Applied Mechanics and Materials Vols. 204-208

Abstract: Energy dissipation mechanism is very important for the structural collapse-resistant performance under strong earthquakes. Two reinforced concrete (RC) frame-shear-wall structures with different span-depth ratios in coupling beams were designed according to current Chinese seismic design code and then analyzed by nonlinear time-history analysis method under a serial of strong earthquake records. Based on the analysis results, energy dissipation mechanism and collapse-resistant performance of the two structures under strong earthquakes are studied. And the “strong wall limb-weak coupling beam” mechanism, which is achieved in the structure with larger span-depth ratio in coupling beams, is proposed to serve as the reasonable energy dissipation mechanism for RC frame-shear-wall structure. The damage of wall limb is controlled effectively under this energy dissipation mechanism, which leads to good collapse-resistant performance.

Abstract: Multi-story Masonry Building with R. C. Frames on Ground Floor (Framed-Ground Floor Structure for short) which has serious seismic damage and high collapsed rate, is the unreasonable structure system. However, the structure system not be abolished for economic reason. Collapse types of that are divided into collapse of ground floor, collapse of transition layer, global collapse. And seismic damage is also serious for frame column and shear wall. Experiences are obtained from above seismic damage, and the following aspects should be taken into account in the future. 1. The shear wall can be increased to improve stiffness of weak layer. And designer should try to arrange the walls equably. 2. In order to avoid stiffness mutation, stiffness ratio between ground frame and transition layer can be adjusted. 3. Collapse resistant design of Framed-Ground Floor Structures should be emphasized.

Abstract: This paper describes the multilayer and high-rise structure of the precast prestressed shear wall, we made one shape T shape and linked limb shear wall specimens as the objects, we also made comparision with cast-in-place shear wall, the specimens were tested under high frequency and reciprocating horizontal load. And it is analyzed in yield load, bearing capacity, stiffness degradation, energy dissipation as well as ductility conditions by test data. The result shows that Wall’s damage concentrated in roots near the connection, where is the weak area of the precast prestressed concrete straight shear wall, and the wall show characteristic bending failure.

Abstract: With the development of the control research, intelligent control has become one of the most popular research topics worldwide. The traditional method of Numerical simulation on control theories are realized by the programs in MATLAB, which is based on numbers of assumptions and simplification. However, it is difficult to ensure that the seismic response of the structure is always in linear elastic state during the process of hazard evolution under strong earthquake so that certain errors during such simulation are inevitable. In order to solve this problem, a numerical method of the realization of semi-active control in commercial finite element software ABAQUS is proposed in this paper. One of the main advantages of this method is that the structural plastic response can be taken into account. In this paper, the seismic response of a bridge with three-span continuous girder is numerically studied, and the semi-active control is successfully realized in ABAQUS. The proposed method can be used to carry out the refined simulation of the seismic response of the structures with semi-active control set. The highlight of this paper is to provide an effective approach for the research of intelligent control.

Abstract: Based on the soil-structure interaction theory and finite element method, this paper analysis the seismic response of pile-soil interaction system in super high-rise building. This paper established a structure- pile-soil finite element mole of a super high-rise building in Tianjin area and analysis the dynamic response of superstructure and the internal force and displacement of the pile considering the influence of pile’s slenderness ratio. The results show that, the displacement and acceleration of the top of interaction model are increased compared with the fixed base model. Under seismic excitation, the peak displacement and the peak acceleration of pile top are larger than the pile bottom. As the pile’s slenderness ratio is larger, the inter force and displacement seismic response of the pile is larger and the variation of peak is bigger along the pile.

Abstract: Reinforcement concrete (R/C) structure is constructed and developed very rapidly in recent 30 years with the economic increasing not only in metropolitan cities but also in wide rural areas of China. It’s famous for its’ easy construction and high load bearing capacity. But in recent large earthquakes, more and more different type of severe damages about R/C structures have been observed due to either unreasonable design or extra-high ground shaking intensity exceeding the design level mostly. In the field investigation for the 2010 Yushu Ms7.1 earthquake of China, six RC frame buildings, were investigated and tested by means of the ambient vibration test method. Both of the test results of the natural frequency for each building as well as its’ damage pattern were described and briefly analyzed in this paper. The investigation results provide reference data for nonlinear numerical analysis and retrofitting of RC frame building structures.

Abstract: This article mainly aims at the frame structure seismic identification and reinforcement, and example analyzed a middle school building structure of the framework aseismatic appraisal and reinforcement.

Abstract: With the SMA (Shape Memory Alloy) banner model, the effect of pre-stressing and displacement, stiffness and length to the energy dissipation ratio is studied. The two equations, which are of pre-stressing and displacement to the energy dissipation ratio are proposed. The method are put forward to confirm the stiffness and length of SMA . Based on the above analysis, a new pull-press SMA damper is designed. The simulation analysis on seismic response of five-floor frame with SMA damper shows that the displacement and acceleration of the top floor are reduced by 50﹪at least. It verifies that this kind of SMA damper can availably suppress the seismic response of structure.

Abstract: In this research, a reduced scale model of the composite high-rise building with steel reinforced concrete column, steel beam and reinforced concrete core tube was designed and tested by using the shake table test technology. The acceleration and displacement of the model were measured during the tests. The cracking pattern and failure mechanism were illustrated. Above the shake table test, the finite element analysis of the test mode was carried out. The main effort of the numerical analysis was focused on the selection of the nonlinear models. Based on the experiment results and the strategy of considering nonlinear property of the beam-column joint and the short beam of the concrete core wall were proposed. It is proved that the proposed strategy is effective and economical for seismic behavior assessment of such composite high-rise building structure system.

Abstract: This study concentrates on investigating the 28d strength of fresh concrete after the occurrence of a simulated earthquake at magnitude of 9. The experiment has been carried out through the simulated earthquake that was generated by a high-performance vibrating platform with a size of 6m×6m, provided by the Nuclear Power Institute of China. There were 14 kinds the fresh concrete (C30 and C50) with seven ages (6 hours, 12 hours, 24 hours, 48 hours, 72 hours, 168 hours, 336 hours) acted by a types of ground acceleration (0.50g). The modified El centro was used to take the recordings of the time series of parameters. The results show that the strength of the fresh concrete undergoing the simulated earthquake can be well recovered after 28 days. It is nearly the same to the concrete which not vibrated by the earthquake in the same curing condition. Also the effect mechanism of the earthquake upon the fresh concrete had been analyzed.