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Test method of simulating erosion and fatigue load of prefabricated bridge joints
Published in Hiroshi Yokota, Dan M. Frangopol, Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations, 2021
The research object of this test is derived from the prefabricated concrete box girder bridge in actual engineering. The cross-section of box girder bridge (Lu et al., 2018) is a kind of closed thin-walled cross-section with large torsional rigidity and high cross-section efficiency; at the same time, its top and bottom plates are relatively large, which can effectively bear the positive and negative bending moments, and meet the needs of reinforcement and construction, so it is widely used in modern bridge construction. The prefabricated box girder bridge generally refers to the use of precast prestressed concrete box girder in the construction and then assembled on the site. The precast box girder is connected to each other along the two sides of the upper flange, and the joint (wet joint) between the flange is composed of the steel bars extended from the beam flange and web with prestressed steel bars and cast-in-place concrete, which forms an integrated whole with the box girders on both sides.
Steel Box-Girder Bridge Diseases Identification Based on Computer Vision System
Published in Nigel Powers, Dan M. Frangopol, Riadh Al-Mahaidi, Colin Caprani, Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges, 2018
Corrosion, coating spalling and fatigue cracking are major diseases in steel box-girder bridges, and these diseases may lead to deterioration of structure performance as well as the increasing risk of failure. At present, the corresponding manual detection methods are adopted for various diseases. For instance, manual visual inspection is widely accepted in steel corrosion and coating deterioration detection, while ultrasonic and magnetic particle inspection has become a common practice in detecting fatigue cracks. The major limitations of these traditional manual inspection are the hardness of digitization and standardization due to the detection and evaluation results of diseases depend on the experience of inspectors to a large extent. In addition, it is costly and unachievable in the long-term monitoring of diseases especially in the inaccessible regions.
Box girder bridges
Published in M.S. Cheung, W. Li, S.E. Chidiac, Finite Strip Analysis of Bridges, 1996
M.S. Cheung, W. Li, S.E. Chidiac
Box girder bridges are very popular for highways because of their high torsional rigidity and good appearance. However, the structural analysis of box girder bridges is a very difficult undertaking because of their complex deformation pattern and stress distribution, especially if the structure is continuous over intermediate supports and includes unsupported stiffening diaphragms. Although both the finite strip method and finite element method can be employed to analyze such bridges, the analysis cost is greater for the latter. In this chapter, the implementation of the finite strip procedure coupled with the flexibility approach is presented as an economical solution for the analysis of box girder bridges.
Numeric Study on the Critical Angle of Seismic Incidence for High-Speed Railway Bridges with Round-Ended Piers Based on the Fragility Method
Published in Structural Engineering International, 2023
Huijun Shen, Hehui Zheng, Feng Zhang, Linsong Chen
A three-span high-speed continuous girder railway bridge with round-ended piers is selected as an example in this study. The span of the bridge is (48 + 80 + 48) m, as recommended by Chinese criteria33–36 and widely used in China. Figure 2 shows the details of the bridge. As shown in Fig. 2, the superstructure of the bridge is a cast-in-place, non-uniform pre-stressed concrete box girder. The substructure consists of four solid reinforced concrete round-ended piers. The longitudinal rebar ratio of the middle and side piers is 0.87% and 0.55%, respectively, and the stirrup rebar ratio is 0.41% and 0.34%, respectively. The foundation at the bottom of the middle piers consists of 12 circular piles of diameter 1.25 m and length 57 m, the foundation at the bottom of the side piers consists of 12 circular piles of diameter 2 m and length 78 m. Spherical steel bearings are adopted for the bridge. The bearings on the top of pier #2 is longitudinally fixed, while the other bearings are longitudinally sliding. C50, C35, and C30 concrete are employed in constructing the girder, pier and pile foundations, respectively.
Bending characteristics of composite box girder considering all surfaces shear deformation based on Hamiltonian system
Published in Mechanics Based Design of Structures and Machines, 2023
Pengzhen Lu, Dengguo Li, Yijie Zhang, Yutao Zhou
Steel-concrete composite box girder is a new type of structure developed on the basis of steel structure, concrete structure and thin-walled box girder structure. The upper part is composed of a concrete slab and the lower part is a steel box girder. In order to ensure the common force of the two materials, the concrete slab and the steel box girder are connected by shear keys. The concrete slab bears the compressive stress of the beam body and the steel beam bears the tensile stress, giving full play to the mechanical properties of the two materials. Compared with reinforced concrete box girder, the steel-concrete composite box girder can reduce the weight of the structure, reduce the seismic effect, improve the ductility of the structure, increase the effective use of the structure, reduce the cost, and shorten the construction period. Compared with steel box girder, it can reduce the amount of steel used in the structure and increase the rigidity and stability of the structure (Soto et al. 2020; Fang et al. 2020; Zhou et al. 2019). Therefore, steel-concrete composite box girder is widely used in the construction of urban overpasses, viaducts and railway bridges. For example, the East China Sea Bridge in China, the Balduisntein Bridge in Germany, and the Imperial Bridge in Vienna, Austria all adopt the structural form of combined box girder.
Inconsistency recovery and assessment for crack data of steel box girders
Published in Structure and Infrastructure Engineering, 2023
Yihu Ma, Airong Chen, Benjin Wang
The steel box girder has been widely used in the construction of long-span bridges, while a large number of welded joints may lead to poor fatigue performance. The structural redundancy can often provide enough safety proof as the fatigue cracks mainly harm the serviceability of the bridge (Wang, Dong, Pan, & Ma, 2020), thus the steel box girder can be put into service with fatigue cracks and secondary diseases for part of the life cycle of the bridge. In that case, the studies on this issue should emphasise the crack behaviours in the entire fatigue process. As the experiments are often limited by the boundary conditions and applied loads, it is difficult to give a comprehensive view of the exact state of the realistic structure by referring to the life for one or several details only.