS bars is employed in this study.

• Journal of Korean Association for Spatial Structures
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• v.15 no.3
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• pp.95-102
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• 2015

Numerical model on precast prestressed concrete (PC) hollowcore slabs using 11.3 mm diameter 7-wire stand was developed based on finite element analysis. In order to validate the modelling, previous experiment results with respect to prestressed solid concrete slabs were used and compared throughout the course of fire exposure. In addition to, the fire performance of hollowcore slabs with different aggregate types, moisture contents and compressive strength of concrete was investigated. As a result, it can be seen that the type of aggregates and moisture contents used in hollowcore slabs can affect the fire performance as well as temperature developments.