• Structural Engineering and Mechanics
• /
• 제59권4호
• /
• pp.653-669
• /
• 2016

Recent earthquakes worldwide show that a significant portion of the earthquake shaking happens in the vertical direction. This phenomenon has raised significant interests to consider the vertical ground motion during the seismic design and assessment of the structures. Strong vertical ground motions can alter the axial forces in the columns, which might affect the shear capacity of reinforced concrete (RC) members. This is particularly important for non-ductile RC frames, which are very vulnerable to earthquake-induced collapse. This paper presents the detailed nonlinear dynamic analysis to quantify the collapse risk of non-ductile RC frame structures with varying heights. An array of non-ductile RC frame architype buildings located in Los Angeles, California were designed according to the 1967 uniform building code. The seismic responses of the architype buildings subjected to concurrent horizontal and vertical ground motions were analyzed. A comprehensive array of ground motions was selected from the PEER NGA-WEST2 and Iran Strong Motions Network database. Detailed nonlinear dynamic analyses were performed to quantify the collapse fragility curves and collapse margin ratios (CMRs) of the architype buildings. The results show that the vertical ground motions have significant impact on both the local and global responses of non-ductile RC moment frames. Hence, it is crucial to include the combined vertical and horizontal shaking during the seismic design and assessment of non-ductile RC moment frames.

• 한국안전학회지
• /
• 제38권3호
• /
• pp.61-68
• /
• 2023

This study performed a structural performance evaluation of a system scaffolding for elevator installation work developed in previous studies. The structural performance was evaluated via a structural test conducted to apply the working load specified in the design standard. The deflection of the horizontal member and the stress of each member constituting the system scaffolding were measured. Consequently, the structural safety evaluation including structural behavior and required performance was performed using the deflection and stresses measured from the structural test. The structural test and safety evaluation results based on the heavy working load corresponding to the design load indicated that the deflection, which is the performance criterion of the horizontal member, did not exceed the allowable value. Further, each member's stress, which is a safety evaluation indicator, did not exceed the allowable strength for both horizontal and vertical members with bending behavior and fordable bracing with tensile behavior, while also satisfying the required safety factor. In addition, the results confirmed the safety against deformation, partial damage, and destruction owing to excessive and maximum load. Therefore, the system scaffolding developed in this study satisfies both the structural performance and safety required by the design standards; thus, it can be applied to elevator installation work sites.

• Computers and Concrete
• /
• 제32권5호
• /
• pp.527-541
• /
• 2023

This paper emphasizes the use of CFT columns in frame structures subjected to strong horizontal forces and shows that the efficiency of using CFT columns is increased when the plastic design approach is adopted. Because the plastic design approach is based on redistribution of the force of the internal member, a double node for the rotational degrees of freedom, where the adjacent two rotational degrees of freedom can be connected by a non-dimensional spring element, is designed and implemented into the formulation. In addition, an accompanying criterion is considered in order to make it possible to describe the continuous moment redistribution in members connected to a nodal point up to a complete plastic state. The efficiency of CFT columns is reviewed in comparison with RC columns in terms of the cost and the resistance capacity, as defined by a P-M interaction diagram. Three representative frame structures are considered and the obtained results show that the most efficient and economical design can be expected when the use of CFT columns is considered on the basis of the plastic design, especially when a frame structure is subjected to significant horizontal forces, as in a high-rise building.

• 전기의세계
• /
• 제17권3호
• /
• pp.43-56
• /
• 1968

The design of this antenna tower on the publication had been prepared by writer in order to compare with that of towers for power transmission line or to show the differences on designs existing on their design standards. The design of this antenna tower is also featuring on the following points; (1) the height of tower is 150meters high, (2) combined steel angles are adopted besides angles, (3) the direction of 45degree wind is taken account into design, (4) the additional stresses of horizontal members located in the bending points of main posts are contemplated though these additional stressess are not shown on stress diagram.

