| The occlusive high strength bolted connection is a new type of connection used in the field of supports and hangers,which has no need of drilling and convenient installation.Due to the lack of relevant research,the tensile bearing capacity of the occlusive high-strength bolted connection can only be determined through experiments in current engineering,which is a stopgap measure and needs to be solved theoretically.In order to clarify the tensile failure mechanism of the occlusive high-strength bolted connection and give the calculation method of the tensile bearing capacity,this thesis uses the experiment and the finite element method to carry out the parameter analysis and research respectively.The test includes a single bolt tensile test and a typical connection tensile test,a total of 72 specimens,considering the influence of four parameters of channel section specification and wall thickness,bolt specification and installation torque.The results of the tensile test of a single bolt show that the normal failure mode of the test piece is the formation of a plastic hinge line at the edge line of the channel steel on both sides;the wall thickness of channel steel has a significant effect on the bearing capacity,and the section size of channel steel has less impact on the bearing capacity;none of the bolts is damaged,and the installation torque has no effect on the bearing capacity.The results of the typical connection tensile test show that in addition to the plastic hinge formed by the channel steel,the angle iron connector is also prone to bending failure,and the prying force of angle iron on the crimp is obvious,which can prevent the curling edge from generating excessive displacement and avoid the premature formation of plastic hinge line.After comparing and verifying the finite element results with the test results,10 series and more than 30 finite element specimens were designed for the tensile strength of a single bolt and the tensile strength of a typical connection,and analyzed the influence of parameters such as the channel steel section specifications and wall thickness,bolt specifications and installation torque,the fixed distance of the bottom bolts of the channel steel,the wall thickness of the angle iron and the end distance of the bolt holes and other parameters on the tensile bearing capacity.The results of the numerical analysis of single bolt tensile strength show that the length of each plastic hinge line can be 100 mm,which has nothing to do with the channel steel specifications and wall thickness,bolt specifications and installation torque,and the bolt installation spacing at the bottom of the test piece.The results of numerical analysis of typical connection tensile strength show that in addition to the wall thickness of the channel steel,the wall thickness of the connection angle iron is also a controlling factor that affects the tensile bearing capacity;increasing the end distance of the angle iron bolt hole can effectively reduce the prying force.According to the results of the test and finite element analysis,the theoretical calculation method and design suggestions for the tensile bearing capacity of the occlusive high-strength bolted connection are given,and the comparison verification is carried out.It is safe and easy to use,which can be used as a reference for the support and hanger engineering designers. |
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