索承网壳结构是目前跨度最大的空间结构形式,是一种由一系列连续拉索和间断压杆组成的索杆张力结构。Geiger型索承网壳结构的布置呈轮辐状布置,由环索和径向索组成,形式简单,施工难度低。Levy型索系的布置方法是对Geiger型的改进,改由...索承网壳结构是目前跨度最大的空间结构形式,是一种由一系列连续拉索和间断压杆组成的索杆张力结构。Geiger型索承网壳结构的布置呈轮辐状布置,由环索和径向索组成,形式简单,施工难度低。Levy型索系的布置方法是对Geiger型的改进,改由环索和斜索组成,索系稳定性显著提高且施工难度变化不大,因此,近年来设计建造的索承网壳结构大多采用Levy型。无内环索承网壳结构中索的平面投影呈直线而传力直接,索直接与外部支承点相连而彼此独立,局部断索后其余拉索仍保持受力状态,索与索相互交叉而形成整体,局部断索后,与之相交的拉索充当了备用荷载传递路径,阻止了初始损伤的蔓延,当跨度较大时可采用多层无环索型索系组合。在经济指标方面,无环索方案更有优势。通过查阅国内外文献资料,总结相关结构研究进展,本文通过建立、优化Levy型开敞式索承网壳结构、Geiger型开敞式索承网壳结构、无环索型开敞式索承网壳结构Midas有限元分析模型,分析初始几何缺陷对开敞式索承网壳结构静力稳定性的影响、荷载分布对静力稳定性的影响,比较不同索系开敞式索承网壳结构在断索后的静力稳定性差异,比较不同索系开敞式索承网壳结构动力特性的差异。结果表明:三种结构的初始缺陷越大,结构破坏时的荷载倍数越大,结构达到极限承载力时发生的竖向位移越大。这三种结构在荷载分布分为满跨、相邻半跨、相对半跨、1/4跨共4种情况下,它们达到极限承载力的趋势相近;开敞式Geiger型索承网壳结构和开敞式无内环索承网壳结构屋面活荷载按相对半跨作用于结构上时,结构在很小的竖向位移下就发生了失稳,最不利;这三种结构在屋面活荷载作用于结构1/4跨时,结构破坏时的竖向位移最大。这三种网壳结构,断最内部的索,相对而言最安全,越往外越不利。三种结构的模态越低,结构振动频率越低,结构的阵型越少,结构刚度越大。Cable-supported reticulated shell structure is currently the largest-span spatial structure form, which is a cable-rod tension structure composed of a series of continuous cables and intermittent compression rods. The Geiger-type cable-supported reticulated shell structure is arranged in a spoke-like manner, consisting of annular cables and radial cables, with a simple form and low construction difficulty. The arrangement method of the Levy-type cable system is an improvement of the Geiger-type, which is changed to be composed of ring cables and diagonal cables. The stability of the cable system has significantly improved, and the construction difficulty has not changed much. Therefore, most of the cable-supported reticulated shell structures designed and constructed in recent years adopt the Levy type. In the cable-supported reticulated shell structure without an inner ring, the plane projection of the cable is a straight line and the force is directly transmitted. The cables are directly connected to the external support point and are independent of each other. After local cable breakage, the other cables still remain in a stressed state. The cables intersect with each other to form a whole. After local cable breakage, the intersecting cables act as a backup load transmission path, preventing the spread of the initial damage. When the span is large, a multi-layer non-loop cable type combination can be adopted. In terms of economic indicators, the non-loop cable scheme has more advantages. By reviewing domestic and foreign literature, the research progress of related structures is summarized. In this paper, the Midas finite element analysis models of the Levy type open cable-supported reticulated shell structure, the Geiger type open cable-supported reticulated shell structure, and the non-annular cable type open cable-supported reticulated shell structure are established and optimized. The influence of the initial geometric defect on the static stability of the open cable-supported reticulated shell structure and the influence of the load distribution on the static stability are analyzed. The differences in the static stability of the open cable-supported reticulated shell structures with different cable systems after cable breakage are compared, and the differences in the dynamic characteristics of the open cable-supported reticulated shell structures with different cable systems are compared. The results show that the larger the initial defect of the three structures, the larger the load multiple when the structure is damaged, and the larger the vertical displacement when the structure reaches the ultimate bearing capacity. When the load distribution of these three structures is divided into four cases: full span, adjacent half span, opposite half span, and 1/4 span, their trends of reaching the ultimate bearing capacity are similar;when the live load on the roof of the open Geiger-type cable-supported reticulated shell structure and the open-type cable-supported reticulated shell structure without an inner ring acts on the structure according to the relative half span, the structure will be unstable under a very small vertical displacement, which is the most unfavorable;when the live load on the roof acts on the 1/4 span of the structure, the vertical displacement of the structure is the largest when the structure is damaged. For these three reticulated shell structures, breaking the innermost cable is relatively safe, and the more outward it is, the more disadvantageous it is. The lower the mode of the three structures, the lower the structural vibration frequency, the fewer the structural formations, and the greater the structural stiffness.展开更多
