Applied Mechanics and Materials Vols. 488-489

Abstract: Foam concrete is a new building energy-saving material, which has the characteristics of light weight, heat insulation and fire prevention. The use of foam concrete slab with grooves cast roof or wall as a template can reduce the amount of the construction process, the cost of project and improve the structural thermal insulation properties. By testing the thermal defects and heat transfer performance of outer insulation and self-insulated wall, and analysis 2 kinds of wall’s heat transfer coefficient, thermal inertia indicators and technical and economic characteristics with Building Heat Transfer Theory, obtain : Foam concrete self thermal insulation wall indoor a hot environment, thermal stability and resistance against external temperature fluctuations is stronger; foam concrete self thermal insulation wall have a good heat transfer performance, and have better marketing prospects.

Abstract: Influences of limestone powder on the hydration progress of cement and the properties of dam concrete were studied in this paper. The results show that, as mineral admixture, limestone powder accelerates the cement early hydration and takes part in this hydration which produces the calcium monocarboaluminate hydrate, but, limestone powder doesnt have the pozzolanic activity. Limestone powder has an adverse impact on the pore system of hardened pastes, especially these pores size range from 3 nm to 107 nm. Fortunately, the pore system will be optimized by using some fly ash instead of part of limestone powder. Limestone powder, no matter used alone or blended with fly ash or ground blast furnace slag to form a double-doped material, can be used as mineral admixture for the dam concrete including conventional and roller-compacted concrete. Compared with fly ash, it increases concrete water content and improves the 7 days strength, but almost has no function on the 90 days strength.

Abstract: The pore structure of cement-based materials is closely related to the freeze-thaw resistance durability. And this paper focused on nanometer pores to verify the connection of freeze-thaw cycles in the nanometer pores with the structure deterioration and to explore the stress in the pore wall during the freeze-thaw process. And BET method was adopted to analyze the pore structure of the cement and results indicated the changing trends of parameters such as the pore volume, average pore size and surface area of specimens. Moreover, pore size distribution presented prominent fluctuations of pore sizes in the range of 0 ~ 20 nm, while the changes on the scale of 20 ~ 100 nm were limited.

Abstract: Due to the frequent northwest wind, many times of earthquakes and floods, as well as the loose soil and higher underground water level, the famous pagoda has been in the tilt for many years. Rectification measures include foundation stabilization, landing, grouting, drawing out soil, water-injecting, so on. Be sure to make model test before operation.

Abstract: Through eight groups of room model experiments based on bucket foundation, P-S curve can be plotted for each group according to the experiments results and be able to get the ultimate strength and ultimate displacement for them. Therefore how the ratio of the ultimate vertical bearing capacity and the ultimate displacement changes with the ratio of diameter to height can be analyzed. When the ratio of diameter to height is less than 1.2, the ratio of the ultimate vertical bearing capacity and the ultimate displacement changes significantly; and when the ratio of diameter to height is greater than 1.2, the ratio of ultimate vertical bearing capacity and ultimate displacement is not affected obviously. When the ratio of diameter to height is 1.2, it reaches the maximum utilization of the materials, and the cost of the project can be effectively reduced. So the paper considers that the ratio of diameter to height = 1.2 can be used as the optimum point of the ratio of diameter to height of the bucket foundation.

Abstract: This paper performed numerical simulations of effects of unloading on occurrence of rock lateral cracks by using the numerical analysis software. The results indicate that the probability of median cracks and Hertz cracks occurrence was decreased due to the residual stress caused by stress mismatch during unloading, while the probability of lateral cracks occurrence was increased. The lateral cracks were tended to occur with the increasing of the amount of unloading and confining pressure. And the initiation direction of lateral cracks is more parallel to the rock surface, although the initiation direction became the same at the end. The relative positions of lateral cracks occurred were more concentrated during unloading process under the same confining pressure.

Abstract: This paper explores the comprehensive perspective of Historic Urban Landscape (HUL) through the evolution of cultural landscape theories as well as World Heritage cultural landscapes. It analyzes the adaptation of HUL in Chinese cultural, political and social context. In particularly, it proposes a thematic framework for the application of HUL in historic cities in China. The framework consists of three main themes and several sub-themes embracing dimensions such as perception of landscape, land-use, ways of life, spiritual or social-economic associations with landscape, and tools which can be used for identification of value. The research attempts to highlights the contribution that the HUL approach could make to the existing planning and management system for the conservation of historic cities in China.

Abstract: Non-autoclaved and non-sintered fly-ash perforated brick is a kind of new material for non-load-bearing walls. In order to promote the application of this new material in village and town buildings of seismic area, compression and shear strength of non-autoclaved and non-sintered fly-ash perforated brick masonry was tested and crack and failure progress was analyzed. The test results show that the failure processes and characteristics of the non-autoclaved and non-sintered fly-ash perforated brick masonry in compression and in shear are similar to that of the common brick masonry, however the non-autoclaved and non-sintered fly-ash perforated brick masonry tend to fail in brittle manner. The compression and shear strength are all less than that of the common brick masonry. A mathematic model of 6 degrees polynomial was used to express the compressive constitutive relationship and the whole process of non-autoclaved and non-sintered fly-ash perforated brick masonry in compression was described. The curve was close to the measured data.

Abstract: The wind-induced vibration control and analysis of a super high-rise structure located in the area of strong typhoon with viscous damping walls is introduced. Mechanical properties and design method of viscous damping wall are described, and then the arrangement scheme is put forward. The performances of structure with and without viscous damping walls under the condition of basic wind strength encountered once for 10 years are investigated in detail. The results show that the control scheme can dissipate energy of wind-induced vibration, attenuate structural dynamic response and reduce the mutation of acceleration along height direction effectively. The maximum peak acceleration can be reduced by 23.5% to 0.241m/s2, which meets 0.25m/s2 limit value stated by Technical specification for concrete structures of tall building. Therefore, the arrangement scheme is feasible and effective to control wind-induced vibration and improve structural safety and comfort.

Abstract: Under the influence of floor, the reinforced concrete frames have never realized the yield mechanism of strong column and weak beam which is a seismic design principle. To study the influence of realizing such yield mechanism because of floor with opening, its necessary to establish two frame models that one is with common floor and the other is floor with opening around the joints whose size is 600mm×600mm by the ANSYS that is finite element software. Moreover, these models apply the seismic loads and carry out the time history analysis. The results show that the frames stiffness has been weakened after the floor is opened, the peak acceleration reduced and the displacement increased. However, the ductility has been strengthened, which slightly reduce the reaction of the acceleration and displacement. In addition, the appearance of the plastic hinges in the beam are advanced, and the development of their plastic deformation becomes quicker than those of columns, and the plastic hinges in the bottom of the column are delayed. Therefore, the measure of opening the floor can realize the ideal yield mechanism of strong column and weak beam to reach the seismic target that the building cant collapse under the strong shocking.