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         "type" : "Publication",
         "id"   : "https://puma.ub.uni-stuttgart.de/bibtex/29fa32fdbc6429900820d9a550952ad85/petraheim",         
         "tags" : [
            "2010","advanced","diss","dissertation","engineering","forschungsbericht","grid","hwang","investigation","itke","shell","spatial","structure"
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         "intraHash" : "9fa32fdbc6429900820d9a550952ad85",
         "interHash" : "d0b08347c5da29bf15f973866384be2f",
         "label" : "Advanced Investigations of Grid Spatial Structures",
         "user" : "petraheim",
         "description" : "",
         "date" : "2020-06-24 14:07:20",
         "changeDate" : "2021-07-01 13:01:14",
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         "pub-type": "phdthesis",
         "series": "Forschungsberichte aus dem Institut für Tragkonstruktionen und Konstruktives Entwerfen","publisher":"Stuttgart: Institut für Tragkonstruktionen und Konstruktives Entwerfen","address":"ITKE, Stuttgart, Germany",
         "year": "2010", 
         "url": "", 
         
         "author": [ 
            "Kyung-Ju Hwang"
         ],
         "authors": [
         	
            	{"first" : "Kyung-Ju",	"last" : "Hwang"}
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         "editor": [ 
            "Jan Knippers"
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         "editors": [
         	
            	{"first" : "Jan",	"last" : "Knippers"}
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         "volume": "31","abstract": "Free-form grid spatial structures and facades that follow the envelope surface of a complex-shaped skin, such as the DZ-Bank in Berlin (Frank 0. Gehry), the British Museum in London (Norman Foster), the My Zeil in Frankfurt (Massimiliano Fuksas), have become a very interesting issue in modern architecture. There are several important factors in such single layer lattice dome and complex-shaped spatial structures, for instance, optimal form finding and strong material strength and so forth, but the optimal design and analysis of connection are significant points in free-form spatial structures, because such extraordinary geometries and its continuously changing curvature can be defined by the angles of the connections' geometries, and the stiffness of connection can determine the stability of the whole free-form structure. Therefore, it is very important to recognize that the appropriate analysis and connection design have to be performed, in order to design the reasonable global single layer spatial structure and free-form spatial structures.\r\nGeneral procedures\r\nFor the FEA of four connection systems, bending stiffness (My and Mz) and axial force (F) tests were performed. These analyses include the modeling of the bolt assembly, the contact stiffness and the influence of bolt clearances, which were considered using two parameters, such that D..V=0.1 mm and 2.0mm. Due to a specific function of COMBIN39 in ANSYS, the moment-rotation behaviors and load-displacement curves could be transferred to nonlinear spring elements in global grid shells with 25 m and 50 m span that have three different rise-span ratios (0.1, 0.2 and 0.3), to realize the non linear characteristics of the connection systems.\r\n\r\nResults\r\nConnection system having two shear planes showed higher stiffness than those with one shear plane. On the other hand, node connectors with one shear plane were not as influenced by differing bolt-holes as those with two shear planes due to shape-of-joint behaviour. Secondly, the low connection stiffness with initial geometrical imperfection easily leads membrane stress to bending stress, so that the critical point of the grid shell occurred with low load failure factor. The influence of bolt clearance depends mainly on the node stiffness and rise-span ratio. The overall structural behavior of an imperfect high-rise grid shell can be very sensitive, displaying a large deviation of bending stiffness due to bolt clearances.",
         "isbn" : "978-3-922302-31-5",
         
         "language" : "eng",
         
         "bibtexKey": "hwang2010advanced"

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         "type" : "Publication",
         "id"   : "https://puma.ub.uni-stuttgart.de/bibtex/226f1ec9390a0245dacb4b4e464bbec11/petraheim",         
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            "2017","acttively","analysis","bent","diss","dissertation","engineering","form-finding","forschungsbericht","grid","itke","li","plate","segmental","shell","structural","structure","timber"
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         "interHash" : "b63b7f1729a68f2d49cf78422af4e9de",
         "label" : "Timber Shell Structures: Form-finding and Structural Analysis of Actively Bent Grid Shells and Segmental Plate Shells",
         "user" : "petraheim",
         "description" : "",
         "date" : "2020-06-23 16:38:28",
         "changeDate" : "2021-07-01 13:04:36",
         "count" : 2,
         "pub-type": "phdthesis",
         "series": "Forschungsberichte aus dem Institut für Tragkonstruktionen und Konstruktives Entwerfen","publisher":"Stuttgart: Institut für Tragkonstruktionen und Konstruktives Entwerfen","address":"ITKE, Stuttgart, Germany",
         "year": "2017", 
         "url": "", 
         
         "author": [ 
            "Li. Jian-Min"
         ],
         "authors": [
         	
            	{"first" : "Li.",	"last" : "Jian-Min"}
         ],
         
         "editor": [ 
            "Jan Knippers"
         ],
         "editors": [
         	
            	{"first" : "Jan",	"last" : "Knippers"}
         ],
         "volume": "42","abstract": "Shell structures are structurally efficient but difficult to manufacture and thus expansive. Actively bent grid shells and segmental plate shells could be alternatives. The first kind utilizes bended members to form a continuously curved geometry and thus reduce the complexity of the joints. The second kind utilizes the stability inherited in trivalent geometries to be able to build a shell without using bending stiff joints. Both these two types of timber shell structures could largely reduce the construction cost. That is why they are chosen as the research topics. The dynamic relaxation method (DR) is applied in this research as an important numerical method. It is used as the fundamental base for developing the form-finding tools of both actively bent grid shells\r\nand the segmental grid shells. A solver capable of the structural analysis of beam system is also developed here based on DR. Through the text, we show that DR could handle not only form-finding problems but also geometrically nonlinear analysis.\r\nThe dissertation consists of four parts. Part I is the introduction. Part II and Part III present both the form-finding and analysis techniques of these two types of timber shell structures. The last part is the conclusions.",
         "isbn" : "978-3-922302-42-1",
         
