• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.138-145
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• 2017

The purpose of this study is to establish a reasonable analytical method for the estimation of overall behavior characteristic from cracking to yielding of rebar and crushing of concrete and seismic performance of reinforced concrete shear wall with high-strength reinforcing bar. A total of 8 specimens of reinforced concrete walls which have constant aspect ratio and a variety of variables such as reinforcement ratio, reinforcement yielding strength, reinforcement details, concrete design strength, section shape and whether lateral restraint hoop were selected and the analysis was performed by using a non-linear finite element analysis program (RCAHEST) applying the proposed constitutive equation by the authors. The mean and coefficient of variation for maximum load from the experiment and analysis results was predicted 1.04 and 8%. The mean and coefficient of variation for displacement corresponding maximum load from the experiment and analysis results was predicted 1.17 and 19% respectively. The analytical results were predicted relatively well the fracture mode and the overall behavior until fracture for all specimens. These results are expected to be used as basic data for application of high-strength reinforcing bar to design codes in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.201-208
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• 2003

The Hybrid Wall System(HWS) building composed of center core reinforced concrete walls and exterior steel frame has open space around the center core walls. It is necessary to develop design methodologies for the HWS building that the coupled shear walls withstand the most of lateral load and expect the most energy dissipation at the coupling beams and at wall foots. Major factors considered in this paper are connection type of coupling beams and scale of story. The studies of the system are investigated in terms of shear force, overturning moment, maximum lateral displacement, story drift ratio, and dynamical characteristics under the action of vertical and lateral forces such as wind and seismic loads.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.2
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• pp.15-26
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• 2010

The purpose of this study is to develop a precast concrete structural wall system that can assure reliable seismic performance. In previous studies, the connections of precast concrete structural walls have had some problems in their seismic performance. Therefore, this research proposes precast concrete structural walls which have an improved seismic performance. One is a hybrid precast concrete structural wall that is composed of a reinforced concrete component and a precast concrete component, and another is a precast concrete wall whose reinforcements have a partially reduced section and are partially unbonded from the surrounding concrete. To evaluate the seismic performance of the proposed precast concrete structural walls, the behavior of three specimens, including a reinforced concrete wall, were subjected to reversed cyclic combined flexure and shear. According to the test results, the proposed precast concrete structural walls have reliable seismic performance.

• Journal of the Korean Society of Hazard Mitigation
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• v.2 no.4 s.7
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• pp.131-141
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• 2002

Precast concrete (PC) panels are often used as retaining walls to support soil pressure. In such a case, the panels should be connected at the location where PC panels meet with a buttress. However, it is not easy to provide enough development length for the reinforcing steels due to the limited width of the buttress. If it happens, the width of buttress should be increased as large enough although it is not desirable. The critical section required for providing the development length is always located where the flexural moment is maximum. Thus it is the place the buttress width ends. Also it is the place that the reinforcing steels stressed to maximum. However, it is possible to make differentiate between the maximum moment location and the most stressed location of reinforcing steels. It means that the most stressed location of reinforcing steels, the critical section, can be moved to the other place where the moment is not maximum. New critical location will have less moment than that of buttress width ends. In consequence, the development length would be longer than that of the typical way of construction. Debonding or cutting technique make it possible to reduce the moment strength of a section. Therefore reinforcing steels are debonded or cut to have a desired flexural strength at a desired place. In this study, five test specimens in full scale were erected to examine the effects of critical section movement in PC panel joints. Test parameters were the length variations of debonded and cut reinforcing steels. The test results showed that the debonding or cutting technique could be used to lengthen the development length in the joint of PC panels.

• Journal of the Korea Institute of Building Construction
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• v.24 no.4
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• pp.447-458
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• 2024

This study investigates the effectiveness of Building Information Modeling(BIM) software, specifically SketchUp and Revit, in reducing errors during quantity take-off(QTO) for complex building elements. While 3D modeling offers advantages, existing software may not fully account for manufacturing discrepancies, such as variations in concrete cover thickness and reinforcing bar radius. To address this limitation, this research proposes a BIM-based QTO method for high-insulation wall panels with intricate details. The method utilizes a BIM family library, focusing on key parameters like concrete cover thickness and inner radius of shear reinforcement. A case study compared the cross-sectional details of a wall panel modeled in Revit with the actual manufactured specimen. The analysis revealed a 12% reduction in modeled concrete cover thickness and a 1.27 times larger modeled inner radius of the shear bar compared to the real-world values. The proposed method incorporates these manufacturing variations into the Revit model of the high-insulation wall panel. Software like Navisworks facilitates the identification and correction of any material interferences arising from these adjustments. Furthermore, the method employs a unit wall concept(1m²) to account for the volume of various materials, including insulation and splice sleeves at joints. This allows for the identification of a similar existing family within the BIM library(e.g., "Double RC wall with embedded insulation") that reflects the actual material quantities used in the wall panel. By incorporating these manufacturing-induced variations, the proposed method offers a more accurate QTO process for complex high-insulation wall panels. The "Double RC wall with embedded insulation" family within the Revit program serves as a valuable tool for material quantity estimation in such scenarios.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.40-47
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• 2022

