Mechanical Property Analysis Of Prestressed Assembled Concrete Structure With Additional Energy-dissipating Rods

The unbonded prestressed prefabricated structure has the disadvantages of insufficient energy consumption.To this end,this paper proposes a non-bonded prestressed prefabricated joint with additional energy-dissipating rods to improve the seismic performance of the prefabricated structure.The energy dissipation system is mainly composed of energydissipation rods and ribbed T-shaped connectors,which are connected by bolts,and has the advantages of simple structure and easy construction.In addition,a reinforcement model with high simulation accuracy is developed in this paper,and the seismic performance of cast-inplace,prefabricated and hybrid prefabricated joints are compared and analyzed using this model.Based on the above results,the joints are applied in the frame structure,and the static and dynamic elastoplastic analysis of the cast-in-place frame,the prefabricated frame and the hybrid prefabricated frame is carried out.The contents are summarized as follows:1.A reinforcement model based on Clough constitutive is proposed,which considers both the cohesive slip between the reinforcement and concrete and the strength degradation of reinforcement.This model is implemented in ABAQUS by embedding my developed UMAT subprogram and is applied to simulate the longitudinal reinforcement of beams in cast-in-place joints and prefabricated joints.The simulation results are in good agreement with the experiments,indicating that the developed model has high accuracy.2.Hysteretic simulation under repeated loads is carried out for cast-in-place joints,prefabricated joints and hybrid prefabricated joints with additional energy-dissipation rods.The failure modes,energy dissipation,ductility,stiffness degradation and residual deformation are studied.The energy consumption level of the hybrid prefabricated joint is significantly higher than that of the conventional prefabricated joint.The energy consumed by the energy dissipation system accounts for about 72.2% of the total energy consumption,and the stiffener of the T-shaped connector can increase the maximum viscous damping by nearly 8%.It shows that the energy-dissipation rods and stiffeners in the energy dissipation system both have excellent energy dissipation capacity.Increasing the reinforcement ratio of energy-dissipating rods increases the bearing capacity and energy-dissipation capacity of hybrid prefabricated joints,while decreases the self-reset deformation capacity.When the initial prestress is increased,the stiffness and maximum viscous damping of the hybrid prefabricated joints are improved and the ductility is decreased.The cumulative energy consumption of the joints increases slightly due to the limited energy consumption of plastic deformation of precast concrete.3.The static pushover analysis of the cast-in-place frame,the prefabricated frame and the hybrid prefabricated frame with additional energy-dissipation rods is carried out.The bearing capacity of the hybrid prefabricated frame is close to that of the cast-in-place frame.Its floor displacement,vertex displacement and inter-story displacement angle are smaller than those of the prefabricated frame but closer to the cast-in-place frame.It shows that the addition of energy-dissipation rods can increase structural rigidity and bearing capacity of the hybrid prefabricated frame,which can resist greater earthquakes.Both the hybrid prefabricated frame and the cast-in-place frame can form a high-energy-consuming "beam hinge" mechanism,which reflects the plastic deformation of the additional energy-dissipating rods in the joint area has a great improvement in the energy dissipation capacity of the prefabricated structure.4.The dynamic time-history analysis of the cast-in-place frame,the prefabricated frame and the hybrid prefabricated frame is carried out.It shows that the hybrid prefabricated frame is smaller than the prefabricated frame in terms of vertex displacement and interlayer displacement angle,but it is closer to the cast-in-place frame.The result shows that the seismic response of the hybrid prefabricated frame is small,and its seismic performance is better than that of the directly prefabricated frame and similar to that of the cast-in-place frame.In addition,comparing the above three residual deformations,it shows that the unbonded prestressed prefabricated structure has an excellent self-resetting ability.