Advanced Materials Research Vols. 446-449

Abstract: Suspension line Old bridges are rare exception in our country. Researching this kind’s old bridge is very interest to the bridge scholar. Zhejiang Yucheng bridge, located in Shengzhou of Shaoxing city, it is a typical suspension line bridge structure; it has been 150 years of history. Despite the impact of flash floods for so far, but, at present, it is still good for normal used, only local stone blocked off. Based on this old suspension line bridge, measuring the bridge size data, using the finite element software ANSYS for the modal analysis, the calculation results show that the fundamental frequency as 19.650Hz, and ten vibration modes and frequency bands can be obtained. In the end, about the reinforced methods are study, such as foreign adhesive steel and carbon fiber reinforced polymer (CFRP), pressure grouting way on the gap and so on. All of this may be help for old suspension line bridges research and reinforced.

Abstract: When a fire occurs, the strength of the concrete structure deteriorates due to temperature rise under the condition of constant load. The deterioration in strength causes the change in axial load ratio, so the structure is deformed. In this study, loaded heating test of concrete lining was conducted to realize the condition of an actual fire outbreak in a tunnel where heating and loading affect the structure simultaneously. The shape of the specimens was planned in compliance with the standard for small scale test prescribed in the EFNARC and 24 MPa, 40 MPa and 50MPa were used to analyze the thermal properties associated with different concrete strengths. Constant loading condition was provided based on the load ratios equivalent to 20 % and 40 % of the sectional stress in the concrete and the MHC fire scenario was selected to realize the thermal impact on the concrete by rapid temperature rise. Under each load ratio, more cracks were observed in higher strength and spalling occurred in 50MPa. In terms of fire damage range, 50mm points from heated surface of the 200mm lining did not satisfy the ITA standard for concrete lining upon a fire.

Abstract: In this paper, the situation of the midspan deflection of the span continuous rigid frame bridge is described, and the cause of the deflection is explained. It may be caused by the problem of the rigidity. Then the ANSYS is used to conduct analysis. The deflection of the biggest cantilever of the rigid frame bridge is the controlled target, and the optimizing design of the Sutong bridge is conducted. A meaningful result is obtained, and it provides a basis of the choice of the height of beams.

Abstract: In the CFST arch bridge construction process, for the reasons of arch axis deviation as prefabricated or constructed, the bearing capacity of arch-rib decreased. This paper considers material and geometric non-linear double factors, calculates the arch-rib ultimate bearing capacity of a CFST arch/continuous beam bridge with defects of arch axis deviation and steel yield stress decrease because of heat treatment, obtain the influence of defects to arch bearing capacity.

Abstract: In this paper, a continuous beam arch bridge Dukeng bridge was introduced. Its construction process and its construction monitoring were discussed. In the construction process, the elevations of the box girders measured were closer to the values theoretical calculated. Though construction monitoring, although there were some construction errors, they can be timely adjusted and rectified and the main beam was ensure to smoothly closure.

Abstract: Excessive longitudinal displacement of the girder would emerge in floating system bridge subject to vehicle braking force because of non-restraint in longitudinal direction of the bridge. To reduce it, viscous dampers are set up in longitudinal direction between the girder and the tower of floating system bridge, and the influence matrix method is applied to determine the optimal parameters of viscous dampers. The analysis results of Pingsheng Bridge show that the longitudinal displacement of the girder is relatively large for floating system bridge, and it can be effectively controlled by viscous dampers with optimal parameters obtained by influence matrix method.

Abstract: The damage analysis based on the modal parameters usually need to compare the test data with the computed data by theoretical analysis. In bridge structure damage analysis, it is impossible that the sensors are set at every node. So the test data need to be extended to every node by using interpolation technology. In the paper, three interpolation methods, cubic interpolation method, cubic spline interpolation method and sinc interpolation method, are introduced. Their applications in bridge structure damage analysis are discussed. The experiment results show that the best interpolation method is cubic spline interpolation method. Using the data processed by interpolation technology can well obtain the damage location of bridge.

Abstract: In view of the problem of concrete crack in the period of construction, this paper introduces the cause and the forming mechanism of crack in thin-walled concrete structure and points out that the difference between the inside and outside temperature at early stage and the basic difference of the temperature at later stage are considered as the main factors influencing the phenomena. This paper puts forward the application of pipe cooling which is used in the mass concrete to the thin-walled concrete structure. In doing so, the difference of the internal and surface temperature is reduced and the appearance of cracking is avoided. Under the basic theories of temperature field and stress field of concrete, the 3-D FEM with the numerical algorithm of pipe cooling is adopted to simulate the thermal field and stresses field of concrete aqueduct during construction and the result shows that good effect of temperature control and crack prevention is achieved in thin-walled concrete structure. At the same time, water cooling pipe has many merits including simple operation, easy adjustment, high adaptability, and low cost

Abstract: In order to analyze the response and influencing factors from vehicle-bridge coupled vibration between curved continuous rigid frame bridge and whole vehicle model of 7 degrees of freedom, a spatial numerical analysis method of vehicle-bridge coupled vibration caused by bridge deck roughness was proposed. According to power spectrum density advised by GB/T 7031-2005, bridge deck roughness was simulated by the application of Fourier reverse transform. Because of delay of front and rear axles and correlation between left and right wheels, the roughness sequence of each wheel was obtained by the frequency response function solved by means of random vibration theory. The samples were taken as the input disturbances, rules of vehicle-bridge coupled vibration response under different grades of bridge deck were obtained using the finite element software ANSYS. Analysis results indicate that the value of dynamic coefficients of displacement and torsional angle increase sharply along with the grade increase of bridge deck roughness, and accurate simulation of bridge deck roughness is crucial for analyzing and evaluating the impact of vehicles on the bridge.

Abstract: Main cables of self-anchored suspension bridge are anchored at each end of main girder, thus producing a self-balancing system. In order to transfer the cable force to main girder safely and smoothly, the anchorage region is one of the most critical issues in design of a self-anchored suspension bridge. It is hard to fully understand the mechanical behavior only by spatial beam and column model, so a 3D shell finite element model is established to overcome the limitation of spatial beam and column model. The mechanical behavior of initial designed anchorage structure is then analyzed and a modified anchorage fabrication is proposed to improve the stress distribution. Analysis results show that: the modified anchorage system effectively reduces the stress level of anchorage structure and enhances the efficiency of anchorage structure.