Study On Method For Enhancing Resistance To Vertical Disaster Of Plate Type Truss Structure

The grid structure is a space steel structure product composed of many bars connecting with each otherby nodes with a certain form. It has so many advantages such as less weigh, high stiffness, excellentperformances of ductility and seismic resistance, rapid construction speed, low engineering cost and so on.With the rapid development of China’s economic construction, the grid structure is widely appliedto various industrial and civil constructions and public constructions. However, as natural disastersappeared frequently in recent years, the grid structure accidents occurred more and more resulting in thedamage to people’s lives and property. So people begin to pay attention on how toenhance the anti-disaster ability of the grid structure. The21mx21m Square Pyramid Space GridsStructures with surrounding columns is analyzed systematically to find out the important bars and takemeasures to improve the anti-disaster ability.In order to find out the location of important bars the top chord, down chord and web member is dividedinto three regions of the middle, edge and corner. After removing bars in all regions the change of theinternal force, the yield load and the ultimate load conduct the analysis research.The alternate path method is used to analyze the different degree influence of the bars on the situation ofthe internal force under the normal load. That is, after bars in the structure divided into multiple seriesaccording to the location, the importance of the bars can be distinguished by comparison to the change of theinternal force after removing every serie of bars.Then, in determining the ultimate load of the structure the alternate path method and load incrementmethod are used. The importance of the bars can be distinguished by comparison to the change of the ultimate load after removing every serie of bars.According to the analysis of the change of the internal force and the ultimate load after removing everyserie of bars, the location of important bars can be identified. Then the design method for enhancing theanti-disaster capacity of the structure can be proposed.Finally, the ultimate bearing capacity and situation of yield bars of the strengthened structure isanalyzed and compared to the value of the original structure. It shows that the ultimate bearing capacity ofthe grid structure can be effectively improved when the steel consumption increase lowly.