近海T形 ?桥上部结构 ?端波浪作用试验

Extreme waves generated by hurricanes, as one of the most critical disasters that threatens the safety of bridge structures, have damaged many low-lying coastal bridges along the Gulf of Mexico. Thus, exploring the mechanism of typhoon waves acting on bridge superstructures is significantly important to develop a method to calculate wave forces. Periodic focused waves were employed as incident waves to investigate the effect of wave forces on bridge superstructures considering the spectral characteristics of extreme typhoon waves. A set of model tests with different maximum amplitudes, peak frequencies, and clearances were conducted. The specimen was designed following the Froude criterion on a 1:25 scale using a prototype of a T-girder bridge. The horizontal and vertical forces acting on the T-girder bridge with different clearances were measured in a wave flume. Consequently, periodic focused waves, with an appropriate period, are adequate to avoid the pollution of the incident wave caused by re-reflection, which guarantees the credibility of the test results. The low-frequency quasi-static and high-frequency slamming forces are the two components of wave forces. The peak value of the slamming force typically appears in the initial stage of wave water contact with the bridge deck. In general, the force of a wave increases with its amplitude. However, an apparent non-monotonic trend can be observed between the force and amplitude of a wave; thus, wave forces acting on the T-girder bridge first decrease and subsequently increase with changes in clearance. At a peak frequency of 0.4 Hz, a large-amplitude focused wave generates maximum wave forces on the bridge with a clearance in the range of 2.0-3.0 cm. A simple method was developed to calculate wave forces based on the experimental data, thereby providing a reference for bridge design.