Advanced Materials Research Vols. 374-377

Abstract: The development of the permanent deformation of subgrade soils under repeated load tests may consists of three stages, namely the primary, secondary and tertiary stages, but the existing models can not describe this behavior very well, so a new model is required to be developed. Based on the creep equation of the soil under static load, a mechanistic model is developed to describe the development of the permanent deformation of the soil under repeated load tests. Triaxial repeated load tests are conducted for silty soils and results show that, under some conditions, the development of the permanent deformation of silty clay consists of three stages and the number of load repetitions corresponding to the initiation of the tertiary stage is 330,0000. The new model is used to fit the test results and the comparison of test results and fitting results prove that this model can describe all three stages of permanent deformation.

Abstract: It is a complicated progress of interaction between pile and soil when pile is under both vertical load and horizontal load. This paper analyzes the variation of stress, strain, deformation and deflection of the pile body by finite element numerical simulation of single bored concrete pile under vertical load together with horizontal load. Based on the existing research results, conclusions could be that the vertical load can increase horizontal bearing capacity of the pile in sandy soils, but horizontal bearing capacity of the pile in clayey soils is more complicated. Hope that the simulation can provide some references for the design of pile foundation.

Abstract: A representative volume element is chosen to act as the research object to analyze the temperature field of the dispersion fuel elements. The thermal analysis is carried out for the thermal behaviors using FEM. The results indicate that with the volume fraction and the heat generation rate of the fuel particles increasing, the temperature and the gradient of the temperature in the matrix and the cladding increases markedly.

Abstract: Howard's Garden Cities of Tomorrow is the first professional book of modern city plan in general, but there are many misunderstandings of the book and writer today. To be strict, Garden Cities of Tomorrow is not a book of city plan simply and Howard is not a traditional city planner. Although Howard's idea of “Sociable Cities” involves clear thinking of social reformism utopian, Garden Cities of Tomorrow is the most important and influential masterpiece in the history of city plan in the 20th century.

Abstract: According to an evaluation on a six story, brick residential building with severe cracks and inclination, the influence of uneven soft subsoil on building was analyzed. Such damaged wall could be avoid, if the treatment to the basement and subsoil is correct in design and the brickwork is regulated strictly in construction. In order to minimizing the lost and keep the building safety, influence of uneven soft subsoil on buildings should be taken into account much more seriously, not only in design, but also in the construction process.

Abstract: The study of cover cracking pattern can provide scientific basis for the durability assessment and maintanence of concrete structures. In this paper, corrosion induced cover cracking pattern was investigated by accelerated corrosion test. The cover thickness c, bar diameter d and bar spacing s were considered in the test. Test results showed that the cracking pattern of cover concrete mainly included four typies, that is longitudinal cracks including wedge and vertical, parallel cracks, spalling and delamination. When the bar spacing was small enough, the delamination of cover concrete occurred which had nothing to do with the ratio c/d. When c/d≤1, the corrosion of side bar mainly induced the vertical cracks and the corrosion of corner bar induced both vertical and wedge cracks. While c/d>1, the corrosion of corner bar mainly induced wedge cracks.

Abstract: The effect of calcium leaching by nitric acid on fracture properties of concrete was experimentally studied. The double-K fracture parameters were investigated using three-point bending beams, and the deterioration regularity of fracture properties of concrete chronically attacked by nitric acid was gotten on basis of these results. The load-crack mouth opening displacement curves under different nitric attack periods were obtained by pasting some strain gauges onto the pre-crack tip. On basis of the double-K criterion, the unstable fracture toughness as well as the initial fracture toughness was calculated according to the critical crack mouth opening displacement, the unstable fracture load and initial cracking load which can be obtained from the test. The experimental results indicated that the ratio of the initial fracture toughness to the unstable fracture toughness varied between 0.47 and 0.61 approximately. Both of the unstable fracture toughness and the initial fracture toughness decrease with attack period especially during the early 60 days, then drop to a stable trend gradually. In addition, the initial fracture toughness is less sensitive to acid attack compared with the unstable fracture toughness.

Abstract: The actively prestressed strengthening technique of CFRP plate is a kind of strengthening technology with great application in the future. After a comparison and conclusion of the advantages and disadvantages of various prestressed tensile techniques for CFRP plate from home and abroad, based on the WSGG anchor, this paper puts forward the hinged anchor and a new technique where the hinged anchor tensions in vertical direction, the biggest characteristic of this technique is to ensure force uniformity of CFRP plate, consequently, high strength feature of CFRP plate can be fully developed. In addition, a series of improvement have been achieved, such as on-site baiting, fast clamping and rapid tensioning, etc. of CFRP plate. Hinged anchor and its prestressed tensile technique are firstly applied for the reinforced projects of Chongqing Xiaojia River Bridge and Chongqing Lianhua River Bridge, which promote rapid strengthening for the old bridges successfully.

Abstract: The Topological City is a design concept for a three-dimensional city in China. To accommodate future populations, cities need to be dense, diverse and ecological. Minimising the physical dimension reduces the consumption of material and energy and the destruction of ecological and agricultural landscapes. Mixed-use cities reduce the time, energy and congestion of travel. The integration of natural systems improves environmental quality and supports biodiversity. Ultimately however, the quality and functionality of contemporary urban life relies on dynamics of economic, social and intellectual interaction. The design form of a city must facilitate exchange between heterogeneous and changing programs while minimising energy and maximising habitat. High-rise construction is the dominant morphology of modern cities. Generated by an extrusion from the ground toward the sky, high-rise adds significant density but results in circulatory dead ends, structural inefficiency and habitat disconnectedness. High-rise is not interactive, energy efficient, or ecological. The Topological City proposes an alternate configuration of the urban environment. Drawing on the theory of place and connection known as ‘topology’, it constructs a three-dimensional network of vertical and horizontal towers, connected and activated by circulation. The Topological City is dense, diverse, ecological and interactive, suggesting a potential new direction for sustainable urban form.

Abstract: As the physical embodiment of urban commerce, the leasing of office buildings objectively influences the reconstitution of city space and the construction of commercial zones. By adopting Kriging in a geostatistical analysis module, this paper takes the rent of office buildings in Chongqing as the subject of research to construct a digital rent spatial model based on lease transaction data from 2009 with ArcGIS. Using the rent thematic map provided by this model and combining the specific circumstances of Chongqing, the rent spatial distribution structure is studied, so as to provide the basis for an approach to commercial land division and spatial planning.