• Geomechanics and Engineering
• /
• 제20권2호
• /
• pp.155-164
• /
• 2020

In recent years, the stability, safety and comfort of trains has received increased attention. The mechanical characteristics and differential settlement of the foundation are the main problems studied in high-speed railway research. The mechanical characteristics and differential settlement of the foundation are greatly affected by the ground treatment. Additionally, the effects of train load and earthquakes have a great impact. The dynamic action of the train will increase the vibration acceleration of the foundation and increase the cumulative deformation, and the earthquake action will affect the stability of the substructure. Earthquakes have an important practical significance for the dynamic analysis of the railway operation stage; therefore, considering the impact of earthquakes on the railway substructure stability has engineering significance. In this paper, finite element model of the CFG (Cement Fly-ash Gravel) pile + cement-soil compacted pile about composite foundation is established, and manual numerical incentive method is selected as the simulation principle. The mechanical characteristics and differential settlement of CFG pile + cement-soil compacted pile about composite foundation under train load are studied. The results show: under the train load, the neutral point of the side friction about CFG pile is located at nearly 7/8 of the pile length; the vertical dynamic stress-time history curves of the cement-soil compacted pile, CFG pile and soil between piles are all regular serrated shape, the vertical dynamic stress of CFG pile changes greatly, but the vertical dynamic stress of cement-soil compacted pile and soil between piles does not change much; the vertical displacement of CFG pile, cement-soil compacted pile and soil between piles change very little.

• 대한건축학회논문집:구조계
• /
• 제35권12호
• /
• pp.137-148
• /
• 2019

Korean piloti-type buildings are comprised of pilotis in the first story and shear walls in the upper stories. This vertical irregularity causes excessive lateral plastic deformation on the first story while the upper stories stay elastic. Meanwhile, asymmetric position of structural components such as core walls and columns of RC piloti-type buildings tends to produce torsional irregularities of the structures. Korean Building Code(KBC2016) requires the special seismic load and torsional amplification factor to apply to the piloti-type buildings lower than six-story or 20m if it has vertical and torsional irregularities when the building corresponds to seismic design category C or D. Many Korean low-rised RC buildings fall into the class. Therefore, the special earthquake load and torsional amplification factor are often applied to a building simultaneously. However, it has not been studied enough how much influence each parameter has on buildings with vertical and torsional irregularities at the same time. The purpose of this study is to evaluate the effect of factor special seismic load and torsional amplification on seismic performance of irregular buildings. In this study, a damaged 4^th story piloti-type building by the Pohang earthquake was selected and the earthquake response analysis was carried out with various seismic design methods by the KBC 2016. The effect of the design parameters on seismic performance was analyzed by the dynamic analysis of models with special seismic load and torsional amplification factor based on the selected building. It was concluded that the application of the torsional amplification factor to the reference model to which special seismic design was applied, does not significantly affect the seismic performance.

• 대한토목학회논문집
• /
• 제30권2A호
• /
• pp.121-129
• /
• 2010

본 연구에서는 고감쇠 고무받침 시험체의 다양한 특성실험을 통하여 전단특성 의존성을 파악하였다. 파악하고자 하는 고감쇠 고무받침의 특성은 변위의존성, 면압 의존성, 주파수 의존성, 온도 의존성 등이다. 특성실험결과 고감쇠 고무받침의 특성치는 온도에 가장 큰 영향을 받는 것으로 나타났으며, 주파수가 증가할수록 전단강성과 등가감쇠비 모두 증가하나 반복횟수가 증가 할수록 고무의 온도상승으로 인하여 그 값들은 감소하였다. 그리고 면압이 증가할수록 유효강성은 감소하고 등가감쇠비는 증가하는 것으로 타나났다. 본 실험결과에 의하면 고감쇠 고무받침의 설계의 주요한 변수인 전단강성과 등가감쇠비를 산정함에 있어 설계변위와 가진속도 및 온도의 면밀한 검토가 필요하다고 판단된다.

