Advanced Materials Research Vols. 919-921

Abstract: Under wind action, the property of non-Gaussian wind pressure distribution is very important for determination of peak factor, simulation of fluctuating wind pressure and design of cladding and components. Since the distribution of non-Gaussian zone is highly irregular based on the statistical method, any effort on giving regular non-Gaussian zone regions cant reflect the real non-Gaussian property. Considering the fact that non-Gaussian property was induced by flow separation and generally the movement of vortex showed the character of time averaged steady, taking a typical low-rise building as the example, the distribution of limiting streamlines and the theory of flow separation was applied in the research. Results show that the distribution of limiting streamlines has a close relationship with the intensity of non-Gaussian property and can be used as an intuitionistic tool in the research of identification and mechanism for non-Gaussian properties.

Abstract: The comparison between the experimental results of bending rigidity of recycled concrete collected from the bending test carried out by domestic and overseas researchers and the calculated results by formulas from available codes is done. The results show that formulations of from available codes are not suitable for recycled concrete beams. Then, based on the factors that influence the bending rigidity of recycled concrete beams, the formulation of bending rigidity for recycled concrete beams is proposed by theory. The experimental results by this the formulation and the test results is very close, the mean value and variation coefficient of the ratio of experimental value and calculated value for recycled concrete beams is respectively 1.01 and 0.16.Keywords: recycled concrete beams;bending rigidity; deflection; formulation

Abstract: Mingzhou bridge in Ningbo is a half-through steel box arch bridge with 450m main-span. The bridge adopts welded steel structures except that abutments are made of steel composite structure. High requirements for the bridge construction technology are put forward because of the restrictions including poor geological conditions for bridge site, height limit for aircraft, narrow channel, frequent typhoon. The mid-span arch rib adopts cable hoisting and stayed buckle cable technology for the construction. This paper introduces the construction method during the assembled process of the mid-span arch rib. The numerical simulation analysis for the construction process is carried out. Stress and deformation of the main arch are in a reasonable range, which indicates completing the bridge construction control target successfully.

Abstract: Silo structure has been widely used in the industries in China, such as chemical engineering, coal industry, light industry, fodder industry and grain industry. Nowadays, reinforced concrete silo structures have been the most general form. Due to the special features of silo structure, there have been some particular part such as baseboard and hopper. Meanwhile, the level of the baseboard is always high and the configuration of the hopper is complex. Therefore, a lot of construction difficulties and problems have been generated in the progress of silo construction. Based on practical engineering, a series of construction technologies for ultra-high baseboard and hopper of silo were proposed in this paper. With a review to the structure features of the ultra-high baseboard and hopper, an applicative formwork scheme was designed and carried out in the construction. By means of the proposed formwork scheme, some key problems were well solved and the whole engineering quality were ensured. And it has certain reference significance to the construction of this engineering.

Abstract: One deep foundation pit in Hefei urban rail transit project is adjacent to the existed expressway subgrade, it's in the unsymmetrical loaded state. The control of foundation pit deformation and the safety of subgrade must be strictly ensured. Based on it, the design scheme of supporting system, the construction processes of earth excavation, top beam, concrete support and steel support was introduced. The horizontal displacement of fender piles and the settlement of subgrade was monitored. The field monitoring results indicate, there exists a great difference between the retaining structure deformation under the action of unsymmetrical load and the deformation under the action of symmetrical load, the horizontal displacement of fender piles on the side of subgrade is bigger than the other side, the upper pile appears to be a "drift" towards the lower-load side; although the absolute value of horizontal displacement of fender piles and settlement of subgrade seems to be a big number, the relative value is small compared to the whole length of fender pile and expressway, meeting relevant standard requirements. The deep foundation pit and expressway kept safe and stable in the all periods of construction, no one accident was occurred during that time. Thus, it can be seen that this construction technology is effective in controlling the deformation during excavation, which can provide a reference for similar projects in design and construction in the future.

Abstract: Urban development often requires the construction of deep excavations. There are some difficulties during design and construction of foundation excavation, such as large engineering quantity, poor geological conditions, as well as challenges to design and construction of retaining and protecting structure. To solve these difficulties, supporting system of steel circle beam, steel pipe support and stiffened support compounding with steel pipe pile cofferdam is designed. Soil resistance calculating method is used for support structure design in all possible conditions and the result is compared with that using the classical method. With reasonable supporting process and construction measures, monitoring results including displacement of steel pipe piles and greatest axial force can meet the norm requirements. It is proved that the retaining and protecting system designed is safe and reliable. With the benefit of small deformation and high integrity, locking steel pipe piles gave full play to its locking function of water. The design method in the paper is feasible and may offer some references for similar deep foundation excavation.

Abstract: Mass concrete is widely being used in the construction field, especially for the foundation of super high-rise building. In the initial stage of pouring completion of mass concrete, lots of heat generated from the cement hydration will lead to a high temperature inside of concrete. When the temperature difference between the inner and outer of concrete exceeds the limited value, thermal stress will be greater than the tensile strength of concrete, which may cause hazardous penetrating cracks of the structure. To ensure the safety and durability of concrete structure, necessary measures should be taken to control the temperature rise and construction quality of concrete. Taking a super high-rise building project as an example, this paper introduces several effective solutions to resolve above problems. The technical measures such as enhancing the concrete quality, controlling temperature rise, strengthening temperature monitoring would be detailed illustrated. Meanwhile, valuable suggestions achieved from this practical project are proposed in order to guide the structural design and on-site construction of similar projects.

Abstract: The second design of construction drawings is an important part for building. It is not only a simple analysis and a modification of the drawings, but is the purpose to save cost using re-designed based on construction plan and techniques. For this purpose and other advantages of second design, the current large-scale projects, especially high-rise buildings, are required for secondary design. This article mainly introduces the second design, and uses the value engineering and the weighted average method to analyze the problem of cost savings and allocation. It proposes the approaches and methods of cost savings through the second design, obtains a reasonable method of allocation ratio calculation and general distribution ratio, as well as provides a strong reference to improving the economics of high-rise buildings.

Abstract: The project cost industry got rapid development with large scale development construction projects in china. The government's management departments of project cost, in order to provide the capacity and level of management, the transformation of the mode of management, strengthening the project cost information service function, implement the informatization strategy comprehensively. But in the country, because of the lack of unified project cost information technology planning, and construction standards, resulted in the formation of many "islands of information". Therefore, the article proposes information management system integration of project cost for the management department of project cost to meet the urgent needs of project cost sharing and using.

Abstract: Earned value management (EVM) is one of the most widely used control tools in project management. It is a well-known management system that integrates cost, schedule and performance. Based on the traditional concept of EVM, the cost/schedule monitoring and forecasting model is proposed in this paper. It gives us the analysis steps and provides the methods for monitoring the actual situation and forecasting the final cost and duration. By using this model, the managers are able to know timely the status of a project in terms of budget and schedule and forecast the developing trend and ultimate outcome of the project. So it is a reliable method to improve the capability of project managers for making reasonable decisions.