Seismic Study of Skew Bridge Supported on Laminated‐Rubber Bearings

Advances in Civil Engineering

et al. 2023

In this article, wrap rope connection device (WRCD), which considers the relative acceleration of piers and beam as a control variable, is proposed for improving the current situation of continuous girder bridges whose bearing force of a single pier is along the longitudinal direction and based on the synergy principle. The WRCD device, which meets the slow displacement requirements of temperature and vehicle load under normal operation, is implemented and used to improve the performance of the sliding bearing pier. During earthquakes, because of the amplification effect of the wrap rope, the instantaneous large stiffness state in the longitudinal force can be achieved. Based on the shaking table test of a typical continuous girder bridge for examining the performance of the WRCD during earthquakes, the dynamic characteristics, structural acceleration, displacement, and strain responses of the structure under different frequency spectra, and seismic input intensities are analyzed and the seismic reduction performance of the WRCD is demonstrated. This analysis demonstrated that, by activating WRCD, the ratio of the acceleration response of the fixed bearing pier to the sliding bearing pier increased from 10% to 57%; moreover, the force on each pier appeared more uniform. Furthermore, with an increase in the input intensity of the earthquake, the displacement of the primary beam and the seismic response of the fixed pier bottom considerably decreased and the synergy effect of each pier was more prominent. Under certain site conditions, the WRCD can effectively improve the synergy effect between the sliding bearing piers and fixed bearing pier; however, the improvement in the obtained result is directly associated with the seismic input characteristics. The design parameters of the WRCD should be determined as per different site conditions and the optimum application range of the WRCD.

Section: Counterweight Designmentioning

confidence: 99%

Seismic Reduction Performance of Wrap Rope Connection Devices for Continuous Girder Bridges

Liu

Advances in Civil Engineering

et al. 2023

“…e bridge pier of the model assumes stiffness equivalence [1,[13][14][15][16][17]. e section design of the bridge pier is strictly equivalent as per the bending stiffness, ignoring the torsional and axial stiffnesses.…”

Section: Shaking Table Testmentioning

confidence: 99%

Shaking Table Tests on Wrap Rope Connect Device for Continuous‐Beam Bridges with Different Pier Heights

Liu

Advances in Civil Engineering

et al. 2022

To investigate the cooperative and isolation effectiveness of the wrapped rope connect device (WRCD) on continuous-beam bridges with different pier heights, shaking table tests were conducted on a typical three-span continuous-beam bridge model. The model had additional pier stiffness and applied the WRCD. Two actual seismic waves with different spectral characteristics and multiple intensities were used for input ground motion. By examining the performance and measured structural response under various excitations, WRCD could effectively improve the overall cooperative effect of the model structure for a limited increase in the input seismic energy of the system. The acceleration ratio from the fixed pier top to the movable pier top increased from∼17% without the WRCD to∼32% with it. The strain-response ratio of the pier bottom decreased from its maximum of 24.8 times to 3.6 times after the device was applied. There is a specific relationship between the influence and the pier height of the structure, and the rules for high and low piers slightly differ. The movable and fixed ports can be coordinated by setting reasonable design parameters of the WRCD, which can be used for the seismic design of continuous-beam bridges with different pier heights.

“…By comparing 8 h of starting freezing to 16 h of complete freezing, the temperature gradient has a direct influence on the development speed and freezing depth of the freezing front (A2 and A3 and B2 and B3). When the temperature field distributions of the two freeze-thaw cycles are compared, it is discovered that the freeze-thaw cycle has little effect on the temperature field distribution of graded sands during freezing [17][18][19][20].…”

Section: Water Supply Systemmentioning

confidence: 99%

Frost Heaving Properties of Gravelly Soils in Alpine Seasonally Frozen Regions

Chen

Advances in Materials Science and Engineering

et al. 2022

To investigate the frost heaving properties of gravelly soil in alpine seasonally frozen regions and provide a foundation for the antifrost heaving design of the foundation tower in the Manzhouli 500 kV electrical transmission line. First, particle analysis and compaction tests were used to assess the basic characteristics of gravelly soil. Then, to investigate, a unidirectional freezing test of graded sand was performed to analyze the regularity and properties of the frozen process of graded sand. The test results demonstrate that the temperature gradient and the number of freeze-thaw cycles considerably affect the freezing of graded sand. The greater the temperature gradient and the number of freeze-thaw cycles, the greater the frost heave. In the freezing process, graded sand with zero fine-grain content exhibits obvious freezing shrinkage and thawing settlement. Still, the frost heave of sand is small. The frozen damage of graded sand is not caused by frost heaving deformation but by the deterioration of soil structure and the decrease of bearing capacity under hydrothermal coupling. Finally, experimental research is used to propose prevention and control measures for frost heave of power transmission and transformation projects.