Applied Mechanics and Materials Vols. 361-363

Abstract: As bridge span increases, people have growing concern on bridge safety and durability. The fuzzy comprehensive evaluation was introduced to assess complicated cable-stayed bridges. The calculate approach of fuzzy comprehensive evaluation was introduced first. Using the representation proposed by Professor Zadeh, the membership degree of the bridge technique status was described. The membership function of comprehensive evaluation for cable-stayed bridges was established by fuzzy statistics method. The application problem of model in the comprehensive evaluation for cable-stayed bridges was discussed, and the model was established in the composite calculation procedure of fuzzy sets. The fuzzy comprehensive evaluation theory was applied in the evaluation of the Sifangtai Cable-stayed Bridge as an example and the final results was basically consistent with that of the uncertain AHP method. It can be concluded that the theory can apply to the comprehensive evaluation of cable-stayed bridges.

Abstract: The new-type structure of "three towers of two-span" suspension bridge with the main span of 2×1080m is put to use in Taizhou Bridge. The foundation of Middle Tower adopts an extra-large underwater caisson structure with the three dimension size about 58m×44m×76m, which has been so far the deepest underwater caisson in the world. The caisson is divided into two sections, that is, Steel Caisson on the bottom and Concrete Caisson on the top. The underwater positioning, landing of Steel Caisson and the height addition construction of Concrete Caisson are of great construction difficulties and thus brought high safety risk. In this paper, Taking Taizhou Bridge as background, the safety control technology and management of underwater caisson construction is presented, which can play a good reference for similar projects.

Abstract: As its good mechanical properties, steel bridge has been widely used in modern highway, railway and urban bridge construction, but its corrosion protection is also a major issue. This paper studies the types of corrosion, the methods of anti-corrosion and focuses on coating protection--the most promising anti-corrosion method currently. It proposes some improvement measures for the corrosion protection, and has a certain reference value for the design and construction of such bridges.

Abstract: This study focuses on buckling analysis of steel cylinder in super long bored piles during construction. Due to special reasons, a steel sleeve is needed to be put into a 92m-long bored pile hole. On the basis of the theoretical estimation and numerical calculation of the steel cylinder, analysis model is established and the highest first pouring height is got. To ensure construction safety, casting speed can be from slow to fast and we can place level or toroidal support at appropriate placement of the steel cylinder. Moreover, test was done and the results show that the wall is in good condition, and the strength and stiffness satisfy the design requirements.

Abstract: In order to solve the problems of the pavement delamination or slip caused by the failures of waterproof adhesive layer or anti-corrosion coating, the epoxy zinc-rich paint, the epoxy clear water paint and epoxy asphalt adhesive material with good performance was selected for the roughness-adhesive force test, tensile test under different temperatures and corrosion resistance test. The optimal anti-corrosion layer and adhesive layer were selected to increase the service life of the steel deck pavement. The test results show that: When the steel roughness is 60μm, the anti-corrosion material has the highest adhesive strength with the steel plate. Both the epoxy zinc-rich paint and the epoxy water paint have high adhesive strengths with the steel plate at room temperature. But at low temperature, the adhesion performance of the epoxy water paint is significantly better than that of the epoxy zinc-rich paint. At 70 °C, the adhesive strengths of both the epoxy water paint and epoxy zinc-rich paint adhesive system greatly decrease. The destruction morphology shows the opening of the adhesive layer. The specialized anti-corrosion coating must be brushed on the steel deck.

Abstract: This paper mechanically applies the thought of recursive hierarchical structure in analytic hierarchy process, by means of fuzzy mathematics, with the investigation, analysis, induction, the fuzzy relation matrix has been found, at the same time, the assignment weight of index is merged into that. Then the integrated condition assessment results of bridge are gained finally. This method greatly reduces the happening of ill-considering the influencing factors, make the results more real, specific and comprehensive, avoid effectively great loss which is caused by the defects of safety and service performance.

Abstract: 6m arch board used as test object, this paper introduces the arch in different level of load board cracks, development and production of plastic hinge until the whole process for all the damage simulation numerical simulation analysis then compared with experimental results and analysis of increased with load crack distribution, which can be used to understand the similar in service work condition of the stone bridge.

Abstract: This paper is based on fracture mechanics to calculate the arch bridge crack spacing circle and the stress intensity factor. Then the relation between the cracks spacing limit problem is calculated. And stress intensity factor relations under the same crack length and the same pull force is discussed. Finally the analysis shows that the height of the fracture cracks into the crack width as the impact factor is feasible.

Abstract: In this paper, it is on the basis of gaining the main influence factors of durability for in-service bridge, using recursive hierarchical structure of analytic hierarchy process, constructing the assessment models about durability for in-service bridge in bottom, middle and top levels, combining with weight modify technology and fuzzy mathematics theory, the assessment results durability state is gained finally. It can discriminate using actuality of bridge effectively, and it has been a good guide for maintenance of bridge by practical test.

Abstract: Expansion joint of a bridge is a weak part of structure, it leads to early structure destroy and reduces the bridge life. The paper put forward a new type of Jointless Bridge --- Semi–Integral Abutment Jointless Bridge, and its theoretical model was built. An engineering of four spans 100m length Prestressed Concrete Semi–Integral Abutment Jointless Bridge was analyzed, and results that its mechanical performance is so excellent that it should be wide applied in bridge engineering.