The Theoretical And Experimental Study Of A New Kind Of Support For Grid Structures

Grid structure is a kind of lightweight space structure.And they are used widely at home and abroad nearly half a century. The overall stiffness and economic and technical indicators of the structure are excellent.The structure can provide a wealth of architectural styles.Various stadiums, train stations, convention centers,industrial plants and other large-span buildings choosed grid structures.The nodes are key parts of the grid structures,and the supports nodes are the key parts of the nodes of the structures. A variety of support forms have been proposed recently, including spherical support, plate support, pin support, rubber mats supports,axle support and pot-type support,and so on,and bolt spherical supports are the most widely used.To release the horizontal reaction force, long holes are provided in the carrier plate of the traditional supports, so as to produce a certain amount of sliding. Because of the large friction between the upper covering plate and the lower embedded plate especially in rust, the traditional bolt-ball sliding supports in grid structures usually can not slide at all,which can not achieve the desired goals.And the engineering accidents led by this are common,such as a gas station in ShenYang collapsed after a big snow because of the moment at the column foot(caused by horizontal tension) exceeded the ultimate bearing capacity.And a gas station in NanYang collapsed under wind load,which was also caused by moment at the column foot.These engineering accidents will lead serious economic losses.The new support in this papper used PTFE and stainless steel plate.To make the support can slide under the horizontal reaction force by taking advantage of the small friction between them and the stainless characteristic,which solved the problems encountered in traditional supports.This paper described the current situation and prospect of its research and application of the grid structures and the support nodes,gave an overview of the current research on the supports for the grid structures at home and abroad,and completed the following research works:(a)Developing two new types of unidirectional sliding supports on the basis of extensive researches.(b)We processed the model of the new type of support,then we did research about the sliding property and bearing capacity of the new type of support.And the results showed that the sliding property was good and the bearing capacity of the new type of support could also met the using requirements.(c)Completing the modeling work of the support through universal finite element analysis software ANSYS.(d)Doing nonlinear finite element analysis about the support which connected by high-strength bolts under the vertical load,and got the failure modes of the support under the ultimate load,and the positions of the support which reached the ultimate compressive strength and yielded first were the ribs of it. Then we did comparative analysis about the experimental results and the theoretial results,got the bearing capacity and failure modes of it.The key parts of this article is all about the new type of supports which are connected by high strength bolts.The overall performance and research parts of the other new type of support are similar to it,so we did not do duplicate researchs about it in this article.