文摘索承网壳结构是目前跨度最大的空间结构形式,是一种由一系列连续拉索和间断压杆组成的索杆张力结构。Geiger型索承网壳结构的布置呈轮辐状布置,由环索和径向索组成,形式简单,施工难度低。Levy型索系的布置方法是对Geiger型的改进,改由环索和斜索组成,索系稳定性显著提高且施工难度变化不大,因此,近年来设计建造的索承网壳结构大多采用Levy型。无内环索承网壳结构中索的平面投影呈直线而传力直接,索直接与外部支承点相连而彼此独立,局部断索后其余拉索仍保持受力状态,索与索相互交叉而形成整体,局部断索后,与之相交的拉索充当了备用荷载传递路径,阻止了初始损伤的蔓延,当跨度较大时可采用多层无环索型索系组合。在经济指标方面,无环索方案更有优势。通过查阅国内外文献资料,总结相关结构研究进展,本文通过建立、优化Levy型开敞式索承网壳结构、Geiger型开敞式索承网壳结构、无环索型开敞式索承网壳结构Midas有限元分析模型,分析初始几何缺陷对开敞式索承网壳结构静力稳定性的影响、荷载分布对静力稳定性的影响,比较不同索系开敞式索承网壳结构在断索后的静力稳定性差异,比较不同索系开敞式索承网壳结构动力特性的差异。结果表明:三种结构的初始缺陷越大,结构破坏时的荷载倍数越大,结构达到极限承载力时发生的竖向位移越大。这三种结构在荷载分布分为满跨、相邻半跨、相对半跨、1/4跨共4种情况下,它们达到极限承载力的趋势相近;开敞式Geiger型索承网壳结构和开敞式无内环索承网壳结构屋面活荷载按相对半跨作用于结构上时,结构在很小的竖向位移下就发生了失稳,最不利;这三种结构在屋面活荷载作用于结构1/4跨时,结构破坏时的竖向位移最大。这三种网壳结构,断最内部的索,相对而言最安全,越往外越不利。三种结构的模态越低,结构振动频率越低,结构的阵型越少,结构刚度越大。Cable-supported reticulated shell structure is currently the largest-span spatial structure form, which is a cable-rod tension structure composed of a series of continuous cables and intermittent compression rods. The Geiger-type cable-supported reticulated shell structure is arranged in a spoke-like manner, consisting of annular cables and radial cables, with a simple form and low construction difficulty. The arrangement method of the Levy-type cable system is an improvement of the Geiger-type, which is changed to be composed of ring cables and diagonal cables. The stability of the cable system has significantly improved, and the construction difficulty has not changed much. Therefore, most of the cable-supported reticulated shell structures designed and constructed in recent years adopt the Levy type. In the cable-supported reticulated shell structure without an inner ring, the plane projection of the cable is a straight line and the force is directly transmitted. The cables are directly connected to the external support point and are independent of each other. After local cable breakage, the other cables still remain in a stressed state. The cables intersect with each other to form a whole. After local cable breakage, the intersecting cables act as a backup load transmission path, preventing the spread of the initial damage. When the span is large, a multi-layer non-loop cable type combination can be adopted. In terms of economic indicators, the non-loop cable scheme has more advantages. By reviewing domestic and foreign literature, the research progress of related structures is summarized. In this paper, the Midas finite element analysis models of the Levy type open cable-supported reticulated shell structure, the Geiger type open cable-supported reticulated shell structure, and the non-annular cable type open cable-supported reticulated shell structure are established and optimized. The influence of the initial geometric defect on the static stability of the open cable-supported reticulated shell structure and the influence of the load distribution on the static stability are analyzed. The differences in the static stability of the open cable-supported reticulated shell structures with different cable systems after cable breakage are compared, and the differences in the dynamic characteristics of the open cable-supported reticulated shell structures with different cable systems are compared. The results show that the larger the initial defect of the three structures, the larger the load multiple when the structure is damaged, and the larger the vertical displacement when the structure reaches the ultimate bearing capacity. When the load distribution of these three structures is divided into four cases: full span, adjacent half span, opposite half span, and 1/4 span, their trends of reaching the ultimate bearing capacity are similar;when the live load on the roof of the open Geiger-type cable-supported reticulated shell structure and the open-type cable-supported reticulated shell structure without an inner ring acts on the structure according to the relative half span, the structure will be unstable under a very small vertical displacement, which is the most unfavorable;when the live load on the roof acts on the 1/4 span of the structure, the vertical displacement of the structure is the largest when the structure is damaged. For these three reticulated shell structures, breaking the innermost cable is relatively safe, and the more outward it is, the more disadvantageous it is. The lower the mode of the three structures, the lower the structural vibration frequency, the fewer the structural formations, and the greater the structural stiffness.
