Applied Mechanics and Materials Vols. 204-208

Abstract: It’s very necessary to do research on bridge splicing method, because it must refer to splicing problems between new and old bridge during expressway widening engineering. Now there are three main splicing methods: non-splicing for both superstructures and substructures, splicing of superstructures and non-splicing of substructures and splicing for both superstructures and substructures. Now splicing of superstructure and non-splicing of substructure is used more than other two splicing methods. Each splicing method has several different new construction technologies and their aims are to decrease the splicing disease. At present our country has accumulated lots of splicing engineering experience, so the following engineering should assimilate former experience and do incessant improvement and reformation.

Abstract: Based on the theory of ANN (Artificial Neural Network),The paper raised the method of construction control, and introduced the common forecasting method. According to the characteristic of ANN itself and the complexity of factors which influence the elevation, the paper analysed the influence aspects of ANN. On the promise of bridge construction precision, the paper raised section measure、elasticity model、temperature、delay of construction and cantilever for neural network’s input vector in bridge construction process. With the help of Graphical User Interface, built ANN, made the forecast function in the bridge construction into reality. Introduce the theory of Artificial Neural Network(ANN) into long span prestressed concrete continuous rigid-frame bridge construction control.

Abstract: Nowadays,issues regarding deflections at mid-span and cracks existing on the box girder of prestressed concrete continuous rigid-frame bridge have raised researchers’ attentions in China.To solve these issues, research is conducted on the influence of rigid steel framework at closure segment of the box girder in the process of the cantilever construction of the PC continuous rigid-frame bridge. Finite element analyses are carried out through ANSYS to investigate the distributions of internal forces and stresses in rigid steel framework inside and outside the closure segment of the bridge. Further, the normal stresses of closure segment under service load and overloading conditions are evaluated and compared. Results show that the stresses redistributed to the inner rigid steel framework decrease 16.7% after post-tensioning operation, causing insufficient compressive stresses at the bottom flange of box girder around closure segment, and inner rigid steel framework may produce cracks on the bridge which should be considered seriously in the design and construction.

Abstract: The technology of cantilever casting construction was complex for reinforced concrete arch bridges. This paper described key technologies of construction and control of concrete arch cantilever casting construction. The article introduced on cast-in-place support, fastening tower, hanging basket and anchorage system in cantilever casting construction. Based on the results of arch ring stress and arch ring camber, the methods of construction control were established on arch ring alignment, arch ring stress, cable force and tower displacement during the arch construction. Ensure the structure safety and make the structure's internal force reasonable, the compressive stress of arch sections is less than 10MPa, tensile stress of arch sections is less than 1.5MPa in construction of concrete arch cantilever casting.

Abstract: With the development of prestressing technology, steel strand first should the hollow plate beam of prestressed concrete get in the upper part structure of the highway bridge extensive application, to steel strand first should prestressed concrete hollow plate beam construction quality of quality, not only direct relation arrive bridge of normal usage, also in the meantime relation arrive bridge of safety degree and durable. Therefore acquaint with in the beam system make the process with control first a construction a craft with work well quality control the key being very. This text combine a construction to practice, to steel strand first should prestressed concrete hollow plate beam construction craft, quality control the etc problem make an introduction.

Abstract: As a bridge assessment method, risk assessment is more and more applied to load-carrying capacity assessment of existing bridge. This method assesses the bridge through the failure risk value which calculated by the failure probability and failure loss value. The most important factor to the risk assessment of load-carrying capacity upon the existing and diseased bridge is the calculation of failure probability. This paper combines the reliability calculation theory with a certain site detective data of bridge that considering uncertainty of load and resistance along with the diseases of bridge, and induces in the correction coefficient of load and resistance respectively to calculate the failure probability and reliability index of bridge. Finally, these indexes are compared with those provided by the current code to implement risk assessment of load-carrying capacity of the bridge.

Abstract: Port coastline is the basic resources of port construction, not only scarce, but also non-renewable. It is the national precious strategic resources. The value assessment of port coastline is an important theoretical basis on the sustainable utilization of port coastline resources. In this paper,via the definition of port coastline value connotation, in-depth analysis of the necessity of value assessment and its theoretic foundation ,finally the paper has made systematic assessment to the port coastline value by using of comprehensive weight method and fuzzy comprehensive evaluation method.

Abstract: With the rapid development of social economy, silt coast exploitation becomes the main approach to make up the imbalance of harbor resources in China, although the inherent problem of sedimentation has not been fully addressed. Due to the special geomorphology and complex sediment transport near silt coastal zone, the sediment dike, as a traditional construction, plays an important role in maintaining port operation and decreasing the siltation. In present paper, using the Guang-Ao harbor district planning project in the south coast of China, different dike arrangement schemes have been compared based on numerical simulations. The sediment transport characteristics and the latent erosion and siltation trend under these schemes have been discussed. Results show the importance and necessity of a proper design of dike near silt coastal zone, which can guide the sand transport path and reduce the possibility of sand intrusion in harbor zone. Present research provides a reference for other engineers to design and optimize the harbor design, especially in zones with high concentration of suspended sediment.

Abstract: The paper aims to present the authors’ research on application of engineering fuzzy set theory analysis to reservoir ranks rock slop stability evaluation by using analytic hierarchy processing (AHP). Many methods, which used to analysis highway slope stability, are compared in the paper. On the basis of research on the general slope stability evaluation methods, lots of fuzzy factors of stability evaluation for highway slope are researched and fuzzy comparison matrix model is established. Correspondence relationship between mood operator and fuzzy value are determined. Evaluation indexes and grading standards are identified on the basis of engineering practice. The weight of every index is obtained by using analytic hierarchy processing and the method of Ridge-type distribution, which the method of combining with the bigger the more excellent and the smaller the more excellent. Engineering fuzzy set theory is used to make a comprehensive evaluations, overall evaluation of the highway slope stability is obtained according to the principle of maximum degree of subjection and the result of subjection degree vector. Slope stability evaluation of AN-SHAN Expressway is analyzed with analytical hierarchy process. Evaluation results provide a basis for the progress of the project, and the project carried out smoothly with the guidance of it. The results show that the model makes slope stability evaluation more comprehensive, scientific and rational.

Abstract: Zhenshui is the biggest tributary of Xiaolangdi Reservoir and its original storage capacity is 1.767 billion m3. By October 2010, the amount of sediment in Zhenshui reached 0.1691 billion m3, and the sand bar at Zhenshui estuary was 7m in height. Influenced by operational mode of reservoir and terrain, the formation of sand bar has certain inevitabilities. The sand bar can prevent water and sediment exchange between mainstream and tributary, and the internal storage capacity of tributary is not effectively used. The experimental result shows that during the later sediment retaining period, some small reservoirs can be built at the end of Zhenshui. By restoring water during the high water level in non-flood season in these small reservoirs and discharging flow during the low water level in flood season to scour sand bar, the tributary and main channel in Xiaolangdi Reservoir can be linked up in long term, service efficiency and life of tributary storage can be increased.