• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.6
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• pp.283-291
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• 2018

This study intends to develop an analytical model of unreinforced masonry(URM) walls for the nonlinear static analysis which has been generally used to evaluate the seismic performance of a building employing URM walls as seismic force-resisting members. The developed model consists of fiber elements used to capture the flexural behavior of an URM wall and a shear spring element implemented to predict its shear response. This paper first explains the configuration of the proposed model and describes how to determine the modeling parameters of fiber and shear spring elements based on the stress-strain curves obtained from existing experimental results of masonry prisms. The proposed model is then verified throughout the comparison of its nonlinear static analysis results with the experimental results of URM walls carried out by other researchers. The proposed model well captures the maximum strength, the initial stiffness, and their resulting load - displacement curves of the URM walls with reasonable resolution. Also, it is demonstrated that the analysis model is capable of predicting the failure modes of the URM walls.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.75-85
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• 2023

In areas where excavation works are carried out, it is very important to select a retaining wall method to minimize ground water level and ground subsidence changes. In this regard, the use of Secant Pile Wall(SPW) method, which can complement the disadvantages of the CIP method, is gradually domestic increasing for the construction of retaining wall method. This study investigated the design elements of the SPW method and the interrelationship between the structural stability factors of the wall. The design elements for the retaining method are the overlap length between piles, pile diameter, and the specifications of the H-Beam specifications, while the structural stability factors of the wall are the bending stress, shear stress, horizontal displacement, and concrete strength. The study results showed that the pile diameter and H-Beam specifications have a significant impact on the capacity of the H-Beam, the overlap length and pile diameter have a significant impact on the horizontal displacement, and the pile diameter and H-Beam specifications have a significant impact on the required strength of the concrete.

• Journal of the Korean Geotechnical Society
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• v.24 no.10
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• pp.71-81
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• 2008

Wall displacements caused by earth pressure, rainfalls, rise in ground water level, inappropriate deep excavation and structural defects of the wall may produce differential settlements to existing buildings, which often result in damages and/or collapses of the building structures. In this case, measures to protect the walls and nearby structures would be required. One of the recent measures to reduce differential settlements and protecting walls is to reinforce the ground using micro-piles. In this study physical model tests were carried out to evaluate the performance of the micro-pile method. It is revealed that reduction of the settlement was maximized when the length of micro-pile is twice of the foundation width, distance between piles is twice of the pile diameter and the distance to wall is one tenth of the foundation width. Based on the test results some design recommendations were made.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.43-50
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• 2000

This paper presents the measured performance of in-situ walls using the measured data collected from various deep excavation sites in urban area. A variety of in-situ wall systems from 57 sites were considered, including H-pile walls, soil cement walls, cast-in-place pile walls, and diaphram walls. The examination included lateral wall movements as well as apparent earth pressure distributions. The measured data were thoroughly analyzed to investigate the effects of various components of in-situ wall system, such as types of wall and supporting system, on the lateral wall movement as well as on the apparent earth pressure distribution. The results wee then compared with the current design/analysis methods, and information is presented in chart formes to provide tools that can be used for design and analysis. Using the measured data, a semi-empirical equation for predicting deep excavation induced maximum lateral wall movement is suggested.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.434-437
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• 2004

본 반층벽체 적용지역의 경우, 침출수의 영향으로 암모니아성 질소의 농도가 최대 29.12mg/L까지 검출되고 있으며 반응물질은 암모니아성 질소제거에 적합한 제올라이트를 선정하였다. 투수성 및 다짐강도를 고려하여 왕사와 50:50의 비율로 혼합, 적용하였으며 지하수 평균유속은 0.0864m/d이고 평균지하수위는 원지반 기준 - 4.0m의 분포를 나타내었다. 지질조사 결과, 적용구간의 지질구조는 매립층, 풍화토, 풍차암, 연암의 순서로 분포하고 있으며, 반응벽체의 설계깊이는 현장 시추조사 결과를 바탕으로 지하수의 Under-pass를 방지하기 위하여 연암층 50cm까지 관입시키도록 설계하였다. 최종적으로 선정된 반응벽체의 규모는 35m(길이) $\times$ 1.2m(두께) $\times$ 8.5 ～ 9.42m(구간별 깊이)로 설계에 반영되었다. 현재, 지하수감시정을 이용한 모니터링 결과, 상부지하수 감시정에서의 오염원은 우기의 영향으로 간헐적으로 발생하고 있으나 하부 지하수 감시정에서의 암모니아성 질소농도는 불검출 되거나 0.5 mg/L 이하로 유지되고 있다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.1
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• pp.45-55
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• 2022

Because boundary confinement details proposed in the current design standards are significantly inferior in workability and production quality, it is necessary to develop boundary confinement details of RC structural walls that are capable of ensuring seismic performance and workability. With the recent development of the wire rod manufacturing technology, various pre-fabricated continuous hoop details can be manufactured. In this study, an analysis was conducted on the moment-curvature relationship of RC structural walls to which the pre-fabricated continuous hoop details were applied. According to the nonlinear cross-section analysis, the RC structure wall to which the details of the pre-fabricated continuous hoop details are applied can ensure seismic performance as the area of the pre-fabricated continuous hoop increases. Based on these research results, when applying the pre-fabricated continuous hoop in detail, it is necessary to secure the area of the pre-fabricated continuous hoop as much as the area of the existing boundary confinement.

