Investigation On Progressive Collapse-Resistant Performance And Reliability For Kiewitt Cable Domes

Cable dome structure is a highly efficient flexible structure system,which has become one of the hotspots in the field of spatial structure research and application in recent years.Research on the static performance,progressive collapse-resistance performance and reliability of Kiewitt cable dome structures are conducted in this paper,and the main contents are summarized as follows.(1)The singular value decomposition method and Full NR method are used to analyze the force-finding and loading history of Kiewitt cable dome structures.The influence of the setting of the internal tension ring and the change of the initial prestress level,the rise-span ratio and the length of the strut on the static performance are discussed.The results show that the relaxation of the inner ring ridges JS1 will cause a sudden change in the structural stiffness during the progressive loading of the full-span uniform load,but the structure can still maintain a strong bearing capacity.The inner ring can not only solve the problem of multi-bar intersection in the central part of the structure,but also effectively share the unloading force due to the relaxation of the inner ring ridges under external load.Increasing the initial prestress level,strut length and rise-span ratio can improve the vertical stiffness of the structure,and the latter is the most significant.In engineering practice,it is suggested to set up an inner ring and give priority to adjusting the geometric parameters of the structure to improve its static performance.(2)Using the transient dynamic analysis method to investigate the influence of local cablestrut rupture on the structural strain energy,the maximum vertical displacement of nodes and the internal forces of other cable-struts.The structural progressive failure process and collapse mechanism caused by local cable-strut rupture are revealed,and the classification of structural response modes after single cable-strut rupture is proposed.Results show that if the dynamic internal force in the oscillation process is ignored and only the internal force of the component in the final equilibrium state is considered,the calculation results will be unsafe.On the premise of determining the section of each group of cable rods according to the given optimization principle,the failure of a single cable rod causes different degrees of damage to the local stress system of the structure,but does not cause the overall collapse of the structure.The response modes of the structure can be divided into four categories: local failure,cable relaxation,smallscale collapse and large-scale collapse.In engineering practice,it is recommended to strengthen the safety reserves of JS2 K,HS2 and CG3,so as to improve the progressive collapse resistance of the structure.(3)Due to the limitations of the traditional sampling,the Sobol sampling is introduced.On this basis,the RSM and Kriging surrogate model are optimized,and the third-order RSMSobol method is proposed,which is applied to the reliability analysis of the deformation failure mode of the Kiewitt cable dome structure,and the third-order RSM-FORM method is used to analyze the reliability of the strength failure mode of the structure.In addition,the parameter analysis of the structure is carried out to explore the influence of the change of initial prestress level and deformation control value on the structural reliability index.The results show that the Sobol sampling has obvious advantages in calculation accuracy,stability and sample distribution uniformity,and the third-order RSM-Sobol method based on the Sobol sampling is suitable for deformation failure reliability analysis of cable dome structures.Since the deformation failure probability of the structure is much larger than the strength failure probability,the main failure mode is deformation failure.Appropriate increase of initial prestress level and relaxation of deformation control value can effectively improve the deformation failure reliability index of structure.The cable dome structure has large stiffness,which can meet the reliable index requirements specified in the current specification under strict deformation control conditions.