• 한국한의학연구원논문집
• /
• 제18권3호
• /
• pp.87-93
• /
• 2012

Objectives : The present study is to verify whether the deformation of ear acupuncture needle tips that are currently on the market is caused during the process of initial packaging. Methods : Ear acupuncture needles distributed from three different companies were collected to measure the size of the groove on the transparent plate which is used in for the intial packaging. Then the tolerance range for off-centered tips, which represent the range of the groove size that is safe from damaging the needle tip, was determined based on the vertical length measured from tip to handle. 200 ear acupuncture needles were dipped in alcohol and scanned to confirm the position of the needles. Stereo-microscope was used to observe the needle tips that were located outside the tolerance range. Results : The increased number of ear acupuncture needle tips placed outside the tolerance range were seen from in the order of C company, A company and B company. The increased deformation of the needle tips caused by initial packaging was observed in the order of A company, C company and B company. Conclusion : Only the ear acupuncture needles from B company showed the strong correlation between needle tip deformation and initial packaging. It has been observed that the deformation of the ear acupuncture needles is mainly due to manufacturing process, not the packaging process.

• 한국지반공학회논문집
• /
• 제34권4호
• /
• pp.13-25
• /
• 2018

앵커가 보강된 비탈면에 활동이 발생한 경우에는 활동면을 따라 전단면에 전단응력과 휨 응력이 작용하게 되고, 전단변형의 증가는 앵커의 긴장력 변화를 야기한다. 본 연구에서는 전단에 따른 앵커의 긴장력 변화를 확인하기 위해 앵커의 수직방향으로 전단변형을 유발하여 앵커의 긴장력을 측정하는 방법으로 대형 직접전단시험기를 통해 전단시험을 수행하였다. 전단시험은 앵커 설치 유무, 정착부에서 전단면까지의 이격거리(1D, 2D, 4D) 및 측압(0.1MPa, 0.2MPa)을 변수로 총 8가지 조건에 대해 시험을 실시하였다. 전단시험 결과, 이격거리와 주변지반의 측압은 앵커가 설치된 모형 지반의 전단력 및 앵커의 긴장력에 영향을 미치는 것으로 나타났으며, 전단력 변화는 앵커 두부 및 선단부의 축력변화와 관련이 있음을 규명하였다. 따라서 앵커 두부에서의 긴장력 변화 경향을 분석함으로써, 간접적으로 앵커 정착부에서의 전단변형에 따른 거동을 예측할 수 있음을 확인하였다.

• 한국지반신소재학회논문집
• /
• 제12권4호
• /
• pp.35-44
• /
• 2013

본 연구에서는 개량토 벽면공을 활용한 보강성토사면의 거동에 대하여 실내모형시험 및 수치해석을 통해 분석하였다. 또한 수해발생현장에 이 연구에서의 방법을 이용하여 시험시공으로 보강성토사면을 구축한 후 약 6개월간 전면변위를 측정하여 실제 거동을 분석하였다. 실내모형시험, 수치해석, 현장시험 등을 통해 개량토 벽면공의 강성은 보강성토사면에서 충분한 벽면공의 역할을 수행할 수 있는 것으로 나타났고, 시험시공 후의 전면변위 측정결과 사면높이에 대한 수평변위의 비율은 최대 약 0.4%로 매우 안정적인 것으로 조사되었다.

