Experimental analysis of scour depth around eccentric circular piers under constant flow conditions

Abstract

Scouring by the flow of water in rivers and streams has the greatest impact on alluvial materials beds, but solid rock can also be vulnerable in some cases in mountains stretches of the river. Bridge collapses are a widespread occurrence that causes fatalities, property damage, and halts transportation due to this hydraulic phenomenon called scour. As a result, bridge designers and technician must increasingly understand how soil, water flow, and bridge structures interact. Mostly in the growing cities around the world, traffic load increases, rapidly and more bridges are needed beside the existing one to connect roads and manage traffic. In recent years, researchers have been also studying how to use the natural process of scour to their advantage. They have explored the idea of dredging, which is a method that allows water to naturally move sediments to the sides of channels, without using machines. This process can reduce costs and environmental impact, while still helping to maintain water channels. This study looks into how bridge piers can affect the way water flows and causes erosion around them, especially when the piers are placed in different positions. Understanding how deep the water can dig around these piers, called scour depth, is important to keep bridges safe. The research focuses on how different pier layouts affect the movement of water and erosion. In a controlled environment, we studied how the water erodes and deposits sediment around both front piers and eccentric center piers over time. A total of 24 experiments were carried out using two identical circular bridge piers, each 7 cm in diameter. The distance between the upstream and off-center piers was kept the same, set at 5.185 times the diameter of pier. During the experiments, a steady water flow rate of 30 liters per second was maintained to ensure clear water conditions. The experiments lasted between 2.5 to 10 hours, depending on the specific setup, to observe how the scour changed over time. Various measurements, including the depth, width, length, area, and volume of the scour, were carefully calculated using the data from the experiments. The results were then carefully analysed to determine the most optimal eccentricity arrangement, which is an important issue for bridge designers and dredging professionals looking to improve their procedures. In conclusion, this study investigates the complex dynamics of scouring in connection to bridge design and sediment control. It highlights the potential benefits of using natural scouring processes to relocate sediments gives valuable insights for specialists in this field. Through experimental methods and in-depth research allow for a better understanding of how bridge structures interact with their aquatic environments, resulting in the development of more durable and sustainable infrastructure solutions.