Study On Seismic Response Of Reinforcement Masonry Structure

environmental protection, reinforcement masonry structure is widely used in tall building in developed countries such as the United States, Europe and Japan. The theory system and experimental statistics of the study in this field are not sufficient because of the relatively late starts. Therefore, the study on it is still the focus in the field of engineering structure seismic study. The paper focuses on a 10-stories reinforcement masonry structure, which is in scale of 1/4, and the core casting ratio is 19%, through the anti-seismic test on shaking table as well as elastic and plastic numerical simulation analysis, the following achievement are obtained:1. The test constructs the reinforcement masonry structure model according to the similarity between the model and prototype, and the General Similitude Law as well. The detailing of this model complies with the fortification intensity of VII, but 3 stories beyond the seismic code. Three earthquake records of Northridge,EL Centro-1,EL Centro-2 are selected to input onto the model, corresponding to the different site conditions ranging from hard to soft respectively, applying the records PGA between 0.06g~0.32g, which are equivalent with the frequent intensity, basic intensity and rare intensity. The test inputs 25 records from the direction of X, Y, and X&Y simultaneous, gets massive records of seismic response, analyzes the seismic response, deformation and seismic damage on the model. The typical statistics were organized and analyzed, which set a solid foundation for the seismic evaluation on the building structure.2. Basing on the output records on X-direction and Y-direction, the paper analyzed dominant frequency, accelaration response of model structure, vibration mode, displacement and strain. The expression of regression curve was concluded by analyzing the relation between table input PGA and the dominant frequency of top output. Through comparing the top acceleration amplification factors of X-direction and Y-direction, the average value is 2.7 and 2.0 for X-direction and Y-direction respectively, which is 35% higher than the other. The main reason is that the dominant frequency of X-direction is lower than that of Y-direction, which is similar to the frequency range, therefore, more resonance takes place. The first three vibration modes on both directions are showed in the paper. The paper also analyzes the time history of the relative displacement and the strain under different PGA.3. The experiments are conducted according to the loading plan, and cracked condition is observed carefully. The focuses are as follows: cracked location, crack direction, crack width, the damage behavior of the structure and the element. The paper analyzes the damage condition of the model structure and describes the damage mechanism. By analyzing the experimental statistics, the rule of during and after input predominant frequencies is concluded, and the vibration mode of the structure and structure behavior under different input are analyzed. The appearances in the experiments show that the model meets the requirements as"Perfect subjected to minor earthquake; the maintenance subjected to moderate earthquake; no collapse subjected to unexpected rare earthquake."4. The numerical analyzing model is constructed as X-direction for wall type frame and Y-direction for shear wall. Considering the elements of shear wall, column and beam, fiber model are applied to general structural elements. Three parameter park model is based while considering the hysteretic rule of the structural elements. The hysteretic rule takes stiffness degradation, strength deterioration and slip into account, which values are referred relative reference. The damage potential system is on the basis of damage index proposed by Park&Ang.5. Using the IDARC5.5 to conduct analysis on the elastic-plastic seismic response of model structure, the paper contrasts the numerical results to experiment findings after studying the model parameter and the damage condition on both X and Y direction. The paper also discusses the story shear force, displacement, acceleration responses under various PGA of fortification intensity of VII. Meanwhile, the values of story shear force are contrast via experimental results, numerical results and calculation results by code method. Moreover, the change of natural frequency and damage index are researched. Through analyzing, seismic response condition and damage extent are concluded under different input. The achievements indicate that reinforcement masonry structure with moderate core casting (19%) meets the requirements of fortification intensity of VII to resist earthquake effectively. The research conclusion has significant value to modify the seismic design code of reinforcement concrete masonry structure.