Analysis Of Static Stability And Construction Simulation For Long-Span Cable Supported Cylindrical Reticulated Shells With Partial Members Omitted

Cable supported cylindrical reticulated shells are new structure system which are formed by double-layer cylindrical lattice shells with partial members omitted and the lower cable-strut of string segment.It has been applied in engineering practice successfully which combines with the advantages of double-layer cylindrical lattice shells and beam string structure.Those structures are taken as the research object and study of the static behaviors,static stability and construction simulation of the structures in this thesis.The main contents are summarized as follows:(1)A new method of force-finding analysis for cable supported cylindrical reticulated shells is presented,which is called distribution renewal method based on the Discrete Newton Method.This new method is verified by examples and the result is compared with the traditional tension compensation method,then the control parameters determined by different prestress are optimized.On the basis,the static behaviors are investigated respectively by considering changes of support style and string-to-span ratio.The studies show that distribution renewal method based on the Discrete Newton Method has fast computational speed and high precision.Based on the initial state,the control parameter of the vertical displacement of top chord midspan of latticed frame arch of string segment closes to zero as the force finding analysis method of the structures is more reasonable.Due to the lower cable-strut of string segment,the stiffness of double-layer cylindrical lattice shells are enhanced significantly and the axial stress of chord members are reduced effectively.As the increase of the number of supporting edges,the stiffness and support horizontal reaction change little under the full-span load,axial stress of double-layer cylindrical lattice shells and internal force of cable-strut increase in turn,and the ability to resist asymmetric load is enhanced.As the increase of string-to-span ratio,the stiffness of the structure is increasing,axial stress of double cylindrical shells and support horizontal reaction are significantly reduced.Considering the relevant regulations of structural clearance,cable tension and reasonable span of beam string structure,it is recommended that the stringto-span ratio should not exceed 66.7% in engineering practice.(2)Double nonlinear static stability of the ideal structures of cable supported cylindrical reticulated shells and its imperfect structures which merely consider installation deviation of nodes(overall imperfections for short)are studied,and compared with the corresponding ordinary double-layer cylindrical lattice shells.The influence of the change of parameters on imperfect structures which merely consider overall imperfections is discussed.On the basis,introducing the initial curvature of bars,and the influence(couple)of rotation angle and amplitude of bars on the stability bearing capacity of the ideal structures and imperfect structures which merely consider overall imperfections is further studied.The analysis shows that cable supported cylindrical reticulated shells are insensitive to overall imperfections.As the increase of the number of supporting edges,the stability bearing capacity coefficients of the ideal structures and imperfect structures which merely consider overall imperfections increase continuously.Increasing the string-to-span ratio of cable supported cylindrical reticulated shells can improve the stability of the structure considering overall imperfections.It's sensitive to the initial curvature of bars for cable supported cylindrical reticulated shells,it is suggested to consider the influence of initial curvature of bars in engineering practice.It has a coupling effect on the stability bearing capacity of the structure when overall imperfections and initial curvature of bars are introduced at the same time,weaken the detrimental influence to some extent of two kinds of imperfections when introduced separately.The interaction between overall imperfections and rotation angle of initial curvature of bars is significant.(3)The construction simulation analysis for cable supported cylindrical reticulated shells is carried out by using one-step and three-step tension methods respectively.The results indicate that the initial strain determination method based on Discrete Newton Method is suitable for the construction simulation analysis for cable supported cylindrical reticulated shells,and can better solve the influence of excessive prestress loss on the iterative process.Compared with the one-step tension method,the gradients of displacement and internal force by using threestep tension method are relatively small,and the tension of each cable changes gently to the value of design cable force,which is beneficial to the forming of the structure,although it is more complex.In engineering practice,it is suggested to adopt the three-step tension method.