Blast Loading And Failure Mechanism Of Single-layer Reticulated Dome Subjected To Interior Blast

Long-span spatial structures are widely used in all kinds of the public facilities, such as stadiums, transportation junctions, airport terminations, exhibition centers, industrial buildings and so on. Recently, the blast events raised by terrorist attacks and accidents occurred frequently, which resulted in the failure and collapse of civil constructions. As the landmark of the city, the long-span spatial structures symbolize the political significance. And they are always the activity places of huge crowds of people at the same time. If this kind of important places occurred by terrorist blast attacks, heavy losses would be generated in the emergency. Overall, the long-span spatial structures would be the targets of terrorist attacks much easily, which makes that the research of the blast loading and dynamic responses of long-span spatial structures are significant.However, almost the existing research focused on the dynamic responses of those simple members and small structures, the studies on blast responses of long-span spatial structures are still scarce at present. And there are still a lot of problems in this field. For example, the blast loads are varying according to the sharps of the targets, so the existing data cannot give the blast loading for the long-span spatial structures. Besides, there is no blast tests relative to long-span spatial structures, which results in that the accuracy of blast simulations in long-span spatial structures is not certain. Thirdly, the failure mechanism is not clear, it means that no effective advises and comments can be made to the current design process. Last, because of the restrictions of calculating capacity of the computers, the fluid-structure interaction(FSI) method is poor efficiency in the analysis process, which makes more problems based on large samples cannot be launched. Consequently, take the study of single-layer reticulated dome under central interior blast loading as an example, the main contents of this research are listed as following.(1) Because that there are no blast test relative to the long-span spatial structures, a series of scale blast tests about pressure field of curved structure subjected to blast loading were launched. The numerical model for blast loading in reticulated shells was set up, and the blast loading values were verified by the blast test data. From the comparison results, the conclusion was obtained that the parameters and methods used in AUTODYN package could well simulate the confined blast problems.(2) The difference of equivalences of TNT charges and environments of the structures make the uncertain character of each terrorist attack. Therefore, using FSI method is not real for every possible case. On the basis of the features of blast loading, the main parameters of blast loading which finally controls the blast responses were fixed. Then, a method for obtaining blast loading via other geometric similarity models was used. A series of parameter studies were launched to explore the rules of blast loading distribution. Finally, an accuracy and convenient model was setup based on the parameter studies results, which can be widely used for estimating the blast loading on different reticulated domes.(3) Blast loading is a kind of sudden loads, which applies on the structures when they are in the static equilibrium state under gravity. Because the large span of spatial structures, the stiffness in the vertical direction of the dome is a bit weak than the other traditional buildings. Thus, there must more considerations in the blast resist designing process. Based on these reasons, a method could consider the gravity effect was raised in this thesis to analysis the dynamic responses of the reticulated domes. Five different failure modes were defined from amount of numerical samples, the failure mechanisms and occurrence rules have been also investigated.(4) The reticulated domes were composed by lots of members, which are multi degree of freedom statically indeterminate system. The theoretical analysis method is not as easy as using in those simple systems. In this thesis, two simple and basic structures were taken as the basis by using theoretical analysis methods to study the counter-intuitive problems during blast actions. Then the conclusions were also verified by numerical samples as well. These explain the reason why the counter-intuitive collapse taken in the special ranges of the full-range dynamic response analysis. Furthermore, the reason of single-layer reticulated dome subjected to central interior blast loading were revealed, which lays the foundation for the further research and the blast resist design.