Evaluation Method Of Seismic Failure For High-rise Buildings Based On Overall And Member Damage Indices

Quantitative analysis of failure evolution process is one of the critical steps to achieve performance based seismic design of high-rise buildings. In order to describe the failure mechanism of high-rise buildings more efficiently, the quantitative analysis of failure evolution process was studied through overall stability failure process of structures and damage accumulation. Quantitative description of failure evolution process of high-rise buildings was realized, which was based on the overall stability failure index and the damage index. The main contents of the thesis were as follows:(1) Overall stability analysis of structures. Approximate equivalent lateral stiffness of high-rise buildings was given by deformation analysis and the deformation patterns were discussed. In addition, gravity second-order effects of high-rise buildings were studied; and the influence of stiffness-weight ratio was obtained by analysis of overall stability of the high-rise buildings.(2) Research on the identification method of structural failure based on overall stability. Instantaneous equivalent stiffness-weight ratio was defined by equilibrium analysis of overall stability. The relationship of non-linear structural responses and instantaneous equivalent stiffness-weight ratio was deduced, and the identification method of structural failure was given based on degenerate of instantaneous equivalent stiffness-weight ratio. Then the relationship between failure indices and failure states was determined. And the identification method was verified by experimental tests and elastic-plastic time-history numerical simulations of high-rise buildings.(3) Research on failure behavior of shear walls based on material damage. The major parameters affecting failure states of shear walls, including depth-width ratio and axial compression ratio, were obtained by discussion of cyclic load test results and numerical simulation of failure evolution process of shear walls with different design parameters. According to the characteristics of material damage, the failure modes of RC shear walls were classified as shear-type and bending-type. The damage indices, reflecting damage of shear wall components, were achieved by damage information fusion based on material damage mechanics. Also, the identification methods of damage indices, corresponding to different failure modes of shear walls in failure evolution processes, were described.(4) Research on failure behavior of RC coupling beams based on material damage. The major parameters affecting failure states of RC coupling beams under rare earthquakes, including shear span ratio, shear compression ratio and stirrup characteristic value, were determined. According to the feature of material damage, the failure modes of RC coupling beams were classified as shear-type, bending-type and bending-shear type. The damage indices, reflecting damage of coupling beam components, were achieved by damage information fusion based on material damage mechanics. Also, the identification methods of damage indices, corresponding to different failure modes of RC coupling beams, ware described.(5) Research on failure behavior of RC columns and frame beams based on material damage. The major parameters affecting failure states of RC columns and frame beams were proposed by discussion of cyclic load test results of RC columns and frame beams with different design parameters and numerical simulation of failure evolution processes. The failure modes of RC columns and frames beams were classified. The damage indices, reflecting damage of columns and beams components, were achieved by damage information fusion based on material damage mechanics. The identification methods of damage indices were described for different failure modes of RC columns and frame beams.(6) Research on failure behavior of high-rise buildings based on damage. The damage evolution transfer coefficients were obtained in the processes of damage evolution from material degradation to structural failure, which were based on the damage models in components and were justified by the types of the components, the importance of the components, the damage degrees and locations of the components. In this way, the damage evaluation was realized, which can transfer from material failure to structural failure. Finally, the engineering practice verified that the method was feasible.