With regular triangular prisms of different characteristic widths as vibrators, this paper carries out the flow-induced vibration test on regular triangular prism, discusses the flow-induced vibration performance of regular triangular prism, and discloses the effect of characteristic width on vibration response and energy transformation. The test results show that the galloping of the column is divided into hard galloping and self-excited galloping. Greater characteristic width leads to higher response-amplitude ratio and lower vibration-starting velocity. In addition, increasing the characteristic width enables the regular triangular prism to gallop against higher maximum damping ratio, thereby elevating the optimal power generation damping ratio. Higher optimal power generation damping ratio in turn improves the unit capacity and energy transformation efficiency of flow-induced vibration power generators.
Due to the unreasonable allocation method, the bridge maintenance funds in Shaanxi Province can not provide maximum value. In this study, we used different functions to fit the actual technical condition data of bridges in Shaanxi in recent years, and through comparison, the exponential model with the best fitting effect was selected as the deterioration model for the bridge and its parts. Based on this, the deterioration characteristics of the bridge and its parts were further analyzed. Based on the results of the analysis, the deterioration coefficients (A) applicable to the bridge and its parts in Shaanxi Province, considering the ages and service environments of the bridges, are summarized. The concept of disease transmission is proposed based on the different deterioration characteristics of the bridge parts. The deck pavement, expansion joints, and bearings were identified as the key components of disease transmission, and the disease transmission paths were built with them as the center. Considering the technical benefits, economic benefits, and diseases of the key components of bridge maintenance, the second-generation nondominated sorting genetic algorithm (NSGA-II) was used to calculate the maintenance fund allocation scheme in the bridge network maintenance decision under different budget–demand ratios. The findings show that there are significant differences in the deterioration rates of the deck systems, superstructures, and substructures, as well as of the overall bridges, in Northern Shaanxi, Central Shaanxi (Guanzhong region), and Southern Shaanxi. Diseases of the bridge deck pavement, expansion joints, and bearings can lead to diseases of other elements. Compared with the traditional method of allocating maintenance funds based on the principle of prioritizing bridges with the worst technical conditions, the economic condition growth rates of the results of this study were 94.2%, 106.2%, 92.9%, and 62.8% for budget–demand ratios of 20%, 40%, 60%, and 80% of the maintenance funds, respectively. The proposed method for allocating bridge maintenance funds provides a reference for the subsequent development of bridge maintenance decision specifications.
In order to accurately calculate the sunshine-induced temperature effect of an ultra-high bridge pylon, a refined numerical simulation model for the 3D bridge temperature field was established based on the proposed automatic sunshine shadow recognition method and pylon-height-related convection modification method. A suspension bridge H-shaped pylon with a height of 280 m was taken as an example, and the temperature field and corresponding thermal stress and deformation were calculated under typical meteorological conditions in spring, summer, autumn, and winter. The results show that the maximum temperature differences between the outer surfaces of the pylon can reach 19 °C and 16 °C for north–south walls and east–west walls, respectively, and exceed the recommended value of ±5 °C in the Chinese Specification. The maximum displacements can reach 370 mm and 110 mm at the top of the bridge pylon in the longitudinal and transverse directions of the bridge, respectively. After the modification of the convective coefficient of the outer surfaces with different wind speeds at different pylon heights, the temperature gradually decreased from the top to the bottom of the pylon, with a temperature difference of 8 °C. The significant influence of the sunshine shadow was shown on the temperature field and temperature effect of the bridge pylon. By considering the shadow effect, the maximum temperature difference can reach 12 °C between adjacent sunlit and shaded areas and can reach 14 °C between two pylon columns. A significant mutation of thermal stress existed in the shaded area, and the maximum stress could be reduced by 13 MPa compared with the adjacent sunlit area. Obvious asynchronous deformation was shown between two pylon columns, and the maximum asynchronous displacement at the top of the pylon can reach 18 mm and 45 mm in the longitudinal and transverse directions, respectively.
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