The present study aimed to examine the effectiveness of different techniques for controlling the diagonal cracks at the corners of openings on the strength, deformation, and crack propagation in reinforced concrete walls. The crack control strip proposed in this study, the conventional diagonal steel reinforcing bars, and stress-dispersion curved plates were investigated for controlling the diagonal cracks at the opening corners. An additional crack self-healing function was also considered for the crack control strip. To evaluate the volume change ratio and crack width propagation around the opening, downsized wall specimens with a opening were tested under the diagonal shear force at the opening corner. Test result showed that the proposed crack control strip was more effective in reducing the volume change and controlling the crack width around the opening when compared to the conventional previous methods. The crack control strip with crack healing feature displayed the superior performance in improving the strength of the wall and reducing the crack width while healing cracks occurred in the previous tests.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.1
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• pp.63-70
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• 2010

The purpose of this study is to investigate experimentally the behavior of unreinforced masonry RC frames strengthened by CFRP sheet under cyclic lateral loading. Four test specimens were constructed as one-story, one-bay, 1/2 scale unreinforced masonry infilled RC frames and differences in strength and stiffness were evaluated in specimens on which had been applied different retrofitting methods. Test results indicated that the CFRP sheets significantly increased the strength and stiffness of the specimens, and the specimens retrofitted in columns and masonry indicated the most adequate retrofitting methods.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.2 s.54
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• pp.95-104
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• 2007

Three types of high-rise RC building structures having irregularity in the lower two stories were selected as prototypes and were performed nonlinear static analysis by using OpenSees to verify the analysis technique and to investigate the seismic capacity of those buildings. The first one has a symmetrical moment resisting frame (Model 1), the second has an infilled shear wall in the central frame (Model 2), and the third has an infilled shear wall only in one of exterior frames (Model 3). Fiber model, which consists of concrete and reinforcing bar represented from stress-strain relationship, is adapted used for simulate the nonlinearity of members, and MVLEM(Multi vertical linear element model) is used for simulate the behavior of wall. The analytical results are simulate the behavior of piloti stories well, for example, the stiffness and yield farce of piloti stories, the up-lift of wall and the variation of lateral stiffness of column due to the variation of axial forces. Overstrength of Model 2 and Model 3 are about 2 times larger than that of Model 1. The reason of the high oversttrength and ductility of Model 2 and Model 3 is that the conservative design of Model 2 and Model 3, whose beam and column sections are the same as those of Model 1. The ductilities of Model 1 and Model 3 are slightly larger than that of Model 1 and Model 3. Model 1 and Model 3 reached mechanism condition, whereas Model 2 failed to the shear failure of shear wall and the large axial forces in columns due to large overturning moment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.114-120
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• 2017

In this paper, the effect of the masonry infill walls on the seismic performance of the reinforced concrete(RC) frames with non-seismic details was evaluated through the static test of an masonry infilled RC frame sub-assemblage with non-seismic details of real size, and comparison with the test results of the RC frame sub-assemblage with non-seismic details. As the test results, lots of cracks occurred on the surface of the entire frame due to the compression of the masonry infilled wall, and the beam-column joint finally collapsed with the expansion of the shear crack and buckling(exposure) of the reinforcement. On the other hand, the stiffness of the shear force-story drift relationship decreased due to the wall sliding crack and column flexural cracks, and the strength finally decreased by around 60% of the maximum strength. The damage that concentrated on the upper and lower parts of columns was dispersed in the entire frame such as columns, a beam, and beam-column joints due to the wall, and the specimen was finally collapsed by expansion of the shear crack of the joint, not the shear crack of the column. Also, the stiffness of RC frame increased by 12.42 times and the yield strength by 3.63 times, while the story drift at maximum strength decreased by 0.18 times.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.6
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• pp.293-299
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• 2018

Steel truss outriggers can be replaced by reinforced concrete walls to control the lateral drift of tall buildings. When reinforced concrete outrigger walls are connected to perimeter columns, not only axial forces but also shear forces and moments can be induced on the perimeter columns. In this study, the shear force of the perimeter column due to the rotation of the outer edge of the outrigger wall is derived as analytic equations and the result is compared with the finite element analysis result. In the finite element analysis, the effects of connecting beams at each floor and the effect of modeling shear walls and outriggers with beam element and plane stress element was analyzed. The effect of the connecting beam was almost negligible and the plane stress element was determined to have greater stiffness than the beam element. The inter-story rotation and the shear force of the perimeter column due to the rotation of the outer edge of the outrigger wall was considerably smaller than the allowable value. Therefore, even if the outrigger wall made of reinforced concrete is applied to a tall building, it is considered that there is no need to study the shear force and moment induced in the perimeter columns.