Applied Mechanics and Materials Vols. 178-181

Abstract: It is critical to choose a reasonable closure scheme for the construction or post- construction state of multiple large-span prestressed continuous beam bridges. The feasible closure schemes were analyzed and evaluated. The optimum closure scheme analysis method was proposed. Take Wei river bridge for instance, by deformation, internal force and stress comparison, and construction roubustness analysis, the optimum closure scheme is set down to ensure the girder close smoothly with reasonable internal force.

Abstract: The degradation model of reinforced concrete under general atmospheric environment was summarized. The life-cycle reliability assessment method of existing concrete beam bridges was proposed. The probability model of the life cycle resistance and load effect were established. The time-dependent reliability analysis program was compiled. The engineering application shows that the life-cycle reliability assessment method introducing the material degradation model can predict the remaining life of existing bridges scientifically, and ensure safe operation of bridges.

Abstract: Simply supported hollow slab bridge is widely used in highway network of China. Under overload vehicles, the concrete hinges of such bride are easily damaged, which usually causes single slab bearing and tremendously reduces the bridge’s load capacity. It is necessary to take some reinforcement measures to enhance the carrying capacity of such impaired bridge for traffic safety. In this paper, a field reinforcement experiment of an actual hollow slab bridge, which has experienced a destructive test with its transverse connections seriously damaged, was performed by applying external transverse and longitudinal prestress to it. The strengthening scheme adopted in this experiment was detailed. By means of static truck load test, the variation of deflections of the bridge before and after strengthening was obtained. The test results showed that the proposed strengthening method can effectively enhance the damaged hollow slab bridge’s transverse stiffness and improve its bearing capacity.

Abstract: In this paper, an experiment is carried out on compressive elastic modulus, shear modulus, silicon fat consistency and peel strength of synthetic rubber bearing and cold type natural rubber bearing produced in Shanghai Rubber Factory under low temperature condition. The experiment reveals the mechanical property of rubber bearing and change law of cooling temperature difference which offers reference and guidance for the selection of rubber bearing products under low temperature condition.

Abstract: By building a finite element model of a special-shaped arch bridge, this paper discusses the effects of the changes of the geometric shape, and the skewed angle of the girder and arch on the dynamic characteristics. During the free vibration characteristics analysis, changes in the rise-span ratio had a relatively significant impact on the special-shaped arch bridge’s free vibration frequency since the basic frequency would increase as the rise-span ratio decreased. Changes to the rise-span ratio had a relatively minimal effect on the in-plane vibration status, while it had a significant effect on the out-plane vibration status. This difference is because at the in-plane, the curved structure receives a significant amount of axial force, while at the out-plane, the transverse load response is stronger.

Abstract: In China a large number of bridges built in 1960s and 1970s are still in operation. They went through several decades of intense heat and cold winter, water scouring, and accelerated load-increasing, which will lead to the deterioration of the structure. They are in the need of maintenance, reinforcement and transformation. The bridge assessment, maintenance, reinforcement and strengthening for the safety and reliability of existing bridges had attracted the attention of researchers. It’s essential to reinforce the old bridges with appropriate designs and construction technologies to improve its load-carrying capacity and extend the service life to meet the requirements of the current transportation. This paper first introduced China’s current situation and existing problems of the bridges. Then the strengthening methods and techniques for the existing damaged bridges are presented. The conclusions and future prospects are finally given.

Abstract: The author took a rigid frame-continuous beam bridge for example, analyzed by means of plane finite element and space finite element methods. In the space model, corrugated pipes were built in order to consider the weaken effects to cross-sections. Aimed at the least well stage which is after prestressing and before grouting, spatial stresses were indicated. Final results indicate exceeded transverse tensile stresses caused by radial forces are the most important factor which led to bursting cracks.

Abstract: Considering the transformation of the system and the increasing of the load in the construction process of long-span arch bridge, combining with the definite engineering example and calculating the construction process of arch bridge by using finite element method,focusing on the analysis of deformation and stress of arch bridge under the effect of shrinkage and creep in the process of construction.

Abstract: Based on the conclusion of shear stiffness experiment of vertical segmental joint in cantilever casting concrete bridges (CCCB), finite element models (FEM) study was conducted to assess the shear stiffness of sloping segmental joints in this paper. Through the comparison of calculating relative vertical displacement at joint between vertical and sloping joint, it can be educed that the shear stiffness of slope joint between 5º ~15º increasing as the increasing of slope angle is consistently higher than vertical joint.

Abstract: Self-anchored suspension bridge is a self-balancing system by anchored the main cable at each end of main girder. With complicated configuration and important rule of transferring tension in main cable to main girder, the anchorage region is one of the most critical issues during designing a self-anchored suspension bridge. It is impossible to fully understand the mechanical behavior only by spatial beam and column model but spatial refined model. Because the behavior of anchorage region is greatly influenced by its boundary condition, in this paper, reasonable length of main girder in calculation model is discussed based on the spatial refined model. The mechanical behavior of initial anchorage structure is calculated. A modified anchorage configuration is proposed according to the stresses distribution of anchorage zone. Calculation results show the modified anchorage configuration can make the force transferring smoothly and decrease the stresses of anchorage structure, and it can be referenced to similar bridges.