• Journal of Korean Society of Steel Construction
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• v.16 no.4 s.71
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• pp.397-406
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• 2004

This paper presents the test and evaluation results on the shear strength and stiffness of a light steel stud wall from a lightweight foamed mortar (lightweight hybrid wall). The use of a lightweight foamed mortar was aimed at improving structural performance, thermal performance, and finish. Studiesshowed that it did not affect thermal performance, but it contributed to structural performance and finish when the unit weight was more than 0.8 (Editor's note: Please indicate the unit of measurement.). In this study, 14 specimens-whose parameters included the specific gravity of the lightweight foamed mortar (0.6, 0.8, 1.0, 1.2), the spacing of the stud (450 mm, 600 mm, or 900 mm), finishing materials (such as lightweight foamed mortar, OSB, and gypsum board), and bracing-were manufactured. Three typical, steel house-framing specimens were added to compare the test results with the 14 specimens. The results of in-plane shear tests show that the use of lightweight foamed mortar (1.15~5.38 times stronger, 1.45~13.7 times stiffer) results in ultimate strength and initial stiffness. In addition, it was possible to widen the stud spacing to up to 900 mm without decreasing shear strength. It was very important to prevent the lightweight foamed mortar from shrinking and to secure the adhesion between the steel stud and the lightweight foamed mortar to improve structural performance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.1-9
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• 2022

In this study, the in-plane and out-of-plane seismic performance of the masonry wall strengthened using the steel bar truss system proposed by Hwang et al. (2021a, 2021b) or using FRP sheets were compared and evaluated. The maximum strength of the masonry wall reinforced with FRP sheets for the in-plane and out-of-plane loading was 71% and 85%, respectively, of that of the non-reinforced masonry wall. Meanwhile, the maximum strength of the masonry wall reinforced with the steel bar truss system was approximately 1.8 times higher than that of the non-reinforced masonry wall. Compared with the FRP sheet method, the steel bar truss system was excellent at improving the maximum load capacity, rigidity, and energy dissipation capacity. However, in the case of a masonry wall reinforced with FRP sheets, the masonry wall was overstrengthened with the FRP sheets covering the entire masonry wall, and it is considered that the overstrengthened specimen experienced sliding failure, resulting in a lower strength than the other specimens. A follow-up study is needed to compare the seismic performance of the specimen involving only a part of the masonry wall reinforced with the FRP sheets and the specimen reinforced using the steel bar truss system.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.1
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• pp.43-53
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• 2002

Current torsional provisions focus n restricting torsional effect of asymmetric wall structures by proportioning strength of wall based on the traditional assumption that stiffness and strength are independent. Recent studies have pointed out that stiffness of structural wall is dependent on the strength. This implies that actual stiffness of walls can be determined only after torsional design is finished and current torsional provisions may result in significant errors. To overcome this shortcoming, this paper proposes deformation based torsional design for asymmetric wall structures. Contrary to the current torsional provisions, deformation-based torsional design uses displacement and rotation angle as design parameters and calculates base shear for inelastic torsional response directly. Main purpose of deformation based torsional design is not to restrict torsional response but to ensure intended torsional mechanism according to the capacity design concept. Because displacement and rotation angle can be used as performance criteria indicating performance level of asymmetric structures, this method can be applied to the performance based seismic design effectively.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1001-1009
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• 2005

The usefulness of walls in the structural planning of multistory buildings has long been recognized. When walls are situated in advantageous positions in a buildings, they can be very efficient in resisting lateral load. Specially coupled shear wall system is the primary lateral load resisting system of buildings. It is customary to refer to such walls as being 'coupled' by coupling beams. The coupling beams must exhibit excellent strength, stiffness ductility and energy dissipation capacity. To achieve these demands for steel coupling beam, steel coupling beam with Face Bearing Plate(FBP) embedded in the reinforced concrete walls is proposed. A comprehensive experimental test involving 2 steel coupling beam with and without FBP has been performed. Through experimental study, the evaluation of the advantage of that was establish and proposed the failure mode.