Papers by Keyword: Foundation

Abstract: One 6-stories brick-concrete structure was built in the late of 1990s. The uneven settlement of the foundation had occurred and the average concrete compressive strength of the foundation was close to C30 standard. Apparent observations indicated that some white powdery substance which was not adhesive was precipitated at the aggregate/mortar interface, pores and cracks. Micro observations by means of a Scanning Electron Microscope equipped with a Energy Dispersive Spectrometer showed the coexistence of ettringite and small amount of alkali–silica gel, which proved that the foundation had suffered from sulfate attack and alkali–silica reaction.

Abstract: Due to inappropriate protective measures during construction, building structures in cold regions can easily suffer from frost heaving damage during the wintering period. Such damage is relatively invisible and can hardly be detected. According to the actual engineering conditions, this paper comprehensively analyzes the destructional form of each building element at low temperatures as well as discusses the methods to detect and evaluate damage of buildings at low temperatures. The author finds that: Under low-temperature environment, punching failure often occurs between the foundation slab and bearing platform and the anchor connection between the pile and bearing platform can easily become ineffective.

Abstract: The soil mechanics and foundation is a course with strong theoretical and practical features. Based on the possible problems in the teaching process, the author provided some considerations and suggestions such as transforming teaching concept, strengthening the systematicness of the teaching content, electing textbook and improving teaching method, increasing the interest of student, valuing the practical teaching link. A series of inside and outside tests at school were introduced to help the student master knowledge in all aspects.

Abstract: Fundamental to the IMP, is the requirement to provide a harmonized data model and represent it appropriately, including geometric tolerances information that can be understood well by computers and users. In this paper, we propose a layered conformance level geometric tolerances representation model. This model uses the widely applied ASME Y14.5M-1994 as its foundation layer by abstracting most information from this standard. Thus, different application domains in an enterprise can use this data model to exchange product information. This model is further transformed with XML Schema that can be used to generate XML instance file to satisfy geometric tolerances representation requirements in IMP. Fig.1 A typical feature control frame and its possible symbols. Fig.2. Example part.

Abstract: The effect of the centrifuge strongbox boundary on the penetration resistance of a spudcan foundation in uniform clay has been studied using Large Deformation FE analysis. Both smooth and rough strongbox boundaries were considered with various strongbox sizes. The spudcan penetration resistance and soil flow mechanisms were analysed. It was observed that, when the strongbox size was reduced, the spudcan penetration resistance was decreased for a smooth boundary and increased for a rough boundary. The depth of cavity formed above the spudcan during its penetration, in most cases, was determined by the soil flow around mechanism without cavity wall failure. However, cavity wall failure could be initiated when a smooth strongbox boundary was very close to the spudcan. The strongbox boundary effect on the spudcan penetration resistance can be avoided when the distance of the strongbox boundary to the spudcan centre is larger than 1.5 times of spudcan diameter for a rough boundary; or 2 times of spudcan diameter for a smooth boundary.

Abstract: This study is conducted to evaluate analytically the effect of casting temperature on the heat of hydration in mass concrete foundation with ternary cements and Type IV low heat cement. The mat foundation has the dimension of 15m length, 20m width and 3m depth. Casting temperatures considered for mat foundation consist of 10, 20 and 30C ̊. A commercial software MIDAS/Gen was used to analyze the hydration heat of mass concrete foundation. The maximum adiabatic temperature rise (K), and the coefficient of temperature rise˰˸α˹˰for thermal analysis were drawn from adiabatic temperature rise test. Analytical results show that blended cement PSLB_352 is the most effective to control the heat of hydration in mass concrete foundation and external temperature increases the maximum heat of hydration and crack probability of mat foundation with mass concrete.

Abstract: When there is a ramp, the methods of calculating the foundation and pile bearing capacity are different from the plains situation. Many scholars have been studied determination method of the foundation and pile bearing capacity under the condition of slopes. A program is developed based on the results of previous studies, which can calculate the foundation and pile bearing capacity under the condition of slopes. The program using MATLAB software integrates a calculation method of foundation and pile capacity under slope condition. Combined with numerical examples, the results illustrate the upshots of the calculation methods in the program on the basis of the literature by interpolation method with the adjustment coefficients are accurate. And analyzed the influence of slope ratio on the bearing capacity: capacity and slope ratio was negatively correlated, with the slope ratio decreases, the capacity is on the increase, but the degree of increase based on the slope ratio.

Abstract: The superstructure and foundation of highrise are in a complete system of interaction. Taking the case of project, by comparatively analyzing the computed value which is calculated by applying the theory of interaction between superstructure and foundation and the measured value ,we find that the computed value neatly dovetails with the measured value.

Abstract: The purpose of this study is to enhance productivity and economic value with precise object information generation and reinforcement quantity take-off by developing the Automation Reinforcement Placement System of Foundation (ARPF). This study was conducted by selecting the most basic form, spread footing, and no force was applied on the foundation other than axial force. For the development of ARPF, variables that should be input into the typical programs directly by users were minimized through developing the reinforcement placement algorithm by using visual C# based on the reinforced concrete structure design standard. The process of reinforcement detail placement formation was performed in the Tekla Structure (TS) that has outstanding accessibility and usability of API. Objects made by applying ARPF enable information confirmation and modification, as typical ones. Through this process using ARPF, rapid and precise reinforcement quantity take-off and footing bar placement are possible. If modeling is performed on the Tekla Structures by using ARPF, a detailed 3D reinforcement placing drawing, not 2D, can be created. It is expected that this method may take a smaller amount of time and effort than the typical drawing generation method that users had to generate objects or input information themselves.

Abstract: Based on a kind of 1.5MW large-scale horizontal axis wind turbine tower, the mechanical modeling of a wind turbine tower-foundation is established, the static and dynamic analysis of the model is carried out by ANSYS software. The top displacement of the system is calculated by the static analysis to meet the design requirements in engineering. In dynamic analysis, each pile foundation is equivalent to a group of springs for the simulation of horizontal and vertical rigidity of the pile. The influence of top mass and foundation elasticity on wind turbine tower modes is analyzed, and calculated the natural frequency of the tower within a certain scope of rigidity in different directions about the piles foundation. The results show that the natural frequency of the wind turbine tower is influenced significantly by the mass on the tower top and foundation rigidity. The study provides a theoretical basis for optimal design of the wind turbine.