Advanced Materials Research Vols. 639-640

Abstract: Passive devices for vibration control are widely adopted in earthquake engineering for mitigation of seismic effects obtaining an efficient, robust and not expensive structural protection. They are largely used in the seismic protection of industrial machines, technical equipment, buildings, bridges and others more as reliable and affordable solutions. Moreover their performances are extremely sensitive to their dynamic mechanical behavior; a reliable identification of their mechanical behavior is therefore of key importance, despite the current lack of accurate and simple standard procedures to identify parameters and models for those devices. In this work, a new procedure for the dynamic identification of passive devices is described, through standard laboratory dynamic tests and the use of evolutionary algorithms. This procedure allows to find proper mechanical law and parameters to use for an accurate structural analysis and earthquake-resistant structure design. The procedure uses standard pre-qualification and quality-control tests, and consists in the minimization of the integral measure of the difference between mathematic and experimental applied force to the device under an imposed displacement time history. Due to the amount of corruption source of the experimental data and to the deep non linear nature of the problem, the use of evolutive algorithms is the main way to solve hard numerical task in an efficient way. The proposed procedure is applicable to a wide range of mathematical expressions because of its inherent stability and low computational cost, and allows comparing different mechanical laws by ranking their agreement with experimental data. Results are obtained for different experimentally tested devices, that are viscous dampers and seismic isolators, and are reported in order to demonstrate the efficiency of the proposed strategy.

Abstract: More and more attention has been paid on the development and utilization of new energy sources, as the global energy crisis escalated. Combined with the concept of wind energy generation and High-raise steel structure, a new type of building structure is proposed integrating high-rise steel structure with vertical axis wind turbines. Static analysis under equivalent wind load of seven different wind pressures were carried out on two models, one with wind turbines and the other one without. The feasibility of this new structure was verified preliminarily by comparing analysis results.

Abstract: From the analysis of several typical phenomenon of “false low carbon”, the only way of achieving low carbon and sustainable development for the housing industry with industrialization and integration has been put forward, so as to clear the basic connotation of the integrated manufacturing house in factory, and the integrated housing development progress and the trend have been pointed out in this paper, too. Then based on the analysis of characteristics of the integrated light steel housing structure and facing its development obstacles, some specific solutions have been put forward in the end.

Abstract: Static tests were conducted on integral structure of light steel temporary buildings under wind load. The mechanical behavior and the deformation performance of the structure were investigated. A kind of new system of load distribution beams was applied, which imposed the horizontal loads and simulated the uniformly distributed wind load. The load-displacement curves of the columns were obtained. And the strains of the columns and the wall panels were obtained also. The performances of the light steel temporary building are summarized and discussed.

Abstract: The recycled aggregate is dealt with in three ways, the first way is to keep the recycled aggregate intact; the second way is to wrap the recycled aggregate in cement slurry of Water-cement ratio 0.55 for 30 minutes, and then place it at room temperature for 7 days; the third way is to immerse the recycled aggregate in water for 24 hours. Three kinds of different recycled aggregate is separately used for mixing of recycled concrete. The strength and slump of recycled concrete with different recycled coarse aggregate contents are tested. Experiments show that the recycled concrete produced by using the recycled aggregate immersed in water and selecting a suitable mix has the higher strength and slump，which can be industrialized. And then, the recycled concrete with 40% recycled coarse aggregate contents is used in the steel-reinforced recycled concrete beams, which are tested, the failure process of steel-reinforced recycled concrete beams,section strains and maximum load are acquired. Research shows the steel-reinforced recycled concrete beams conform to plane hypothesis before the load reachs 80% the limit load, the flexural bearing capacity of the steel-reinforced recycled concrete beams can meet the demand of Technichal Specification of Steel-Reinforced Concrete Structures. The use of recycled concrete in the composite structures is proposed.

Abstract: Based on the structural features of net shell and prestressed arch structures, prestressed arch-supported net shell structures have been developed as a new large space structural system. Dynamical performances and stability of a real prestressed arch-supported net shell structure are analyzed in this paper by using ANSYS. The structure vibration frequency and natural conditions are extracted using dynamical modal analysis method. Because of the bigger ratio between the span and the thickness and smaller critical load values, significant stress advanced phenomenon of some truss bars will appear in the influence of construction when prestress cables are introduced to the space structures (especially for the combination of truss arch and net shell). These effects will make link nodes keep certain stress. Literature survey shows that the research on how the residual stress influences the stability of the structure is very still insufficient. Therefore, the overall stability analysis of the prestressed arch-supported net shell structure is very necessary. The result of research shows that the vibration frequency of prestressed arch-supported net shell structures is enhanced continually with the stronger overall stiffness. Vibration models are significantly different for diverse different structure forms. Result of this study also shows that the stress makes the buckling ultimate load of prestressed arch-supported net shell structure be improved markedly and the stability of prestressed arch-supported net shell structure be enhanced. As a result, the overall performance of this new hybrid structure system is better and it has a certain application prospect.

Abstract: Base on the traditional assumption, beam-to-column minor axis connections are usually considered either as perfectly rigid or as nominally pinned. In fact, many researches show that beam-to-column minor axis connections are often semi-rigid, and their performance greatly effects the internal force, displacement, and ultimate bearing capacity of the steel frames, which cannot be neglected. Welded joint, one type of beam-to-column minor axis connections, which is widely used in the engineering practice is researched. The finite element method was used to analysis the relationship between the parameter variation and the rotational initial stiffness of the connections. The results can be used as a reference to the designs of steel frames.

Abstract: Common concrete miniature hollow block masonry is the main promotion material in wall materials reform of China. The paper presents the structural design and the calculation process of the tall building wall emphatically. It meets the specification. The design can be used as a reference to similarity engineering.

Abstract: The elastoplastic nonlinear analysis is provided by considering both spatial effect and influence of slab and connecting beam. The seismic internal force distribution is also studied. It shows that compared with the 2D model and traditional 3D coupled shear wall structure, 3D skip-floor staggered shear wall structure has superiority in many respects, such as initial rigidity, uniformity of force, energy dissipation, etc. Therefore, this new structural system has good economic benefits and wide applications.

Abstract: Kiewitt dome structure is commonly used in spatial structures, on which many researches have been carried out. However, few researches focus on irregular dome structure. The mechanical performance of an irregular Kiewitt dome structure, cut by two vertical planes from a semi-sphere dome structure to form two openings supported by beams for architectural gates, is studied. The analysis and comparison of the dome structures with the opening or not, as well as the parametric analysis of section of the supporting beam, are conducted by SAP2000. Finally, nonlinear analysis is done by ANSYS. The results show that the existence of openings decreases the integrity of the structure and the members near the opening need to be strengthened. The stiffness of the arch beam has great effects on the vibration characteristics, the axial force distribution of the members, and the buckling modes of the structure. Proper arch beam section is recommended to meet the requirement of the structure.