Progressive Collapse Analysis Of Unbonded Prestressed Fabricated Frame Based On Removing Column Method

Prestressed fabricated frame structure node connection performance is the guarantee of the green building, industrial architectural design and construction of the key technologies. Prestressed fabricated structure in our country is still in research stage currently, prefabricated split method relative lag, poor reliability for the frame structure fabricated connecting node, node connection research lags behind in terms of theory. On the other hand, as a result of the UK Ronan Point apartment (22 layers of fabricated reinforced concrete panel structure) and the World Trade Center towers collapse successive catastrophic accident, anti-progressive collapse performance of the structure is more and more attention. Therefore, the research of the prestressed fabricated connection node performance and the overall structure anti-progressive collapse performance is of great significance. In this paper, using the finite element the nodes of unbonded fabricated frame structure is simulated, and the overall structure of the anti-progressive collapse performance makes a preliminary analysis. The main contents and results are as follows:(1) Combined with special structure of unbonded prestressed fabricated node connections, based on the OpenSees finite element software, using zero length unit to simulate the unbonded prestressed precast connection of nodes firstly, selecting suitable material constitutive and element types to establish finite element model, The calculated and experimental results of the literature [25]were compared to verify the accuracy of node simulation, it is preferable to restore the node hysteretic performance.(2) Under the current codes to design a six-story unbonded prestressed fabricated frame structure and comparison of cast-in-place frame structure, combination of node modeling method, finite element analysis model is established for a cross, based on a reasonable setting of component failure criterion, using OOM software algorithm of literature [29], by modifying the Tcl script files to add the corresponding material constitutive and unit, as well as the automatic calculation of the structure rayleigh damping, thus the progressive collapse calculations of unbonded prestressed fabricated concrete structure as well as cast-in-place frame structure have been completed, and a simulation of the dynamic structure of the progressive collapse process have been achieved.(3) Through the analysis of the internal force time history changes of the key component after removing, as well as the failure point displacement time history, the analysis of anti-progressive collapse reserves of unbonded prestressed fabricated frame structure have been accomplished. The results show that:unbonded prestressed fabricated frame structure after removing column catenary effect significantly; in the same column section and reinforcement, beams under bending capacity of the same, due to the additional unbonded prestressed tension makes the unbonded prestressed fabricated frame structure anti-progressive collapse reserves is higher than the cast-in-place frame structure.