Seismic Behaviour Of Steel Energy-dissipating Hinge And New Type Of Assembly Joint With Steel Energy-dissipating Hinge

As a research hotspot in recent years,precast concrete structure has the advantages of high production efficiency,fast construction schedule,less construction waste,energy conservation and environmental protection.As an important connecting components in the precast concrete structure,the beam-column joints should have good performance.But due to the current practice,in mechanical properties,most of the joints could not surpass the performance of castin-place concrete.Also,it is difficult to achieve the seismic design requirements of "strong column and weak beam",makes the joints often be the weak parts of the structure.Therefore,a new type of steel energy-dissipating hinge,which has the characteristics of plastic controllable,strong energy dissipation,easy to install and detachable,was proposed.Applying it to the prefabricated beam-column joints makes it easier for the joins to meet the seismic design requirements of the "strong column and weak beam" and protect the core area of the joints from damage.The following research has been done on this essay:(1)The experimental study on two different energy-dissipating hinges under cyclic loading were carried out to study the load-deformation hysteresis curve,bearing capacity degradation,stress-strain distribution and development,rotational stiffness,ductility and failure modes of the energy-dissipating hinge.The results show that the hysteresis curves of two energydissipating hinges are both in plump shapes and have no obvious pinching effect..The average ductility of the two energy-dissipating hinges is above 6,the intensity degradation is not obvious and the energy dissipation coefficient is above 3.The energy-dissipating hinges have good bearing performance and hysteresis characteristic.(2)The finite element analysis model of the energy-dissipating hinges were established by using the ABAQUS finite element software.The failure mode,bearing capacity,limit rotation angle,energy dissipation performance and working mechanism of energy-dissipating hinges were studied.The bending moment-rotation hysteresis curve and failure mode calculated by finite element method are basically consistent with the experimental results.At the same time,the influence of weakening degree,weakening range and length of energy-dissipating hinge on hysteresis performance of energy-dissipating hinges were also studied.According to the results of the parameter analysis,the reasonable design value of the energy-consuming hinge is obtained.Based on the mechanical characteristics of energy dissipation hinge,the simplified mechanical model of energy dissipation hinge is given.The moment-rotation restoring force model of energy dissipation hinge is put forward.And the validity of the proposed restoring force model is proved by validating the restoring force model.(3)An experimental study was carried out on the fabricated joints with different energydissipating hinges and cast-in-place joints under cyclic loading.Repeated experiments had been carried out on the fabricated joints with T-shaped energy-dissipating hinge.The experimental results show that the hysteretic curves of fabricated joints with energy-dissipating hinges are full,while the hysteretic curves of cast-in-place joints have obvious pinch phenomenon.The average ductility of the fabricated joint and the cast-in-place node is similar.The strength of the fabricated joint is not significantly degraded,while the cast-in-place node has significant strength degradation.The energy consumption of a fabricated joint is significantly higher than that of a cast-in-place joint.After the repeated test of the assembled joint,the performance was basically the same except for the previous stiffness.It can be stated that after the energy consuming component is destroyed,the structure can be restored to the original bearing capacity by simply replacing the energy consuming component.(4)The finite element analysis model of fabricated joints with energy-dissipating hinges were established by using the ABAQUS finite element software.The failure mode,stress distribution,plastic development and working mechanism analysis of fabricated joints were studied.The load-displacement curve and the failure mode calculated by the finite element method are basically consistent with the experimental results.The results of numerical simulation show that the first yield section of the assembly joint with T-shaped and dog-bone energy-dissipating hinge is the maximum cross section of the flange at the energy dissipation hinge.The plastic development is also concentrated in the area of the flange weakening region.The reasonable design of energy dissipation hinge can make the joint had plastic controllability,and can control the failure position of the joint.A design method for fabricated concrete joints with energydissipating hinges is proposed.