Study On Roof-Isolation Of Long-Span Space Truss Structure

Long-span space truss structure is a common structural form of large-scale public buildings,so the safety of this structure under earthquake action is very important.As an effective,economical and feasible new technology and system of structural seismic resistance,isolation technology is also effective in the application of long-span space truss structures.The common isolation schemes are base isolation and roof isolation.In this paper,the effect of base isolation and roof isolation on long-span space truss structures is studied.Further,the elasticplastic analysis of the non-isolation structure and the roof isolation structure of the long-span space truss is carried out to verify the isolation effect of the roof and the failure law of the nonisolation structure and the roof isolation structure.The main work is as follows:(1)The related research and research status of isolation technology in long-span space truss structures are discussed.(2)Taking the engineering example as the background,YJK and 3D 3S are used to establish the lower support structure and the upper grid structure respectively,and SAP2000 is used to carry out the finite element analysis of the whole model.Base isolation and roof isolation are adopted to design the whole structure.The results show that both schemes can significantly reduce the seismic response of the roof,but the base isolation structure excites more vertical components in a local area of the roof.The difference of seismic response between roof isolation structure and base isolation structure is studied comparatively.The results show that the effect of base isolation on the seismic response of the lower structure is obvious,and the roof isolation structure has a certain increasing effect on the seismic response of the lower structure.(3)Elastic-plastic analysis of long-span space grid structure with non-isolation and roof isolation shows that roof isolation structure can effectively protect the roof part under Fortification and rare earthquakes.For the lower braced structures,the two structures are always at the same level of performance(under the same earthquake),but the plastic development of roof isolation structures is higher.Therefore,roof isolation can effectively improve the seismic safety performance of long-span space truss structures.The hoop of the roof is a weak part,which should be strengthened properly in the design.