Advanced Materials Research Vols. 446-449

Abstract: The water area in which water depth is deeper than 50m has special advantage in wind turbine generation, because there are the stable wind speed and small Wind-shear. In such sea area, the offshore wind energy generating equipments should be set up on floating foundation structure. Therefore, it is of great significance to study the floating foundation structures that are available for offshore wind energy generation for the industrialization of the offshore wind power generation. In this paper, the basic type and working principles are reviewed for some novel floating structures developed in recent year. In addition, some key dynamical problems and risk factors of the floating structure are systemically analyzed for working load caused by turbine running and sea environment loads of floating structure. The results are valuable for designing the floating structures of wind turbine generation.

Abstract: Bending properties of steel-concrete box beams with three different design parameters are tested under the function of monotonic load to better understand the influences of degree of shear connection and height-thickness ratio of web on nonlinear property, bearing capacity and failure modes thereof. In addition, study on failure modes, slip between the concrete desk and the steel box beam, overall service behavior of the cross section, bending bearing capacity of the normal section, shear lag, etc. is conducted on composite box beams, through which, the failure modes and degree of shear connection of composite box beams are proved to be related to the height-thickness ratio of the web. Finally, slip distribution and relation between slip-strain curves and strain curves of vertical distribution of composite box beams are made clear.

Abstract: The applicability and durability proportions of the main structures in concrete bridge were determined based on AHP, and the influence degree of different influencing factors on applicable and durable structures of concrete bridge were also analysised, which laid the foundations of applicable and durable configurations study of concrete bridge.

Abstract: A self-centring bridge pier is a combination of elastic recovery devices and internal or external energy dissipaters. During the cyclic loading test, it is proved that the self-centring system can minimize the residual drift of the pier whereas holding sufficient energy dissipate capacity as well as bearing capacity. It is worth noting that a simplified analytical model is proposed based on the experimental response regarding flexural deformation, unbounded length of mild steels and strain penetration. Comparison between the analytical model and test results has indicated that a reasonable envelope of the cyclic behavior of the system can be achieved by the model presented.

Abstract: Based on the background of Xinghai Bay Sea-crossing Suspension Bridge, it reviews the development process of Suspension Bridge anchorage and describes the static theory of gravity anchorage of suspension bridge. Using the soft ansys, a three-dimension finite element model of the suspension bridge anchorage is established to analyze the overall stability of the anchorage foundation, the displacement and stress conditions. The anchorage in various load conditions of displacement and stress is studied by numerical calculation and comparison. The analysis result shows that the first slip area is not in the outer end of the contact surface, and there is a certain distance. The area beginning to slip also increases with the loading nodes increasing. As the level of the load increases, the slip region has gradually developed, the contact surface in the first sliding part opens slowly. The slip area expands to the entire contact surface except for a contact surface opening area with the contact surface in sliding failure.

Abstract: The mechanical behavior of the support regions for continuous composite girders with tensile stresses in the concrete slab and compressive stresses in the lower steel profile becomes strongly nonlinear under negative bending moments. A static test on four half-scale model of a steel and concrete composite girders with different shear connectors including studs and PBL under hogging moments was conducted and observed to evaluate the influence of shear connector on inelastic behavior such as flexural stiffness reduction, crack initiation and development in concrete slab. From the test results, the flexural stiffness and loading capacity of the composite girders were improved by PBL shear connector. Higher initial cracking load and crack resistance stiffness of composite girders with PBL shear connector under serviceability limit state was obtained during crack development process. The test specimen could be assumed as full composite section until the ultimate state from load-slip relationship of shear connector. Analytical and experimental studies can serve as a basis for continuous composite bridges design.

Abstract: In this paper, the the micro crystallization behavior of MgO-SiO2-Al2O3-B2O3-KF glass-ceramics which was prepared by sintering and water quenching method was discussed. The study indicated that the compacts shrinkage of MgO-SiO2-Al2O3-B2O3-KF glass-ceramics were related to its vitrification and its component crystallization degree; about the density of sintered compacts, the higher the crystallization degree, the higher the dense it owns. The conclusion reached above is significant in dimension control to the produce process. In the samples when the proportion of ingredient was closer to the atomic ratio of mica crystal, the higher the micro crystallization degree of the glass-ceramics will be. When sintering temperatuer is 1000oC,the MgO-SiO2-Al2O3-B2O3-KF glass-ceramics begain to present the crystallization; when it achieves to 1050°C, the crystallization degree is highest; continue to increase the sintering temperature, the micro crystallization will be melted again.

Abstract: Combined the design of a long-span continuous rigid frame bridge of a highway in Pearl River Delta of China and based on the longitudinal and lateral force characteristics of the large span, wide margin and wide box structure, the appropriate principles and methods to determine the index of the parabolic line is raised through analyzing and comparing the impact of the gradient law of the parabolic beam height of different index on structural forces.

Abstract: Over-deflection of beam in continuous rigid frame bridge has become an serious problem in recent years. The reason is complex. Some reseachers think that the bad quality of sectional joints in cantilever construction will cause additional shearing deformation and affect the beam deflection, this idea need to be further studied. In the paper, two three-dimensional models are built up based on a factual bridge, the simulation method of sectinoal joints is studied. The influence of concrete creep on the deflection of box beam with sectional joints is analysed being compared to beam without sectional joints . In order to simulate concrete creep, a method of effective elastic modulus adjusted with concrete age was applied. The study shows that the shearing deformation of sectional joints has obvious influence on the long-term deflection , and different calcultion method of concrete creep has different effect on it. It shouldn’t be ignored in the bridge design.

Abstract: The continuous rigid frame bridge has been applied widely in our country. But in recent years, over-deflection of beam in this bridge has become an serious problem. This may cause the redistribution of displacement and internal force of the whole structure, especially in dynamic load status. A two-dimensional pile-soil-bridge model is built up in ANSYS based on a factual bridge. The over-deflection is considered as the decrease of beam elastic modulus or rigidity. The displacement and internal force of key parts are analysed in static and dynamic vehicle load. The study shows that over-deflection will reduce the first three natural vibration frequency, weaken the sensitivity of bridge to dynamic load. In dynamic load status, the displacement and internal force will be influenced by beam rigidity.