| Precast assembled shear wall system is one of the important structural systems in the construction industry for achieving the transformation of new and old kinetic energy.The existing precast concrete structures often adopt "wet connection" methods such as grouted sleeves and restrained grout anchors,but there are issues such as high connection cost,complex construction,difficult installation,difficult guarantee of grouting quality,and inability to construct in winter in cold regions.To overcome the limitations of the existing "wet connection" methods in precast concrete structures,the research team proposes a precast concrete shear wall system with "dry connection" using special-shaped steel tube concrete short columns as connectors with bolt connections.The feasibility and effectiveness of the proposed connection method are verified through quasi-static tests.Based on this,this paper further studies the seismic performance of the precast shear wall with special-shaped steel tube concrete bolted connections using numerical simulation analysis,and the main research contents and results are as follows:(1)Finite element analysis models of precast shear walls with special-shaped steel tube concrete connectors were established using three types of multi-vertical-leg members,namely MVLEM(multi-vertical-leg embedded model),SFI-MVLEM(strong-floor interface multi-vertical-leg embedded model),and MVLEM-3D(three-dimensional multi-vertical-leg embedded model),based on the OpenSees analysis platform.Numerical simulation analysis of the seismic performance of the shear walls was carried out.By comparing the finite element analysis results with the experimental results,it was found that all three types of multi-vertical-leg members could achieve accurate numerical simulation analysis of the proposed precast shear wall structure,with an error in bearing capacity of less than 10%.However,the shear wall model established using MVLEM-3D element was more detailed,and the seismic performance indicators matched well with the experimental results,validating the reliability and accuracy of the modeling method selected in this study.(2)Based on the finite element analysis model developed in this study,the influence of eight key parameters,including axial compression ratio,shear-span ratio,wall thickness,connection length,connection height,steel tube thickness,concrete strength,and steel reinforcement strength,on the seismic performance of precast shear walls with irregular steel tube-concrete connections was investigated.The results showed that within the allowable range of axial compression ratio,the peak load-carrying capacity of the shear wall specimens increased significantly with a lower axial compression ratio,but the increment reduced when the axial compression ratio was higher.As the shear-span ratio decreased,the peak load-carrying capacity and seismic performance of the specimens improved significantly.For shear walls with a shear-span ratio less than 2,the SFI-MVLEM element provided better simulation results considering the bending-shear coupling effect.With an increase in wall thickness,the geometric dimensions of the connections changed accordingly,and the increase in the ultimate load-carrying capacity of the shear walls exhibited a linear distribution.The length and height of the connections had little influence on the overall ultimate load-carrying capacity and seismic performance of the shear walls.The load-carrying capacity of the shear walls did not increase further when the steel tube thickness of the connections reached 6mm.The increase in concrete strength and steel reinforcement strength had limited effect on the ultimate load-carrying capacity of the specimens.(3)Based on the results of the parameter analysis,this study proposes recommendations for the construction measures of the connecting members: the length of the connecting members should be designed according to the size of the corresponding edge members,and the height of the connecting members should be minimized while ensuring sufficient bolt connection;the steel tube thickness of the connecting members should be set at 6mm.In addition,this study proposes a design method for precast shear walls with irregular steel tube concrete connectors.Based on the existing theory,a simplified calculation model and design method for the flexural capacity of the positive section of precast shear walls are proposed,as well as a design method and construction requirements for the connecting members.A design method for the diagonal section shear capacity of precast shear walls is proposed based on the superposition method.A design method for irregular steel tube concrete connectors is proposed,and the shear capacity of horizontal joints is calculated,demonstrating that bolt connections do not experience slip failure under horizontal loads. |
PDF Full Text Request