Equivalent Static Design Method Of Parallel Double-Run Plate Stair With Frame Structure And Seismic Performance Study Of The New Model Of Semi-Rigid Joints

In the2008Wenchuan earthquake, the buildings of frame structure showed their outstanding seismic performance. However, among those kinds of structure systems which the main structure damage is light, the damage of stair components is the most grave. The main reason is the bracing effect of the stair boards leads to the enlarging of partial rigidity of stairway. As the result, for absorbing large energy of earthquake, the stairways as the first seismic fortification line are destroyed earlier than the bodies. Currently, there’s little stair components designs considered on involving the calculation of whole structure and the earthquake action. And facts proved that this calculating method of stair components design is relatively insecurity.For the above reasons, in this thesis, it proposes a model of a simple regular multi-frame structure through the use of SAP2000, the international software of structure analysis, the model of stair components with double-run plate, which involving the seismic calculation of the whole structure analyzed by response spectrum and elastic time history. According to the true stress to calculate the reinforcement, And compared with traditional hand calculation method and calculational results of the small structure software (for example the Lizheng structure software), Summed up the reinforcement of amplification factor based on present algorithm under different seismic fortification intensity of stair components. Equivalent static design method is proposed. At the same time, the analysis results show that in high seismic fortification the stair components need too much area of reinforcement that unable to collocate reinforced bars. In order to solve this problem, Put forward the new structure of semi-rigid node measures, weakened the connection of stairway beams and stairway flight, similar to use the processing method of shear bolts. This processing method was verified by the finite element analysis results that the internal force and reinforcement of staircase components have a different degree of reduced, obtaining good effect, has a certain feasibility.Using SAP2000do elastoplastic time history analysis under infrequent seismic by sequential order of plastic hinge appears simple make a discussion of the structure deformation law and yielding mechanism. Compared the calculation results of the rigid and semi-rigid node model, which the latter improves seismic behavior and energy dissipation of later part or structure, make the staircase as the second measure to resist the earthquake and so protect the safe passage, and the peak force of stair components under infrequent seismic also reduced a lot.