| With the acceleration of urbanization around the world,people have higher and higher requirements for building safety.Prefabricated building has become a hot spot in the field of architecture because of its advantages of high efficiency,environmental protection and reusability.The most commonly used structural type of prefabricated buildings is frame structure,which consists of several bars and nodes,and the bars are connected together by bolts or welding at the nodes to form a spatial structure with high strength and stiffness.However,due to the particularity of its structure,this structure may have the problem of insufficient anti-progressive collapse performance,that is,after one node is destroyed or fails,the whole structure will collapse continuously,thus posing a threat to personal safety and property.In order to solve this problem,it is necessary to study the progressive collapse resistance of assembled frame structure,and explore the stress distribution,deformation characteristics and failure mode of the structure during the stress process,so as to provide a basis for optimal design and improve the progressive collapse resistance of the structure.Aiming at the above problems,this paper mainly does the following research and draws relevant conclusions:(1)Taking a new type of assembled frame structure with assembled joints as the research object,a plane substructure model is established by hypermesh/lsdyna finite element software to carry out numerical simulation analysis,and the calculated results are compared with the experimental data,thus verifying the correctness of the numerical model.Based on this,the performance of the three-dimensional frame structure connected by such nodes is analyzed.(2)For the cast-in-place concrete frame and the assembled concrete frame,different progressive collapse research methods are adopted to compare and analyze their progressive collapse resistance.Firstly,based on the alternative path method,through linear static analysis,the gravity load is applied to the remaining structure under the condition of removing the key columns(middle column and corner column)at the bottom,and the collapse resistance of the structure without the key columns is studied.The results show that,when the key columns are removed,the remaining structures above the failed columns of the cast-in-place structure and the assembled structure all move downward,but the overall stability of the structure is maintained.It shows the applicability of the assembled frame structure with this kind of node connection.(3)Based on the direct dynamic method,the nonlinear dynamic analysis of the structure is carried out,and the key columns of the assembled frame structure are destroyed by applying blasting load,and the damage situation is compared with that of the cast-in-place frame structure.The continuous collapse process of frame structure under different key column damage conditions is analyzed,and the displacement and velocity time-history curves of key points of the structure,the plastic deformation of the structure and the stress distribution of steel bars are obtained.The results show that,after the key columns were destroyed,the prefabricated frame structure collapsed continuously in a short time,and the main plastic strain and large reinforcement stress of the structure appeared near the beam-column joints of precast columns,and its anti-progressive collapse ability was slightly stronger than that of cast-in-place frame structure.(4)The nonlinear static analysis is carried out by using the Pushdown analysis method,and the increasing gravity load is applied to the structure to make the structure reach the continuous collapse state.By comparing the load coefficients of assembled frame structure and cast-in-place frame structure,the bearing capacity of the two structural forms is analyzed.The results show that,in the case of column and corner column failure in the structure,it can be seen from the relative bearing capacity-displacement curve that both structures have sufficient bearing capacity.Compared with the failure of the central column,the bearing capacity of the remaining structure is weaker when the corner column fails.In view of the assembled frame structure,the numerical analysis of different splicing modes of steel plates at its connection nodes is carried out.When the central column and corner column fail,the bearing capacity of the structure connected by splicing modes of steel plates arranged horizontally and vertically is equivalent.Figure [85] table [3] reference [62]... |
PDF Full Text Request