Applied Mechanics and Materials Vols. 90-93

Abstract: In order to assess the service states of the permanent prestress of transverse prestressing bundle for the Xiangjiang Yinpenling Bridge (XYB), the permanent prestress values are measured. Appearance census of the diseases of transverse prestressing bundles for the cable-stayed part, the east and west incremental launching girder parts of the XYB are carried out. Three transverse prestressing bundles of the most serious corrosion are investigated by windowing damage inspection. The measured results and the analysis of the permanent prestress for the XYB show that the average permanent prestress of the three transverse prestressing bundles is about 300MPa to 550MPa, which do not meet the requirements of the design tension stress. It suggests that the appropriate treatment measures should be taken.

Abstract: Harp shaped cable-stayed bridges without backstays are popular due to their beautiful and unique styles; they employ leaning tower columns to balance the constant and movable loads on the decks and are not provided with backstays, so they are beyond the traditional bridge design philosophy. In this paper, we discussed the reasonable structure of the main girder of Changsha Hongshan Bridge – a harp shaped cable-stayed bridge without backstays through changing the design parameters of the main girder in respect of design so as to provide important reference for design of this kind of bridges, and the research mainly related to such aspects as the structure selection for and section design of the main girder, the influence of overweight of main girder on the force on the structure, the length of non-cable area of the main girder, the span of auxiliary hole, etc.

Abstract: The landscape is very important for the overpasses and other bridges built in the city. Not only should it be integration with land, sky and surrounding scenery, but also reflects the city's humanities content and historical background. Structures with landscape features, of which the forces are different from the normal structures, often have rather special characteristics. To ensure the safety of these structures, the test is often needed, and of course a lot of test equipments, sites and costs etc are required.Without the need of test sites, testing instrument, and test model fabricating, the simulation analysis, which could get better effect than actual model test in some cases, has been extensively applied in lots of industries, such as machinery manufacture, aerospace, civil engineering, etc. Be great reference value for the design of the bridge, the simulation process and relevant conclusions of a curve pier in Hefei (the flower city in China) are described in this paper.

Abstract: Tension rocker bearing (TRB) cables installed at auxiliary piers were critical members to sustain the structural system in a prestressed concrete cable-stayed bridge. Once these cables fractured or broken, its structural system would be transferred. Based on diseases caused by fracture of TRB cables in Yonghe Bridge, corresponding maintenance or strengthening measures were described in detail. These measures included replacement of TRB cables, strengthening of the closure segment of main girder at each side span, and adjustment of stay cable forces. Monitoring results showed that, its structural system was finally and completely rehabilitated, and the safety factor of new TRB cables is enough under the most unfavorable load combination. Moreover, the line shape of main girder and the inclined displacement at the top of each pylon were improved effectively. Thus, Yonghe Bridge accumulated some valuable experience for maintenance or strengthening of existing prestressed concrete cable-stayed bridges, and also made a useful exploration.

Abstract: A main span of 500m of rock tunnel anchor steel truss single span suspension bridge, Structure of the tower across the bridge, cross a large, soft, weak damping characteristics, and the bridge site at the complex terrain, the actual wind field is more disordered, so be checking the stability of the structure of the wind. Wind stability checking showed that the torsional flutter and torsional flutter separated flow is less than the critical velocity self-excited vibration of the main beam test wind speed, wind does not meet safety requirements. Therefore, an additional level of rigidity with the wind the cable, set the cross-slope index, increased truss width, the main cable using a single triangle boom, the use of space for the main cable, etc. to increase the stability of the bridge on wind resistance. After considering the construction of economic and structural terms, the final choice of the main cable space, the top cable from 1m, the main tower for the A-type tower program. The study on the stability of the same type of calculation of the bridge with the reference wind.

Abstract: Yongjiang Bridge in Ningbo is a double-tower-connected cable-stayed bridge which new structure system is very complex and the first one in China. In order to roundly investigate the structural behavior of the double-tower-connected, 3:40 scaled-down model test and space finite element analysis were presented. Test objective, model design principle, the ratio of similarity, test cases, loading method and the strain test point arrangement were introduced in detail. By comparison of two unfavorable test cases, most test data were quite agreeable with the theoretical data, which verified the design concept. The results indicate that the whole resistant behavior is well and the structure is safe and reliable.

Abstract: Combined with the application of high-performance concrete in bridge engineering, the construction technics of pretensioned prestressed high-strength concrete (PPHC) hollow slabs with new section is summarized. The qualities of concrete in C80 strength grade are statistically analyzed based on the precast of 75 PPHC hollow slabs for two bridges. The results show that it is reliable to precast PPHC hollow slabs for bridge construction.

Abstract: Based on the experimental investigation of quasi-static test of 6 AAC block walls and obtain the load-displacement experimental results, the deformation behavior and dissipative capacity of the walls due to different height to width ratios and vertical pressing stresses are studied and analyzed, the comparisons and analyses with other block walls’ deformation behavior are also carried out. The results indicate that AAC block walls’ dissipative capacity is directly proportional with vertical pressing stresses and the deformation behavior is otherwise, the diversification of height to width ratios can change the breaking form of block walls and affect on ductility and dissipative capacity. The ductility of AAC block walls is better than other block walls.

Abstract: Through theoretical calculation, systemic analysis of dynamic performance of the 64m single and double line railway steel truss bridges on the expanding condition and conventional condition. Contrast and analysis the main dynamic performance parameters of bridges on the two kinds of operating condition. In 64m steel truss bridges of Shuozhou-Huanghuagang Railway application practice proves that on expanding heavy-load condition, the main dynamic performance parameters of bridges are slightly larger than conventional condition, but the variation law of vertical acceleration of mid-span is different.

Abstract: This paper studies the dynamic response and the impact factor of the concrete-filled steel tubular (CFST) arch bridge named Hejiang River Bridge under the moving vehicles. Research shows that the impact factor of CFST arch bridge at the vault and 1/4 arch rib is greatly influenced by the road surface roughness (RSR), and it is increased with the grade of RSR increases, meanwhile it is different at apiece section position of the arch bridge. The impact factor doesn't vary monotonically with the speed of vehicle, it appears the maximum when the speed of vehicle is between 20-25 km/h and 35-50 km/h, and the impact factors of different cross-sections are not just the same with the changing regularity of speed. Therefore, the dynamic characteristics of different structural components should be calculated in designing CFST arch bridge for discrepant dynamic characteristics of various constructional elements.