| The prefabricated building has the characteristics of green and efficient construction,environmental protection,energy saving and emission reduction.It is a new type of building that meets the requirements of sustainable development,and is also an important way to realize the modernization of construction industry.With the advantages of flexible space arrangement,high efficiency of transportation and installation,prefabricated concrete frame structure is one of the most widely used forms of prefabricated structure.However,the earthquake hazards shows that the joint area and connection part of prefabricated concrete frame are always the weak link in seismic design,and the RC frame structure is prone to the layer yielding mechanism causing by "strong beam and weak column" under the earthquake.In this paper,a new type of prefabricated artificial dissipative plastic hinge frame-rocking wall(ADPH-RW)structural system,has been proposed,which aims to improve the seismic performance of the structure while adapting to the efficient construction characteristics of prefabricated buildings.By optimizing the deformation mode of the structure through the artificial dissipative plastic hinge and the rocking wall,the prefabricated concrete frame structure has the advantages of high energy dissipation and low damage.In this study,physical tests,numerical simulations and theoretical derivations are used to systematically study and evaluate the seismic performance of the artificial energy dissipative plastic hinge frame-rocking wall structure,from 4 level such as configuration,joint,frame and System,from the local part to the whole.The main work and innovation points of the paper are as follows.(1)Configuration level.Artificial dissipative plastic hinge is proposed,which consists of a mechanical hinge and an additional energy dissipative steel plate,and its seismic performance is studied by a combination of the pseudo-static test and finite element simulation.The results show that the damage mode is the tearing damage of the slotting section after the additional steel plate is buckled under pressure;the ADPH has stable hysteresis characteristics,better ductility and ultimate rotation capacity under reciprocating load,and can realize the outward movement of the plastic hinge and damage control;the use of stiffening ribs can prevent the additional steel plate from being buckled under pressure prematurely,and obviously improve bearing capacity and energy dissipation capacity.In the Open SEES model,the fiber beam-column element of Hysteretic material is used to simulate the additional dissipative steel plates,and the zerolength element simulates the mechanical hinge,which can simulate the hysteretic behavior of the artificial dissipative plastic hinge accurately.(2)Joint level.The experimental study of artificial dissipative plastic hinge frame joint was carried out,and the seismic performance was studied by combining finite element simulation and theoretical analysis.The results show that the ADPH joint can control the plastic damage in the middle slotting section of the additional steel plate,avoiding the damage in the core area of the joint,and the damage mode is the severe buckling and slight tearing in the middle slottin section of the additional steel plate during the reciprocal tension and compression;the ultimate bearing capacity of the ADPH joint is increased by about 30%,compared with cast-in-place RC joints,the ductility is increased by more than 28%,the hysteresis curve is relatively fuller,the energy dissipation capacity is enhanced,and the degradation of stiffness is slower;the additional steel plate still has stiffness and strength after flexure since the stiffening rolled edge,Premature buckling can easily lead to the bent form of both sides of the steel plates,causing the appearance of slippage and reduction of energy efficiency,the out-of-plane deformation should be controlled to avoid it;The established finite element model established by using ABAQUS software can simulate the hysteretic behavior well of the proposed ADPH joint.According with the force analysis of the ADPH joint,the yield moment reduction factor ? is introduced to optimize the joint.It is shown that the joint can maximize the energy dissipation capacity and control the plastic damage of the non-energy dissipating members when ? is approximated in the range of 0.75 to 0.85.The simplified finite element model of the joint established by Open SEES can effectively improve the computational efficiency on the basis of accurate simulation of the hysteresis behavior of the joint.(3)Frame level.The specimens of prefabricated frame with ADPHs and the prefabricated frame-rocking wall structure with ADPHs were designed and fabricated respectively,and the pseudo-static test of them were carried out,simulated and verified by the finite element model.The results show that the damage mode of all four specimens is the expected "beam hinge" damage mechanism,and the plastic damage is concentrated in the ADPH at the beam end of each floor,the dissipative steel plate at the prefabricatied column foot,and the connecting beam between the rocking wall and the frame,and the joint area is basically intact;the ADPH-RW structure has good ultimate bearing capacity.The specimens with cast-in-place column footings has higher bearing capacity,while the specimens with prefabricated column foot has higher ductily,bearing capacity degrades more slowly;the rocking wall structure has less influence on the initial stiffness and ultimate bearing capacity of the specimens with cast-in-place column foot,and has a more obvious improvement of the specimens with prefabricated column foot.Ductility coefficient of the specimens is greater than 4.0,the drift angle corresponding to the peak load is more than 1/25,and the ultimate drift angle is more than 1/20;the degradation of the specimen stiffness mainly originates from the buckling of the stiffening rolled edge of the additional steel plate flange and the cumulative damage of the column foot concrete,the buckling of the stiffening rolled edge,resulting in the need to offset part of the compressed residual deformation before the steel plate is pulled into the strengthening stage,the limiting steel plate limits the flexural deformation of the additional steel plate,reduces the range of slip section,and makes the hysteresis curve fuller;the finite element model established by ABAQUS finite element software is in good agreement with the test results in terms of deformation mode,damage mode,hysteresis curve,crack development and strain;the simplified model established by Open SEES software has better simulation results,and the calculation efficiency is significantly improved,on the basis of better simulation results.(4)Structural system level.The seismic performance of the ADPH-RW model was evaluated by static pushover analysis,dynamic time-history analysis and incremental dynamic analysis.The results show that the load-bearing capacity of the ADPH structure is significantly improved,and the ultimate displacement and ductility are greatly improved,further improved by adding the rocking wall structure.The maximum inter-story drift angle is significantly reduced by 48.5% compared with that of the reinforced concrete frame structure,and the inter-story drift concentration coefficient is reduced by 47.7%;the ADPH-RW structure has excellent yielding mechanism.Through the ADPH and rocking structure,the damage deformation is concentrated at the ADPH,and the beams and columns is no damage or slight damage;the collapse resistance of the ADPH-RW structure is significantly stronger than that of the RC structure. |
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