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An approach to predicting the vibration responses of a bridge and analyzing the wave propagation characteristics along the bridge is proposed based on the waveguide finite element (WFE) method. For verification, a field vibration test was performed on a 30m-long simply supported box-girder on the fourth line of Guangzhou Metro in China. The numerical results were shown to agree well with the test results, demonstrating the accuracy of the proposed approach. The advantages of the WFE approach are discussed by comparing the WFE with finite element (FE) analyses. The dispersion characteristics and mode shapes of waves propagating in the box-girder are calculated by using the WFE method, from which the dominant wave modes corresponding to the peaks of the medium- and high-frequency train-induced vibrations are identified. A vibration reduction measure is considered. Both the test and numerical results show that the medium- and high-frequency vibrations of the box-girder are predominately in the 1/3 octave center frequency range of 63–100Hz with maximum occurring at the center frequency of 80Hz. The WFE method has higher computational efficiency and requires smaller storage space than the FE counterpart, but provides similar predictions as the latter. In total, there are 14 wave modes propagating in the box-girder below 200Hz. The G1, A1 and D2 wave modes are the dominant wave modes generating vibration velocity peaks on the top, bottom and flange slabs, respectively. Adding a middle web slab to the center of the cross-section is an effective way to mitigate the vibration of the box-girder bridge.

In order to predict more accurately the structural vibration and noise of elevated tracks induced by moving trains, a new prediction method based on the scaled model test is proposed in this paper. A 32-m simply supported box girder bridge used in the Beijing–Shanghai high-speed railway is selected as the prototype for designing and constructing a scaled model test with 10:1 geometric similarity ratio. Both experimental tests and finite element analyses were carried out to verify the similarity relationship between the model and prototype. The test result shows that the scaled model can predict the structural vibration and noise of the prototype, as long as the similarity constants between the prototype and scaled model are correctively determined. Furthermore, a standard finite element analysis model for the scaled model is built. Based on the sensitivity analysis, the model parameters for finite element analysis are updated by minimizing the errors between the measured and calculated modes. The computational results show that the updated model based on the local parameters partitioning works best, and the precision of the modal frequency calculated is noticeably improved after updating, with the average relative error reduced from 5.46% to 3.09%, and the difference of the peak values reduced from $0.358\times 10^3$m/s² to $0.189\times 10^3$m/s². The calculated dynamic response of the finite element model after updating is basically in line with experimental results, indicating that the updated model can better reflect the dynamic properties of the scaled box girder model. The updated finite element model is useful both for verification with the model test result and for reliable prediction of the dynamic characteristics of the prototype.

Fly swallow type arch bridge is now increasingly accepted, because it has the advantages of spectacular shape, large span ability, high bearing capacity, no-thrust arch structure, strong adaptation ability of foundation and etc. But in the construction process, there is error between design and construction work, which results in abnormal force performance of the structure, then lead to the safety of the bridge. With the fly swallow type concrete-filled steel tube arch bridge of Shenzhen Bay as the engineering background, the space mechanical characteristics of the arch bridge were analyzed through the finite element method, which evaluate the static and dynamic characteristics of the structure and the structural stability of construction process as well as the finished bridge. The calculation results and analysis show that the main arch ribs and side spans section can satisfy the requirements of bearing capacity of the structure. As a result, the static and dynamic performances of the arch bridge structure are good, which meet the design specification requirements. Fly swallow type arch bridge embodies the times flavors of modern bridge, it provides new ideas for large span curve special-shaped combination arch bridge.

In optimization of the box girder of bridge cranes, dimensions from the mid-span section, are common choices of the design variables, assuming that the box girder is a beam with constant sectional dimensions and that mechanical characteristics along the span remain unchanged. This assumption is limited in light weight design of crane structures since mechanical characteristics of the box girder vary substantially along the bridge span. To arrive at an even lighter design of the box girder, dimensions of the mid-span section, the end-span section and the length of the sloping segment of the girder are selected as design variables and a mathematical model is established for optimization. The limit-state design method is adopted and the centered differential evolution (CDE) algorithm is employed in solving the problem. For comparison a model based on design variables only from the mid-span section is built and analyzed using identical methods. The comparison points out that the multi-sectioned model can achieve a design of the box girder much lighter than the constant-sectioned model do while complying with instructions of design manuals.