It's a common practice to drill holes on one side of the bridge for drainage.
The main principle of doing this is to drain the rainwater and other liquids accumulated on the bridge surface through these drainage holes, so as to avoid damage to the bridge structure caused by water accumulation. The accumulated water may penetrate into the interior of the bridge, causing the building materials such as concrete to be eroded, or freezing and expanding in cold weather, which may lead to problems like cracks in the bridge. The drainage holes can guide the water to the appropriate drainage systems under the bridge or directly discharge it to the ground and other locations.
When drilling holes, it should be noted that the size, quantity and location of the holes should be determined according to the bridge's design and the actual drainage requirements. If the holes are too large, they may affect the structural strength of the bridge, while if they are too small, it will lead to poor drainage. Meanwhile, the location of the holes is also crucial, which should ensure that the accumulated water on the bridge surface can be effectively collected. Moreover, during the drilling process, damage to other parts of the bridge body (such as steel bars, etc.) should be avoided.