• 한국지진공학회논문집
• /
• 제24권2호
• /
• pp.95-102
• /
• 2020

Electrical instruments and devices contained in cabinets for controlling nuclear power plants require seismic qualification; likewise, in-cabinet response spectrum (ICRS) is necessary. Gupta et al. (1999) suggested the Ritz method, where rocking, frame bending, and plate bending behaviors of cabinets are considered, as a method for determining ICRS. This research proposes a method to determine the rocking stiffness of cabinets, which represents its rocking behavior. The cabinet is fixed on mounting frames and is connected to the base concrete by anchors. When horizontal excitation is applied to the cabinet, the mounting frames at anchors are locally deformed, the mounting frames are bent, and then rocking in the cabinet becomes evident. A method to determine equivalent vertical spring stiffness representing the local deformation of the mounting frames at anchors is then proposed. Subsequently, the rocking stiffness of this mounting frame is calculated upon assumption of the mounting frame as an indeterminate beam.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 봄 학술발표회 논문집
• /
• pp.607-614
• /
• 2000

Settlement with crack on the hardened liners may occur in the weak clay due to waste load since the stiffness of the hardened liner is greater than that of the clay layers. Way of reducing deformation crack in the hardened liner is investigated using two computer programs, CONSOL and FLAC. The computer program CONSOL estimates the magnitude of settlement with time in clay layers and FLAC analyses the stress and deformation relationship between the foundation of landfill and waste load. The results show that a representative block of the analyzed area reaches the consolidation settlement of 1.32m, 8.8 years after the disposal of waste started with the degree of consolidation U=90%. The stress within the hardened liner exceeds the allowable vertical stress of 5kg/$\textrm{cm}^2$ and horizontal stress of 1.67kg/$\textrm{cm}^2$ at the concave part of the liner where the main and branch drainage pipes of leachate are located. It was recognized that the thickness of the interested area should be enlarged or the strength of the same area should be improved to tolerate the planned waste load.

• 한국의류학회지
• /
• 제41권1호
• /
• pp.98-115
• /
• 2017

This study categorizes the formative aspects of dress and their implications according to the extent of revealing or concealing corporeality based on body perceptions. By considering the notion of dress as bodily practice to be a theoretical and methodological framework, this study combines a literature survey and case analysis to analyze and classify the forms of women's dress since the 1920s when contemporary fashion took hold. As examined in this study, the typology of dress was categorized as body-consciousness, deformation, transformation, and formlessness. Body-consciousness that is achieved through tailoring, bias cutting, and stretchy fabric displays corporeality focusing on the structure and function of the body as an internalized corset. Deformations in dress are categorized into two different subcategories. One is the expansion or reduction of bodily features based on the vertical or horizontal grids of the body, which visualizes the anachronistic restraint of the body through an innerwear as outerwear strategy. The other is exaggerations of the bodily features irrelevant to the grid, which break from the limitations and constraints of the body as well as traditional notions of the body. Transformations of the body refer to as follows. First, the deconstruction and restructuring of the body that deconstruct the stereotypes in garment construction. Second, the abstraction of the body that emphasizes the geometrical and architectural shapes. Third, transformable designs which pursue the expansion and multiplicity of function. Formlessness in dress denies the perception of three-dimensionality of the body through the planarization of the body.

• Computers and Concrete
• /
• 제9권2호
• /
• pp.133-151
• /
• 2012

This paper presents an analytical procedure for the analysis of high strength steel fiber reinforced concrete members considering the cracking effect in the serviceability loading range. Modifications to a previously proposed formula for the effective moment of inertia are presented. Shear deformation effect is also taken into account in the analysis, and the variation of shear stiffness in the cracked regions of members has been considered by reduced shear stiffness model. The effect of steel fibers on the behavior of reinforced concrete members have been investigated by the developed computer program based on the aforementioned procedure. The inclusion of steel fibers into high strength concrete beams and columns enhances the effective moment of inertia and consequently reduces the deflection reinforced concrete members. The contribution of the shear deformation to the total vertical deflection of the beams is found to be lower for beams with fibers than that of beams with no fibers. Verification of the proposed procedure has been confirmed from series of reinforced concrete beam and column tests available in the literature. The analytical procedure can provide an accurate and efficient prediction of deflections of high strength steel fiber reinforced concrete members due to cracking under service loads. This procedure also forms the basis for the three dimensional analysis of frames with steel fiber reinforced concrete members.