| With the development of building structure design,truss transfer floor is used more and more because of its advantages such as overall stability,large lateral stiffness,good mechanical performance and full utilization of space advantages.Compared with the common truss structure,the open-web truss is a good conversion form when the architectural appearance has design requirements.Open-web truss structure has the advantages of light weight,large span,large space,strong bearing capacity and simple appearance.The application of open-web truss transfer structure in construction engineering is increasing gradually,but there is no clear design regulation for this structure in existing codes in China,which limits its application in engineering.It is of great research significance and value to design the hollow truss structure under horizontal and vertical earthquakes and analyze the subsequent seismic performance.The main research contents and conclusions of this paper are as follows:(1)A variety of different models are established,and static analysis is carried out on the large-span SRC vierendeel truss layer.The stress of each truss member is analyzed,and corresponding structural measures are put forward according to its stress.The analysis shows that the stiffness of the open-web truss transfer floor itself is large,and each member of the transfer floor has greater stress and stronger bearing capacity than the frame members,but the stiffness of the open-web truss transfer floor can not be too large,so reasonable structural stiffness should be chosen to make its stress reasonable.(2)In view of a practical project,the elastic-plastic time-history analysis of large-span SRC vierendeel truss transfer floor is carried out.Seven different seismic waves are selected,and the lateral displacement and maximum displacement angle between stories of the structure under the action of three-dimensional fortification earthquake and rare earthquake are analyzed,and the specific weak layer position of the structure is obtained.The analysis shows that the inter-story displacement angles are less than the limit value.Combined with the target evaluation criteria given in the code,the failure state of the vertical members of the open-web truss structure is between slight failure and key failure,which shows that the structure has good integrity,can resist the damage caused by large earthquakes,and has good seismic performance,and can meet the basic requirements of seismic performance at all stages.(3)The finite element software is used to simulate and analyze the composite joint formed by the lower chord beam and the frame strut of the vierendeel truss,and the finite element model is established.By applying reciprocating load to the column end,the results show that the concrete is crushed or cracked first because of the high stiffness of the joint of the steel composite beam,and the failure of the joint first appears from the beam-column junction,and gradually develops to the core area,and the steel bars and steel bars yield,which shows that the joint has high bearing capacity and good ductility. |
