• Title/Summary/Keyword: single-layer domes

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The dynamic response and seismic damage of single-layer reticulated shells subjected to near-fault ground motions

  • Zhang, Ming;Parke, Gerry;Chang, Zhiwang
    • Earthquakes and Structures
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    • v.14 no.5
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    • pp.399-409
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    • 2018
  • The dynamic response and seismic damage of single-layer reticulated shells in the near field of a rupturing fault can be different from those in the far field due to the different characteristics in the ground motions. To investigate the effect, the dynamic response and seismic damage of this spatial structures subjected to two different ground motions were numerically studied by nonlinear dynamic response analysis. Firstly, twelve seismic waves with an apparent velocity pulse, including horizontal and vertical seismic waves, were selected to represent the near-fault ground motion characteristics. In contrast, twelve seismic records recorded at the same site from other or same events where the epicenter was far away from the site were employed as the far-fault ground motions. Secondly, the parametric modeling process of Kiewitt single-layer reticulated domes using the finite-element package ANSYS was described carefully. Thirdly, a nonlinear time-history response analysis was carried out for typical domes subjected to different earthquakes, followed by analyzing the dynamic response and seismic damage of this spatial structures under two different ground motions based on the maximum nodal displacements and Park-Ang index as well as dissipated energy. The results showed that this spatial structures in the near field of a rupturing fault exhibit a larger dynamic response and seismic damage than those obtained from far-fault ground motions. In addition, the results also showed that the frequency overlap between structures and ground motions has a significant influence on the dynamic response of the single-layer reticulated shells, the duration of the ground motions has little effects.

Effects of geometrical initial imperfection in proportioning member sections of single layer reticulated dome (단층 래티스 돔의 단면산정에 있어서의 형상초기불완전의 영향)

  • Kim, Jong-Min;HwangBo, Seok;Han, Sang-Eul;Kwun, Teak-Jin
    • 한국공간정보시스템학회:학술대회논문집
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    • 2004.05a
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    • pp.83-88
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    • 2004
  • First author proposed a proportioning method for member sections of a single layer reticulated dome subjected to uniform and non-uniform load without any geometrical initial imperfection, and discussed the validity and effectiveness of the method which was based on linear buckling stress and a knock down factor. However, buckling of a single layer reticulated dome is strongly affected by initial imperfection. It is well known that geometrical initial imperfections reduce the nonlinear buckling capacity of a single layer raticulated dome. Thus, structural engineers may be recommended to reflect the effects of geometrical initial imperfections in proportioning member sections. In this paper, firstly, the presented proportioning method by first author is applied to dome without consideration of any imperfections and the thickness and diameter of each member are determined. Secondly, the load bearing capacities of the proportioned domes are checked with the imperfection, by the inelastic buckling analysis.

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A Study on the Presumption of Geometrically Nonlinear Buckling Load of the Single Layer Latticed Dome (단층 래티스 돔의 기하학적 비선형 좌굴하중 추정에 관한 연구)

  • Lee, Jung-Hyun;Lee, Sang-Ju;Lee, Jin-Sub;Choi, Il-Sub;Han, Sang-Eul
    • Proceeding of KASS Symposium
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    • 2005.05a
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    • pp.147-153
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    • 2005
  • The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition, and the connection type because it is originazed by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling of the structures is analyzed. But, it is very difficult to design the single layer latticed domes considered all conditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base of the linear buckling load by the eigenvalue analysis.

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Buckling Analysis for Single Layer Latticed Domes considering the Change of Joint Rigidity (접합부 강성변화를 고려한 단층 래티스 돔의 좌굴해석)

  • 이후진;권택진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.337-344
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    • 2001
  • This paper is concerned with the change of joint rigidity in estimating the degree of semi-rigidity of connections and the buckling load in a single layer latticed dome. The estimations are based on information about the ratio for the rotational stiffness of the connection to the flexural stiffness of the member and the minimum eigenvalue of a structure for pinned, semi-rigid and completely rigid cases, respectively. Connection characteristics are reflected in the ratio control of joint rigidity for the DOFs to be related using the spring element by FEM.

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A Study on the Presumption of Geometrically Nonlinear Buckling Load of the Single Layer Layer Latticed Dome (단층 래티스 돔의 기하학적 비선형 좌굴하중 추정에 관한 연구)

  • Lee Jung-Hyun;Choi Il-Sub;Lee Sang-Ju;Han Sang-Eul
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2005.04a
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    • pp.12-19
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    • 2005
  • The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition and the connection type because it is organized by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling behavior of the structures is analyzed But, it is very difficult to design the single layer latticed domes considered all conditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base on the linear buckling load by the eigen-value analysis.