• 한국공간구조학회논문집
• /
• 제23권2호
• /
• pp.19-28
• /
• 2023

Timber structures are susceptible to moisture, contamination, and pest infestation, which can compromise their integrity and pose a significant fire hazard. Despite these drawbacks, timber's lightweight properties, eco-friendliness, and alignment with current architectural trends emphasizing sustainability make it an attractive option for construction. Moreover, timber structures offer economic benefits and provide a natural aesthetic that regulates building temperature and humidity. In recent years, timber domes have gained popularity due to their high recyclability, lightness, and improved fire resistance. Researchers are exploring hybrid timber and steel domes to enhance stability and rigidity. However, shallow dome structures still face challenges related to structural instability. This study investigates stability problems associated with timber domes, the behavior of timber and steel hybrid domes, and the impact of timber member positioning on dome stability and critical load levels. The paper analyzes unstable buckling in single-layer lattice domes using an incremental analysis method. The critical buckling load of the domes is examined based on the arrangement of timber members in the inclined and horizontal directions. The analysis shows that nodal snapping is observed in the case of a concentrated load, whereas snap-back is also observed in the case of a uniform load. Furthermore, the use of inclined timber and horizontal steel members in the lattice dome design provides adequate stability.

• 한국지반환경공학회 논문집
• /
• 제20권1호
• /
• pp.43-49
• /
• 2019

본 논문에서는 쏘일네일 설계에 위상최적화 기법을 도입하여 비탈면 높이별로 필요로 하는 보강력을 최적화하였다. 최대 비탈면 높이에서의 최적설계 결과를 보강형상밀도화하여 비탈면의 높이 변화에 따라 적용 시 쏘일네일의 수평간격의 위상최적화가 가능하였다. 단계별로 비탈면 높이를 달리하여 한계평형해석을 수행하고 쏘일네일의 수평간격이 고정값일 때 초과되는 안전율을 확인하였다. 비탈면 높이에 따른 필요 보강력을 밀도화 함으로써 최적화의 과정을 효율적으로 수행할 수 있었다. 또한 쏘일네일의 축력을 보강형상밀도에 반영하기 위하여 유한요소법을 이용하여 부재력을 반영하였다. 보강형상밀도를 산정하여 비탈면 높이별로 위상최적기법을 적용 시 비탈면 높이마다 기준안전율을 만족하는 반복적인 재해석과정을 효과적으로 감소시킬 수 있어 수평간격을 위상 최적화하는 방법이 경제적인 설계에 활용도가 높을 것으로 판단된다.

• 건축역사연구
• /
• 제17권4호
• /
• pp.97-112
• /
• 2008

In this study, I attempted to the architectural design characteristics of Daeung-Jeon in Sudeok Temple. For this purpose, After I set up several assumptions in the basis of the general characteristics of Korean wood architecture, and then, analyzed floor plan, structural formation and section sizes of structure and bracket members in relation to module and unit. As the results, the characteristics of the design process of plan and structure are follows. (1) 1 ja(尺), the unit applied to this building is measured $307.6{\sim}318.3mm$) and the average is 312.9mm (2) It is estimated that the floor plan designed on the basis of the top of columns. By the applied unit, every bay of the front side and the side is each designed by 15 ja and 8.5 ja. (3) The section is composed of piled members which have same section size. As basic module of section size called 'jae(재;材)', it is estimated at width 0.45 ja by height 0.75 ja. And as the secondary module, height between jae and is called 'gyoe(계;)' and it wes designed by three height size of 0.25 ja, 0.27 ja and 0.30 ja, (4) It is estimated that the section plan was designed by the order as follows. Firstly, the horizontal position of purlins wes decided on the basis of the intersection point of long and short rafters, and then the position and the section size of purlins and jangheyo(長舌) wes decided on the basis of the slope of roof and rafters. Secondly, going down from purlins, the members of structure composed of 'jae' and 'gyoe' was repeated. Lastly, for the purpose of linking the structure members located on the center line of adjacent purlins organically, the height of whaban(화반) was controlled.

