Applied Mechanics and Materials Vols. 256-259

Abstract: Structural design of large aperture mirror is one of the key technologies for space telescope development. To meet the requirements of high stiffness, strength and thermal dimensional stability, some factors such as support scheme, materials selection, lightweight design and flexible support design were taken into account. The three supports location of the mirror was determined according to the modal analytical solution. By adjusting the parameters of flexure hinge, influences of gravity, assembly stress and thermal stress on the mirror were reduced obviously. Finite element analysis (FEA) results indicate that the surface accuracy reach to rms10.2nm and 10.8nm under the gravity along optical axis direction and 5°C uniform temperature rise respectively, the fundamental frequency of the mirror component is 268Hz. Dynamics test shows that the first order natural frequency is 256Hz, which shows an error less than 5% compared to FEA results.

Abstract: Reinforced protective layer to ensure the durability of reinforced concrete structures important tectonic structures plays a vital role. Reinforced concrete reinforced the lack of a protective layer will affect the durability of the components, in serious cases, the member failure early. Meticulous construction, requires not only the structure of acceptable quality, also require durability is better. This paper tries to force mechanism of reinforced concrete together, combined with years of construction practice, to talk about the importance of control in the construction of reinforced protective layer.

Abstract: Compression performance of pultruded GFRP (Glass Fiber Reinforced Plastics) can be improved by confined CFRP (Carbon Fiber Reinforced Plastics) sheet, but it was affected by some factors. Two groups GFRP short pipe specimens of different outer diameter (104mm and 76mm) were axial compressed. The failure modes of longitudinal splitting and compressive strength failure for the GFRP pipes and those confined by CFRP sheet respectively were comparatively analyzed. Analysis on the influence to the compressive performance of GFRP short pipes confined by CFRP sheet was made from mechanical and geometrical parameters of the CFRP and GFRP in numerical methods. The laws of improvement of compression performance of CFRP sheet confined GFRP short pipe were recognized.

Abstract: Site-built reinforcing rib composite wall is a kind of composite wall composed of reinforced concrete rib columns, rib beams and filling masonry. This paper mainly introduces the failure process and failure mechanism of this kind of composite wall under low cyclic loading. The wall has a good seismic performance and can be suitable for rural building structure.

Abstract: According to the fact that softening temperature of organic epoxy adhesive is too low to meet fire, an inorganic adhesive whose strength at 600°C is not lower than that at normal room temperature, is developed to bond Carbon Fiber Sheet (CFS) in order to strengthen reinforced concrete beams. To understand all-round mechanical performance of RC beams strengthened by CFS bonded by an inorganic adhesive after fire, on the base of experimental research, Conjugate Beam Method is used to analyze the whole mechanical process from loading to failure. The test and analysis results show that, for RC slabs strengthened by CFS bonding with the inorganic adhesive, maximum stress of CFS decreases with small amplitude compared with that before fire, and the strength of the sheet can be utilized to a great extent, even if temperature (about 300°C~470°C) an inorganic adhesive experienced outclasses softening temperatures of ordinary organic epoxy adhesives. Beams strengthened by CFS bonded with inorganic adhesive perform good fire behavior.

Abstract: Built in Chinese specific historical period, most western-style historical buildings have the western pattern and Chinese structural type. In many years of existence, they mostly face a grave situation because of the damages and risks in structural safety. To better protect them, an in-depth understanding is required. Taking Zizhulin Church in Tianjin as the case, it adopted the brick-timber structure, with local technologies and concepts applied in this church to achieve the western pattern. The well-planned layout and facade, the materials, as well as the constructional details are analysed, which are favorable for the vibration resistance. These analyses can provide reference for protection and repair of other similar western-style historical buildings.

Abstract: The ability to structure durability refers to the concrete structure in the natural environment, the role of the environment and material internal factors in the design requirements of the target period do not need to spend a lot of money reinforcement processing to maintain its safety, function and appearance requirements. . With the continuous development and transformation of China’s urban scale, a large number of existing structures by the post-test, further reinforcement of the design and reconstruction of this paper, the actual project to detect and evaluate the durability of reinforced concrete structures, reinforcement of existing buildings in the future and the transformation of the former’s identification with a certain reference value.

Abstract: The selection and arrangement structure is the starting point of glass curtain wall building structure design. On the basis of the structural partition types, the paper discusses the various structural system which be used in engineering in detail. Especially introduces the reasonable layout of the beam system, truss system, framework, arch structure, space truss system, suspension system and so on. Finally, the basic principles and key points of the connection glass curtain wall system structure are also discussed in the paper.

Abstract: With the increase of the mining depth, the surrounding rock of roadways shows the characteristics of soft rock that the stress increase, poor rock cementation, broken loose, a significant expansion, creep deformation, etc. Deep roadways mainly use the combination of active and passive supporting method, U-type shed is widely used in the roadway support and becomes gradually the main supporting form. This paper studies mechanical properties of different arched U- type sheds, then compares the stress distribution and the displacement change. According to the result of simulation and optimization, it is seen that the deformation trend is regular with the angle change, and when θ=30°, the U- type shed is better in the roadway support. The conclusion can provide some theoretical guidance for the deep or soft rock roadway support.

Abstract: The study was carried out under El-Centro wave with SAP2000, and the appraisal results on their anti-failure performances were presented under strong earthquake action based on theplastic-hinge theory. In the analyses, the geometric and material nonlinear effects were considered simultaneously. The plastic development level of the rods, the deformed shape and the failure type and the ductility were estimated by plastic hinge principle. The results show that the failure model of the structure under the earthquake wave action is the complicated combination of strength failure and elasto-plastic dynamic local buckling in deferent areas; When the structure reached its failure critical limit, only 14% of the rods enter into their plastic stage and the development of the plastic hinges is not sufficient; Its critical failure peak acceleration of EL earthquake wave when applied in the combination of three directions is 969gal, which is equivalent 2.425 times to the official seismic fortification level of 8 degree (major earthquake, 0.4g) and it can be served as earthquake victims shelter in the area of 8 degree seismic fortification; Its displacement ductility coefficient is 2.88, which shows the structure owns some energy dissipation capacity.