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A Study on Effect of the Junction's Eccentricity for Buckling Characteristics of Single-Layer Latticed Dome (접합부 편심을 고려한 단층 래티스돔의 좌굴특성에 관한 연구)

  • Park, Sang-Hoon;Suk, Chang-Mok;Jung, Hwan-Mok;Kwon, Young-Hwan
    • Journal of Korean Association for Spatial Structures
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    • v.1 no.1 s.1
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    • pp.117-124
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    • 2001
  • In Single-layer latticed domes with rectangular network which is composed of ring of circumferential direction and rafter of longitudinal direction, that is, rib domes, if we use the cross-membered junction's method for the advantage in fabrication and construction, the eccentricity is occurred in the nodal point of crossing members. This paper is aimed at investigating the buckling characteristics for the effect of eccentricity according to rise-span ratios and distance of eccentricity. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems. The conclusion were given as follows: 1. The maximum decreasing ratio of buckling strength due to the junction's eccentricity is about 60% in models of this paper. 2. In the increasing ratio of buckling strength for rise-span ratio, that of Type 3 models is larger than that of type 2 models. On the other hand, that of Type 2 mode is larger than that of Type 3 for eccentricity-distance. 3. In the viewpoint of the value of buckling strength, that of Type 2 models is larger than that of type 3 models. The effect of the junction's rigidity on buckling strength is not great for overall models. Therefore if we use the cross-membered junction's method for the advantage in fabrication and construction, the method of Type 2 will have the great advantage of that of Type 3.

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A Study on the Bucking Load Formulae for the Single Layer Latticed Dome (단층 래티스 돔의 좌굴하중 산정식에 관한 연구)

  • Han, Sang-Eul;Yang, Jae-Geun;Lee, Sang-Ju;Lee, Jung-Hyun
    • Journal of Korean Association for Spatial Structures
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    • v.6 no.1 s.19
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    • pp.75-82
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    • 2006
  • The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition, and the connection type because it is organized by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling of the structures is analyzed. But, it is very difficult to design the single layer latticed domes considered all renditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base of the linear buckling load by the eigenvalue analysis.

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A Study on Buckling Characteristics of 2-way Grid Single-Layer Domes Considering Rigidity-Effect of Roofing Covering Materials (지붕마감재 강성효과를 고려한 2방향 그리드 단층돔의 좌굴특성에 관한 연구)

  • Park, Sang-Hoon;Suk, Chang-Mok;Jung, Hwan-Mok;Kwon, Young-Hwan
    • Journal of Korean Association for Spatial Structures
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    • v.2 no.1 s.3
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    • pp.85-92
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    • 2002
  • Two way grid single-layer domes are of great advantage in fabrication and construction because of the simple fact that they have only four members at each junction. But, from a point of view of mechanics, the rectangular latticed pattern gives rise to a nonuniform rigidity-distribution in the circumferential direction. If the equivalent rigidity is considered in the axial direction of members, the in-plane equivalent shearing rigidity depends only on the in-plane bending rigidity of members and its value is very small in comparison to that of the in-plane equivalent stretching rigidity. It has a tendency to decrease buckling -strength of dome considerably by external force. But it is possible to increase buckling strength by the use of roofing covering materials connected to framework. In a case like this, shearing rigidity of roofing material increases buckling strength of the overall structure and can be designed economically from the viewpoint of practice. Therefore, the purpose of this paper, in Lamella dome and rectangular latticed dome that are a set of 2-way grid dome, is to clarify the effects of roofing covering materials for increasing of buckling strength of overall dome. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems. The conclusion were given as follows: 1. In case of Lamella domes which have nearly equal rigidity in the direction of circumference, the rigidity of roofing covering materials does not have a great influence on buckling-strength, but in rectangular latticed domes that has a clear periodicity of rigidity, the value of its buckling strength has a tendency to increase considerably with increasing rigidity of roofing covering materials 2. In case of rectangular latticed domes, as rise-span-ratio increases, models which is subjected to pressure -type-uniform loading than vertical-type-uniform loading are higher in the aspects of the increasing rate of buckling- strength according to the rate of shear reinforcement rigidity, but in case of Lamella dome, the condition of loading and rise-span-ratio do not have a great influence on the increasing rate of buckling strength according to the rate of shear reinforcement rigidity.

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Determination of Member Force Ratios for Self-equilibrium State of Multi-Layered Cable Dome Type Structures (다층 케이블 돔형 구조물의 자기평형을 위한 부재력 비율 결정)

  • Kim, Jae-Yeol
    • Journal of Korean Association for Spatial Structures
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    • v.13 no.2
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    • pp.75-82
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    • 2013
  • For each cable component in a cable dome structure, pre-tension is needed for stability of whole the structure. The summation of these pre-tension at each joint should be zero to achieve the self equilibrium structure. The first step in cable dome structure analysis is to find the ratio of pre-tension in each member which can produce a stable and structure on self-equilibrium. In this paper, a new method based on the basic principle of closed force polygon for equilibrium system is proposed for the determination of self-equilibrium mode of cable dome structure. A single layer cable dome and two multi layer type domes have been analyzed. The ratios of cable members are determined by the presented method, and check the validation of the results by numerical calculation.

An Experimental Study on the Buckling & Behaviour of Single-Layer Latticed Dome (단층 래티스 돔의 좌굴 및 거동에 관한 실험적 연구)

  • Kim, Cheol-Hwan;Jung, Hwan-Mok
    • Journal of Korean Association for Spatial Structures
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    • v.6 no.4 s.22
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    • pp.35-44
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    • 2006
  • The form-resistant Systems like a dome and shell are used more widely than post-beam structure system in large space structure. Single layer latticed dome system, one of the form-resistant system, has great merits in manufacturing and constructing but the failure mechanism is not clarified yet. The purpose of this paper is to find out the buckling characteristics of single-layer latticed domes with square network by using the experimental method. Major test parameters are the stiffness of lattice member and space of square lattice. The specimens are applied uniform loading of snow type.

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