• 벤처창업연구
• /
• 제17권3호
• /
• pp.201-214
• /
• 2022

본 연구에서는 조직 내 구성원들이 인식하는 조직학습문화가 과업성과와 맥락성과에 미치는 영향을 조직 커뮤니케이션이 매개하는지를 이론 및 실증적으로 검토하였다. 조직학습문화는 지식을 창출하고 습득하고 이전하며 새로운 지식과 통찰력을 반영하기 위해 행동을 수정하는데 능숙한 문화로 정의된다. 본 연구에서는 조직학습문화 인식이 조직 내 구성원 간의 커뮤니케이션을 통해 성과를 높일 수 있다는 가설을 선행연구를 통해 도출하였다. 특히 조직 내 커뮤니케이션을 상향, 수평, 하향의 3가지 유형으로 나누어, 상사나 동료, 부하와의 소통이 각각 매개하는지 살펴보았다. 실증연구에서 독립변수는 조직학습문화 인식, 매개변수는 상향, 수평, 하향 커뮤니케이션, 종속변수로는 종업원의 성과인 과업성과와 맥락성과를 설정하였다. 가설1은 조직학습문화와 종업원의 과업 및 맥락성과의 관계, 가설2는 가설1의 관계에 대해 커뮤니케이션이 가지는 매개효과로 설정하였다. 실증연구에서는 연구변수의 타당성과 신뢰도를 검증한 후, 상관관계 분석, 가설검증을 실시하였다. 가설1은 회귀분석을 통해 검증한 결과, 세부가설이 모두 지지되었다. 가설2를 검증하기 위해 process macro를 이용한 붓스트랩 검정을 실시하여 총 효과, 직접효과, 간접효과를 분리하고 간접효과의 유의성을 살펴보았다. 결과, 가설2는 일부 지지되었는데, 하향 커뮤니케이션이 조직학습문화와 과업·맥락성과를 매개하였으며, 수평 커뮤니케이션이 조직학습문화와 맥락성과를 매개하였다. 상향 커뮤니케이션의 매개효과는 유의하지 않게 나타났다. 본 연구 결과를 통해 시사점을 도출하고 연구의 한계점, 향후 연구 방향을 제시하였다. 조직학습문화는 구성원들의 학습과 성장을 통해 목표를 달성하려는 조직의 방향성이자 의도이다. 이러한 조직에 속한 구성원은 내면적 동기를 강화함으로 주어진 필수적 과업뿐 아니라 집단과 조직에 도움이 되는 자발적인 바람직한 행동을 하는 것으로 볼 수 있다. 또한 이러한 관계는 하향 커뮤니케이션, 즉 부하에게 의견을 전달하고 업무지시와 피드백을 하는 리더들이 주도하는 커뮤니케이션을 매개로 나타남으로 리더십 교육을 통하여 조직학습문화와 성과 간의 관계를 강화하기 위한 노력을 기울여야 할 것이다.

• 경영과학
• /
• 제12권2호
• /
• pp.1-14
• /
• 1995

Recently Korean textile industry has been in the phase that requires its strategy change from the less-develped country style of the labor-intensive products to the developed country style of the technology-intensive products. It needs to make more efforts to develop the value-added products to meet the customer's various needs. In addition, development of technology, equipment, and design is required to implement its corporate strategy successfully. Although Korean textile companies have currently kept skillful labor and advanced equipments, they are losing their share in the international textile markets. This is mainly because corporate management has not been involved with efficient strategy. Strategy is an adoption of a company to environment by its corporate members, thus leading to the requirement of coordination of the main functions such as manufacturing and marketing. In fact, the coordination of the two departments toward reaching the corporate goal is not easy since the two are interested in different areas, respectively. Manufacturing people show their interests in production capacity, equipment layout, process technology, quality, purchasing, and labor while marketing people, target customer, product mix, advertisement, product specification, and customer service. For this reason, conflicts sometimes happen between the two departments. There are, however, many area that need a horizontal cooperation, for instance, in layout, process technology, product mix, and potential demand. Therefore, reciprocal coordination is necessary for achieving the firm's common objectives. This study was concerned with determining the factors that enhance the competitiveness of textile firms so that they could reach the common goal of the two departments with a horizontal collaboration.

• Earthquakes and Structures
• /
• 제19권4호
• /
• pp.261-272
• /
• 2020

Recent severe earthquakes in and around the vital public places worldwide indicate the severe vulnerability of ground excitation to be assailed. Reducing the effect of seismic lateral load in structural design is an important conception. Essentially, seismic isolation is required to shield the superstructure in such a way that the building superstructure would not move when the ground is shaking. This study explores the effectiveness, design, and practical feasibility of base isolation systems to reduce seismic demands on buildings of varying elevations. Thus, static and dynamic analyses were conducted based on site-specific bi-directional earthquakes for base-isolated as well as fixed-based buildings. Remarkably, it was discovered that isolators used in low-rise to high-rise structures tend to significantly decrease the structural responses of seismic prone buildings. The higher allowable horizontal displacement induces structural flexibility and ensure good structural health of the building stories. Reinforcement from vertical and horizontal members can be reduced in significant amounts for BI buildings. Thus, although incorporating base isolators increases the initial outlay, it considerably diminishes the total structural cost.