Study On Seismic Behavior And Seismic Design Method Of R.C.Structure Of Large--Scale Thermal Power Plants

The damage caused by earthquakes at home and abroad indicates that R.C. structures will suffer failure and even collapse under medium or strong earthquakes. The main buildings in large-scale thermal power plants are a sort of important lifeline engineering, and should have better seismic behavior. Investigate on seismic behaviors of this kind of structures is of importance on practical and theoretical values. This study is to provide the experimental data and theoretical approach of this type structure system and assess earthquake-resistant behavior and damage characteristics of this kind of system.A 1/7-scale model of three-bay, three-span frame-bent R.C. structure is the first and the largest size in the same testing field in China by now. Following studies are chiefly conducted in this chapter: the mechanism behavior of the structure under horizontal earthquake load, including the characteristics of seismic force, the deformed performance, yielding sequence, energy dissipation capacity etc.; the changing rule of the dynamic characteristics and the stiff degrading in different experimental stages; the location of the weak stories and the seismic capacity of the structure. Damage mechanism and weak positions of the structure under earthquake are considered.In the modal analyses, the frequency analogical ratio between scale models with less ballast and their prototype is derived. Based on the analogical ratio, the natural frequency of prototype is impetrated.Based on the pseudo-static experimental results of nine specimens 1/5-scale specimens and failure characteristic in the structural test, the damage mechanism and the failure of abnormal joints under the shear force is analyzed. The paper discusses the possible affections of stirrup ratio, the changes of beam or column sections and initial eccentricity on carrying capacity of abnormal joints. According to experimental data, the formula for calculation of the shear-bearing capacity of abnormal joints is given.Analysis of prototype with frame-bent in the longitudinal direction and frame-shear wall in the transverse direction under the earthquake with peak acceleration 50gal. is conducted.. The followingsubjects are concerned: the dynamic properties, the torsional effect on the structure, split lever influence on the distribution of the shear forces in the columns, the mechanic of the frame corporation with the bent. The simplified calculation method is given.In connection with the characteristics of prototypes and elasto-plastic analysis, the cross-sectional discrete finite element method is used to establish a computational space model. The nonlinear time-history seismic analyses are carried out by using ANSYS, FEA software. It mainly deals with inelastic response of prototypes, torsional response characteristics of building, the behavior of the frame corporation with the bent under strong earthquake, etc...A simplified calculated method about determination of the weak story is presented. Some helpful conclusions were made.Based on the experimental results and theories research, the author put forward some valuable conclusions of this new type of frame-bent structures: (1) The initial force calculation method considering the lateral torsional coupled; (2) The design and construction method of the high-strength concrete frame-bent columns under the high axial compression ratio; (3) The construction method of the abnormal joints.By the pseudo-dynamic test and modal analysis of the frame-bent structure, the paper discussed the seismic behavior, calculation method of initial force, simplified design method and structural features of this type of structure. The author's research can be used as reference to establish the relative codes.