Study On Connection Performance Of Integrated Floor Truss Beam And Beam

Based on a practical project in Henan province,this article makes an in-depth study on the connection of integrated floor steel truss beams.The steel truss uses Ushaped steel as the upper,lower chord member and diagonal member,the end rods use square steel tubes,and the truss is hinged or rigidly connected to the main beam or column.The connection is made of high-strength bolts.The connection node of this kind of truss secondary beam is changed compared with the solid web secondary beam.The connection form of the secondary beam structure has changed.It is directly connected to the square steel pipe with high-strength bolts.The mechanical performance of the high-strength bolts in the joint is more complicated.In order to study the mechanical performance of this form of connection,this paper has conducted an in-depth study on the shear resistance of the high-strength bolt group to the square steel tube and the anti-slip resistance of the high-strength bolt according to the actual connection structure.In this paper,through experiments,finite element simulation analysis and theoretical calculations,the shear strength of high-strength bolts in the connection structure of truss secondary beams and the mechanical performance of primary and secondary beam connection nodes are systematically studied.The specific contents are as follows:(1)According to the mechanical characteristics of the direct connection between high-strength bolts and square steel pipe in this paper,the performance and calculation methods of friction type high-strength bolts are analyzed and summarized.Including the application method of pretension of friction type connection high-strength bolt and the failure characteristics of friction type connection high-strength bolt.The results show that the change of structural form may affect the torque coefficient and the antislip coefficient of the contact surface of the high-strength bolt.(2)The torque coefficient and anti-slip coefficient of high-strength bolts with sleeved square steel tube structure were tested,six groups of high-strength bolts with sleeve structure were selected,and three sets of axial directions for anti-slip coefficients of the contact surface shear test and three sets of torque coefficient tests,analyze the influence of this structure on the pretension of high-strength bolts and the anti-slip coefficient of the contact surface.(3)The torsion-shear performance test of the primary and secondary beams was carried out on the connection nodes of the truss secondary beams and the traditional structural nodes.The test content includes the material property test,the torsional shear test of the primary and secondary beams under the truss secondary beam construction form and the torsional shear test of the primary and secondary beams under the solid web secondary beam construction form,contrast and analyze the influence of the truss secondary beam connection node construction form on the bearing capacity and node stiffness of the primary and secondary beam connection nodes.Based on the test results,a simplified constraint method for the two ends of the truss secondary beam nodes in the calculation of high-strength bolt connections is proposed.(4)The finite element sub-nonlinear analysis software was used to numerically analyze the high-strength bolt shear nodes and the primary and secondary beam connection nodes under the truss secondary beam construction form.In the highstrength bolt shear joints,the influence of several main parameters of the truss secondary beam connection node on the high-strength bolt shear performance was analyzed;in the primary and secondary beam connection nodes,the influence of different types of high strength bolt connections is discussed and the applicability of the calculation method for truss secondary beam connections is verified.(5)For the bolt-connected secondary beam truss,the finite element analysis of the support constraint position at the truss vertical rod and the node of the member is carried out respectively,and the influence of the bolted truss vertical rod on the internal force of the truss is compared and studied.For the truss,the internal force of the members near the vertical rod is greatly affected.