Research On Seismic Damage Assessment Method Of Highrise Rc Frame-Core Wall Structure

As the development of the economic and the quicker pace of the urbanization, the proportion of the high-rise buildings has become larger and larger. Therefore the damage evaluation for high-rise buildings after the earthquakes becomes even more important. This paper is focus on the study of seismic damage evaluation methods for high-rise reinforced concrete structure on different levels of member scale, storey scale and overall structure scale.1. In this paper, a method of seismic damage fuzzy evaluation for high-rise buildings is proposed, based on the research on wavelet packets of acceleration data measured in storeys. Considering the sensitive of Wavelet Transform to the changes in signals of structural responses, in the proposed method, the signals of acceleration, which are measured in storeys, are processed by wavelet decomposition to obtain the rate indicators of energy changes in frequency band. After that, the indicators are partitioned by the relation between the rate of energy changes and the real damage, to obtain the membership degree of fuzzy evaluation in different damage states. Then the storeys and overall structure are graded on damage by fuzzy comprehensive evaluation method. Using the proposed method, the damage evaluation is applied on the shaking table model test for the practical project-1. The proposed method provides good agreement with the test results. The parameters needed in the proposed method are obtained through the model test.2. Because of the uncertainty in the non-linear constitutive model of materials, which is used in calculation, the results of finite-element analysis of structure under strong earthquakes are probably rather different from the reality. Best on correcting the storey displacements, a damage evaluation method for high-rise frame-core tube structures is proposed in this paper. The storey displacements calculated by finite element analysis are corrected by the measured displacements. The maximum corrected inner-storey displacement is applied on the equivalent linear-stiffness model of sub-structure of storey. Then by calculating the stiffness reduction, the results of damage evaluation on member scale are obtained. The results on overall scale are obtained by weighted combination of the results on member scale. The research shows that the correction coefficient of displacement changes correspondingly with different plastic development state of the structure. A correction coefficient with the rate of shear-weight ratio as variable shows rather reasonable relationship with the plastic development.3. The methods of damage fuzzy evaluation based on wavelet packet energy and damage evaluation based on displacement correction are both depend on the information of displacements, and also both on the storey scale. In this paper, the universality of the both methods are verified through the modeling and shaking table test of practical project-2. On the basis of the damage evaluation methods, which are based on displacement correction, when applying the procedures of fuzzy evaluation based on wavelet packet energy and the displacement correction expression with the rate of shear-weight ratio as variable, in which the calculating parameters are obtained from the practical project-1, to the practical project-2, the displacement correction coefficients obtained by finite element method are acceptable compared with the coefficients measured in the table shaking test. Therefore even without the monitoring system for displacement measurement, the displacement correction coefficient can be obtained by finite element method and then used in damage evaluation.4. The two methods mentioned above are both on storey scale. However, the same storey damage can be related to different types of member damage; therefore solely evaluation on storey scale is not enough. To solve this problem, in this paper, a damage evaluation method on member scale, which is based on the coefficient of damage distribution, is proposed, through the finite element analysis on the damage distribution of all kinds of memebers. In the proposed method, the storey damage coefficients of different members are obtained by each relevant calculating method, according to their own characteristics of damage. Then the pattern of damage distribution after earthquakes is studied from the energy point of view. Therefore the information of damage distribution of different members is obtained quickly by the existed finite element model and the practical seismic motion input. Also the weight coefficients of their own damage are obtained by weighted computation of different kinds of members'total damages, to evaluate the damage of overall structure. The trait of the proposed method is that it can obtain the damage evaluation results on member scale and it is suitable for the structures without deformation monitoring system. The comparison between the test and the results obtained by numerical modeling of the practical project-1 shows that the proposed method is effective.Three methods of seismic damage evaluation for high-rise frame-core tube structure are proposed, to evaluate the damage of structure on different aspects and scales. The proposed methods are verified to be effective. In practical engineering, the proposed methods can be chosen depending on the actual situations, and also the results obtained by three methods can be verified by each other.