Study On The Bearing Capacity Of High Strength Bolt Connection For Longitudinal Seam Of Medium Wave Corrugated Steel Plates In Tunnel

Compared with conventional reinforced concrete pipe gallery,corrugated steel pipe gallery has many advantages including the bending capacity,tensile capacity and adaptability for various foundation types.It has been widely used for pipeline and culvert engineering,transportation engineering and storage engineering at home and abroad.At present,Most scholars at home and abroad have studied and analyzed the overall force and concrete structure of corrugated steel pipe gallery.The research on mechanical properties of high strength bolted connection of corrugated steel plate is less,and the ultimate bearing capacity is mostly given by concrete structure list,which is inconvenient for practical engineering design.So it is necessary to study the mechanical properties of the bolted connection,and put forward the calculation method of the longitudinal joint bearing capacity of corrugated steel plate,which can provide a reference for practical engineering design.In this paper,according to the?Cold-formed corrugated steel pipes??GB/T 34567-2017?standard,the size of medium wave 200mm*55mm is designed.The ultimate bearing capacity of longitudinal joints with high strength bolts was tested,and the flat plate specimens were designed under the same condition,hot-dip galvanized and non-galvanized steel plate with different thicknesses were considered.The failure mode,the ultimate load and slip load of the longitudinal seam,the limit displacement and slip displacement of the specimens were analyzed.Based on the test results,the finite element refinement model of the joints was established.The effects of bolt pretension,end spacing,plate thickness and waveform on the mechanical properties of the corrugated joints were discussed through the finite element parameter analysis.The results reveal that hot dip galvanizing had almost no effect on the ultimate load.When the specimen is subjected to pore wall pressure or end shear failure,the ultimate load of CSP connections was about 12%to 20%higher than that o f flat plate ones under the same conditions,and the limit displacement of the former is slightly larger than that of the latter.When the bolt screw shearing failure occurred,the ultimate displacement of the flat plate connections was about 1.3 to 1.7 times of the CSP ones,but the ultimate bearing capacity of both was similar.According to the test results and the analysis of finite element parameters.When bearing failure at bolt hole occurred,the ultimate bearing capacity increases with the increase of the pretension force of the high strength bolt,and the ultimate bearing capacity also increases with the increase of the thickness of the plate;When the bolt screw shearing failure occurred,the ultimate bearing capacity is less affected by bolt pretension and plate thickness.the bolt end spacing of the corrugated plate connector should be not less than 3d₀ to ensure that prevent end shear failure of connectors;It is suggested that the calculation formula of joint bearing capacity of corrugated plate connections be multiplied by the increase factor of 1.1 when bearing failure at bolt hole occurred.When the shear failure of bolts occurs,the ultimate shear bearing capacity of high strength bolted joints of corrugated plate joints is calculated according to the ultimate shear bearing capacity of flat plate joints in JGJ99-2015 code.