Advanced Materials Research Vols. 1049-1050

Abstract: To research the mechanical regularity of steel frame in tunnel, Steel frame and Sprayed concrete Combination Model is applied and the large-section loess tunnel of highway is taken as an example. The hoop stress of flange and the radial stress of web were analyzed, the research results show that:The most areas of hoop stress of flange is in press, the compress value which most areas of flank edge is larger than the outer flank flange in the same area of steel frame. The hoop and radial stress of web is in press. The hoop stress value which most areas of flank edge are larger than the radial stress in the same area of steel frame.

Abstract: Centrifugal modeling technology has been applied to geotechnical engineering for more than half a century. It has been an important and indispensible means to simulate the geotechnical behavior because it has the same material, the similar boundary conditions and the same stress level. And it is also commonly used in tunnel-related research. Centrifugal tests of pipe-roof and small pipe grouting in tunnel were analyzed, the important effects of centrifugal tests on preliminary support of the tunnel were also emphasized. Problems often met in model tests of tunnelling were solved, such as structure model, modeling soil, preliminary support model and general programming of experiment proposal. The future development of centrifuges in tunnelling is also presented.

Abstract: In wall-column structural system of electrostatic precipitator casing, wall will share the load with column and provide lateral bracing support when the load is applied on the column .Then the wall panel exert the stressed skin effect, which will influence its load bearing capacity. By nonlinear finite element method, when wall panel exerts stressed skin effect, whether the effect will influence the wall bearing capacity is investigated as well as the failure mode. The relationship is analyzed between the loading level onto column, panel thickness, loading form onto wall and the affecting degree on the bearing capacity of wall panel. The computation results indicate that the bearing capacity of wall panel is lower when it exerts the stressed skin effect. When the wall is thin, the weakening degree of panel bearing capacity resulting from stressed skin effect is slightly affected by loading level onto column. When the wall is thicker, the weakening degree of panel bearing capacity increases apparently as the loading level onto column increases. For a certain loading level onto column, compared with the locally loaded wall panel, the impact on load bearing capacity is greater for the globally loaded wall panel. Research work has reference value for the calculation and design of enclosure structures of electrostatic precipitator casing.

Abstract: This paper mainly researched on preparation and the setting time of Magnesium Phosphate Cement (MPC). The method of orthogonal experiment was adapted to determine the best ratio of MPC, and change the content and types of the material according to the influence of various factors, so as to get the longer setting time of MPC. The results showed that, when the water cement ratio is 0.12, the factors significantly influencing the setting time is magnesium phosphorus ratio (M/P), fly ash and borax. The optimal mixture ratio was obtained through the orthogonal analysis, namely M/P is 3/1, borax content is 16%, and the amount of fly ash is 40%. When M/P is 1/1 and 2/2, borax content is not more than 22%, and the amount of fly ash was less than 60%, the longer setting time of MPC can be produced.

Abstract: When the bearing capacity of natural foundation cannot meet load requirements, generally the ground treatment usually can be taken to strengthen it. In this paper, from the practical engineering, the design, construction, and detection of the lime soil pile were introduced. The results show that the lime soil pile in collapsible loess area reinforcement technology foundation is feasible. The bearing capacity and stability of the treated foundation can meet the requirements.

Abstract: Mobile steel building is a prefabricated building built in a factory, with advantages on moving conveniently, simple structure and scalability. There are still not enough relevant standards and requirements to conduct the design and construction of this kind of buildings. In order to precede to theoretical study on integral structures of mobile steel buildings a method which used to set up finite element analysis model about this kind of structure was proposed. This method is based on finite element analysis software, ANSYS. Using this method a two-story structure model with one box unit in each story was analyzed. Lateral deformations under design load of the integral structure were solved out by these finite element models and were compared with the former experimental results, and the results were discussed.

Abstract: The mechanical properties of axial compression aluminium members under cyclic loading were studied and compared with those of steel columns. In order to proceed to theoretical study on hysteretic behavior of aluminium columns, a method by finite element analysis was proposed. The method was based on FEA software, ANSYS. The analysis methods considered the effects of material nonlinearity, geometrical nonlinearity and initial imperfection. On this basis, hysteretic curves, reversal skeleton curves and stiffness degradation curves of 6061-T6 aluminium columns, 6061-T4 aluminium columns and Q235 steel columns under axial cyclic loading were obtained and compared. Results show that the hysteretic behavior of the aluminium columns is similar with the low carbon steel columns and is significantly influenced by constitutive relationship.

Abstract: The fatigue cracks are inevitably existed in steel bridges after they are working for a fairly short time because of the environmental pollution, overloading vehicles and larger numbers of automobiles. Due to the fact that the scholars have put few emphases on the influence of corrosive environment which inevitably affects the fatigue property of steel bridge, an experiment design of corrosive and fatigue property of steel box girder with the specific environment controlling equipment is taken into account. Through the data from the experiment design, the important residual strain can be gained, which can be used for the analysis of the damage developing regularity.

Abstract: A tensile test on the 18mm diameter (φ18) and 25mm (φ25) GFRP bars was conducted to observe the tensile apparent characteristics and failure strength. The value calculated by failure strength fomula and the experimental value were ,contrasted to study the parameters and value of the strength calculating formula,, and drawn the conclusions as follows: The φ18 and φ25 GFRP bars' failure strength is effected by fiber materials, enhance materials itself and interface performance. The φ18 bars’ failure strength is about 10% higher than φ25 bars’. The deviation between the calculated value and the actual value is more than 30%. k is the correction parameter in theoretical formula, k_φ18=0.76, k_φ25 = 0.68 is appropriate. Based on statistical intensity distribution model of GFRP bars’ failure strength, reference stresses value of the φ18 and φ25 GFRP bars are different and the diameters of GFRP bars increases to weaken the strength of the composite material. The reducing rate of the reference stresses is significantly affected by the diameters. The diameters effect is greater than the fiber content effect.

Abstract: The main objective of this paper is to analyze the principle of low-noise pavement, safety performance and comparison with other noise reduction measures. Furthermore, combining some engineering cases, we analyze the principle of noise reduction for low noise asphalt concrete, and compare the low-noise asphalt concrete with ordinary asphalt concrete. Finally, we sum up the advantages of low-noise asphalt concrete.