Numerical Modeling Theory Of The Hybrid Structure And Its Application In Earthquake Engineering

Hybrid structure composed of two different structures, is an excellent seismic structure, which is increasingly used in modern high rise and super high rise buildings. Many researches can not be carried out by physical test, because the hybrid structure is difficult to be experimented in laboratory. Therefore, it is significant to investigate the numerical modeling theoy of the hybrid structure. It is beneficial to improve the state-of-the-art of the hybrid structure. This paper, taking the SRC frame-RC tube as an example, systematically investigates the numerical modeling theory of the hybrid structure. Based on the proposed modeling methodology, the damage evolution law of the SRC frame- RC tube hybrid structure is researched, and the main contents are as follows:1. Based on the test results of the SRC column and RC shear wall under the different loading protocols, the performance deterioration of the structural members was observed in the experiment and the load-displacement hysteretic curves were obtained. The strength and stiffness deterioration were analyzed based on the tested hysteretic loops. In order to theoretically describe strength and stiffness deterioration, deterioration index is proposed by fitting with experimental data. By comparing the testing results with calculating results for hysteretic curve, energy dissipation ratio as well as viscous damping coefficient, the applicability and accuracy of the proposed model was verified. The calculating results compared well with the testing results, indicating that the proposed model is capable of representing the material nonlinearity of the structure under cyclic load.2. The nonlinear fracture mechanics (NLFM) method was employed to investigate the interfacial behavior between embedded steel and concrete for SRC composite structural members. Considering the stress equilibrium, the interfacial governing differential equations were derived based on some basic assumptions. By introducing 5 different bond stress-slip constitutive models, the closed-form solutions for the distribution of bond stress, relative slip and steel stress are obtained and the anchorange force between embedded steel and concrete can be calculated accordingly. The effective anchorge length for SRC composite structure was proposed on the basis of the analytical results. Based on the experiments of 12 simply supported SRC composite beams, the distribution of bond stress and relative slip between steel and concrete was obtained. By analyzing the influence of the main parameters on interfacial bond-slip behaviors, the occurrence and evolution of bond softening as well as the relationship between local bond strength and its influential parameters was made clear mechanically. In the light of the test results, the regressive formulas of local bond strength were established and the constitutive model of the bond stress versus slip atloading end was proposed. 3. A new finite element for nonlinear analysis of the SRC beam-column is presented, which explicitly accounts for the bond-slip effect between the steel and the concrete. The element is established based on the small deformation assumption and the shear and torsion effect is neglected. The non-linear hysteretic behavior of the element derives from the constitutive relations of the concrete, steel and bond interface fibers into which each section is divided. The element formulation is flexibility-based and relies on force interpolation functions that strictly satisfy the equilibrium of bending moments and axial force along the element. The proposed element shows computationally stable and robust numerical behavior, while being able to describe very well the hysteretic behavior of the SRC beam-cloumn under the imposed complex loading histories.4. The damage of the SRC frame-RC tube hybrid structure storey under cyclic load was investigated. Based on the proposed beam-column element for SRC member and the shear wall element, the numerical modeling of the SRC frame-RC shear wall hybrid structure storey was realized, and the influence pamaremters are column-beam strength ratio and span-depth ratio of the coupling beam. Based on the computing results, the failure mode of the storey, dissipation capacity and damage characteristics was analyzed. After that the relationship between storey and structural members was estabilished.5. The damage of the SRC frame-RC tube hybrid structure under cyclic load was investigated. Based on the proposed beam-column element for SRC member and the shear wall element, the numerical modeling of the SRC frame-RC shear wall hybrid structure was realized. The computing of the structure damage is according to the frequency variation. The effect of the storey damage on the structure was researched, and case of the low damage, moderate damage and high damage was considered. After that, parameter study was carried out and the relationship between storey and structure is estabilished.