         "language" : "eng",
         
         "bibtexKey": "jianmin2017timber"

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         "type" : "Publication",
         "id"   : "https://puma.ub.uni-stuttgart.de/bibtex/29fa32fdbc6429900820d9a550952ad85/itke",         
         "tags" : [
            "2010","advanced","diss","dissertation","engineering","forschungsbericht","from:petraheim","grid","hwang","investigation","itke","shell","spatial","structure"
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         "label" : "Advanced Investigations of Grid Spatial Structures",
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         "series": "Forschungsberichte aus dem Institut für Tragkonstruktionen und Konstruktives Entwerfen","publisher":"Stuttgart: Institut für Tragkonstruktionen und Konstruktives Entwerfen","address":"ITKE, Stuttgart, Germany",
         "year": "2010", 
         "url": "", 
         
         "author": [ 
            "Kyung-Ju Hwang"
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         "authors": [
         	
            	{"first" : "Kyung-Ju",	"last" : "Hwang"}
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         "editor": [ 
            "Jan Knippers"
         ],
         "editors": [
         	
            	{"first" : "Jan",	"last" : "Knippers"}
         ],
         "volume": "31","abstract": "Free-form grid spatial structures and facades that follow the envelope surface of a complex-shaped skin, such as the DZ-Bank in Berlin (Frank 0. Gehry), the British Museum in London (Norman Foster), the My Zeil in Frankfurt (Massimiliano Fuksas), have become a very interesting issue in modern architecture. There are several important factors in such single layer lattice dome and complex-shaped spatial structures, for instance, optimal form finding and strong material strength and so forth, but the optimal design and analysis of connection are significant points in free-form spatial structures, because such extraordinary geometries and its continuously changing curvature can be defined by the angles of the connections' geometries, and the stiffness of connection can determine the stability of the whole free-form structure. Therefore, it is very important to recognize that the appropriate analysis and connection design have to be performed, in order to design the reasonable global single layer spatial structure and free-form spatial structures.\r\nGeneral procedures\r\nFor the FEA of four connection systems, bending stiffness (My and Mz) and axial force (F) tests were performed. These analyses include the modeling of the bolt assembly, the contact stiffness and the influence of bolt clearances, which were considered using two parameters, such that D..V=0.1 mm and 2.0mm. Due to a specific function of COMBIN39 in ANSYS, the moment-rotation behaviors and load-displacement curves could be transferred to nonlinear spring elements in global grid shells with 25 m and 50 m span that have three different rise-span ratios (0.1, 0.2 and 0.3), to realize the non linear characteristics of the connection systems.\r\n\r\nResults\r\nConnection system having two shear planes showed higher stiffness than those with one shear plane. On the other hand, node connectors with one shear plane were not as influenced by differing bolt-holes as those with two shear planes due to shape-of-joint behaviour. Secondly, the low connection stiffness with initial geometrical imperfection easily leads membrane stress to bending stress, so that the critical point of the grid shell occurred with low load failure factor. The influence of bolt clearance depends mainly on the node stiffness and rise-span ratio. The overall structural behavior of an imperfect high-rise grid shell can be very sensitive, displaying a large deviation of bending stiffness due to bolt clearances.",
         "isbn" : "978-3-922302-31-5",
         
         "language" : "eng",
         
         "bibtexKey": "hwang2010advanced"

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         "type" : "Publication",
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            "2017","acttively","analysis","bent","diss","dissertation","engineering","form-finding","forschungsbericht","from:petraheim","grid","itke","li","plate","segmental","shell","structural","structure","timber"
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         "label" : "Timber Shell Structures: Form-finding and Structural Analysis of Actively Bent Grid Shells and Segmental Plate Shells",
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         "series": "Forschungsberichte aus dem Institut für Tragkonstruktionen und Konstruktives Entwerfen","publisher":"Stuttgart: Institut für Tragkonstruktionen und Konstruktives Entwerfen","address":"ITKE, Stuttgart, Germany",
         "year": "2017", 
         "url": "", 
         
         "author": [ 
            "Li. Jian-Min"
         ],
         "authors": [
         	
            	{"first" : "Li.",	"last" : "Jian-Min"}
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         "editor": [ 
            "Jan Knippers"
         ],
         "editors": [
         	
            	{"first" : "Jan",	"last" : "Knippers"}
         ],
         "volume": "42","abstract": "Shell structures are structurally efficient but difficult to manufacture and thus expansive. Actively bent grid shells and segmental plate shells could be alternatives. The first kind utilizes bended members to form a continuously curved geometry and thus reduce the complexity of the joints. The second kind utilizes the stability inherited in trivalent geometries to be able to build a shell without using bending stiff joints. Both these two types of timber shell structures could largely reduce the construction cost. That is why they are chosen as the research topics. The dynamic relaxation method (DR) is applied in this research as an important numerical method. It is used as the fundamental base for developing the form-finding tools of both actively bent grid shells\r\nand the segmental grid shells. A solver capable of the structural analysis of beam system is also developed here based on DR. Through the text, we show that DR could handle not only form-finding problems but also geometrically nonlinear analysis.\r\nThe dissertation consists of four parts. Part I is the introduction. Part II and Part III present both the form-finding and analysis techniques of these two types of timber shell structures. The last part is the conclusions.",
         "isbn" : "978-3-922302-42-1",
         
         "language" : "eng",
         
         "bibtexKey": "jianmin2017timber"

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