Research On The Seismic Performance Of Steel Truss Coupling Beams With Friction Devices

Coupling beam is the first defending line of seismic resistance in high-rise shear wall structures and frame-shear wall structures.Energy dissipation capacity and the ability to connect wall limbs of coupling beam are very important for the structure.In this paper,based on the research of solid-web steel coupling beams and traditional steel truss coupling beams,two new types of friction steel truss coupling beams are proposed.By combining the test and the finite element method,the seismic performance of two new types of friction steel truss coupling beams is studied,and the design method and simplified model of the friction steel truss coupling beams in the overall analysis are proposed.This paper firstly introduces the construction component and design concept of the bending-type FTCB.The seismic performance of concrete coupling beam,bending-type FTCB and common steel truss coupling beam is compared through the cyclic pseudo-static testing,and the effect of different span-to-height ratio of FTCB on seismic performance is studied.The test results show that the deformation and energy consumption of the bending-type FTCB are concentrated in the friction devices.Compared with concrete coupling beam and traditional steel truss coupling beam,bending-type FTCB has more stable hysteretic performance,energy consumption capacity and deformation capacity.In addition,the friction material of the bending-type FTCB was replaced after the first round of test,and the friction devices still work normally,which proves that the bending-type FTCB can achieve the purpose of quick repair after the earthquake.With the same design bearing capacity,the shear-type FTCB is also tested and analyzed through cyclic tests.The test results show that the shear deformation is the main deformation mode and the friction devices consume most of the deformation and energy of the shear-type FTCB,which brings stable hysteretic performance and energy consumption capacity.Compared with the common steel truss coupling beam,the chord and web members of the shear-type FTCB will remain elastic,which is conducive to the quick repair after the earthquake.On the basis of the above test results,fine FEM is established and verified to systematically study the resistance mechanism of two kinds of FTCB.The resistance mechanism of the FTCB is proofed that the axial force of the upper and lower chords resists the bending moment,and the vertical component of the axial forces of the web resist the shear force.The accuracy of the calculation formula for the shear strength and initial stiffness is verified,too.The simulation results also show that the FTCB can realize the decoupling of initial stiffness and shear strength,that is,the steel truss component controls the whole coupling beam initial stiffness,and the friction device sliding force controls the coupling beam shear strength.Based on the research results of experiment and finite element models,the design suggestions of the FTCB are proposed.By summarizing and refining the hysteretic behavior of the FTCB,a simplified hysteretic model is also proposed,and the relevant parameters and calculation methods are given.The rationality of the model is verified by the test data,which provides a reference for the later overall analysis.