| In recent years,a lot of affordable housing has been built with property development above the metro depot in many cities to relieve the pressure of limited land resource and meet the housing demand in the cities.As the subway station segment sparse network,the interval is relatively large,and the upper part of the residential area of the residential column dense network,resulting in the overall structure of the upper and lower stiffness irregularities,in which case the need for residential and residential connections at the conversion layer structure.However,the existence of conversion layer will damage inherent continuity of lateral resisting element vertically and complicate both force transmission path and stress state.Under seismic action,there will be a sudden change in horizontal force of each floor and concentrated elastoplastic deformation because of conversion layer and therefore there will be weak layers evidently.Then the use of which type of conversion layer structure can make the structure of the smallest deformation,the best mechanical performance is the design needs to be given priority.This article takes affordable housing project with property development above Henggang depot of Shenzhen metro as an example.Truss conversion layer has finally been chosen between these two design schemes: beam type and truss type.In this paper,the finite element software SATWE and ABAQUS are used to establish the integral model and the local conversion beam model of the beam conversion layer and truss conversion layer.The mechanical properties of these two conversion layers are compared to show the feasibility of using truss conversion layer.In this paper,key indicators and main conclusions are as follows:(1)Using SATWE to build the beam conversion layer and truss conversion layer of the overall model of the structure,respectively,the two structures of the vertical static load,wind resistance and structural seismic performance were compared and found that the two conversion layer program Which conforms to the design requirements.However,the truss transformation layer has better vertical stiffness thanthe beam conversion structure in the conversion layer,and the effect of the truss type conversion structure on the vertical bearing capacity of the structure is more obvious.At the transition layer,it can be seen that the lateral stiffness of the two models produces a large mutation,and the degree of abrupt change of the beam structure is more intense.(2)Using ABAQUS finite element software to convert the structure of the shaft member to take a cross-modeling,stress-strain analysis of two conversion layer.In the case where only the vertical load is considered,the maximum equivalent stress appears at the middle of the converted beam.Since the larger equivalent stress is concentrated in the position of the bearing at both ends of the girder,the plastic hinge will first appear at the beam end under the action of external force.The bottom of the shear wall at the right end of the connecting beam and the upper residential structure also produces a large equivalent stress.This shows that under the action of the earthquake,the damage of the upper frame structure of the conversion layer will take precedence over the conversion layer,which can make the structure absorb more energy in the earthquake.Based on the comparison of the mechanical properties of the two models,it is found that the structure of the truss can be used to reduce the structure along the vertical stiffness,and the energy of the earthquake is better released,and it is more save material and reduce project budget.So the final selection of the truss structure is reasonable. |
