Development and Application of Real-time Bridge Scour Monitoring System ()
1. Introduction
Traditional scour research relied mostly on lab simulation tests. The simulations posed great difficulties in providing reliable data as the materials and variables could not be consistent or controlled. In most simulations, insignificant factors were ignored to concentrate on the major factors. The simulations were limited to measuring the maximum scour bed changes. For a more efficient and in-depth study in scour research, a real-time scour measurement system was needed.
Despite the critical need for a real-time scour measurement system, the limitations of technology in a difficult environment for scour measurement have prevented the advancement of a real-time scour measurement system. Since scour bed changes in rivers are created during high water flood conditions and rapid water movements that cause muddy water mixtures, safely obtaining scour bed measurements in real time has been impossible. The measurements are therefore taken after flood conditions, or during calm tidal waves for oceanic bridges. These measurements are taken well after the most violent scour bed changes, making the data virtually useless in monitoring scour bed movement.
The purpose of this research was to address these issues by developing a scour measurement system that is unmanned, remote-controlled, and performed in realtime. The research was then tested in oceanic bridges to prove its efficiency and reliability. By remotely obtaining and analyzing data sent in real time, monitoring scour bed changes, water depth changes, and scour behavior became a reality.
2. Development of the Real-Time Bridge Scouring Data Acquisition & Monitoring System
The real-time bridge souring data acquisition & monitoring system was developed to satisfy the ultimate goal of analyzing the actual quantitative bridge scouring measurements in bridge scour research. By combining a bridge scouring data acquisition system and a communication system, monitoring the bridge scouring data in real time brought a new dimension in bridge scour research.
2.1. Developmental Conditions for the Real-Time Bridge Scouring Data Acquisition & Monitoring System
In order for a new system to be developed, the system must not only address the current problems, but also reflect the environmental conditions of the installation site at the same time. The basis of the research and field study can be seen from the following developmental conditions of the system:
1) The system must be able to continuously monitor the bridge scouring data under any harsh environmental conditions.
2) The system must be able to evaluate bridge scouring data from an accurate plane.
3) The monitoring must be done in real-time.
4) The system must be universal, used in rivers to oceans.
5) The system must contribute to the safety of bridges by providing a direction in bridge const-ruction.
To address the conditions above, the following measurements were taken. First, an automated bridge scouring sensor located above the water can be used to acquire data under any conditions, unmanned. Second, a remote data inquiry and controller can provide data from an accurate plane. Third, the real-time data can be acquired from an automated system that can provide a simpler and a smoother acquisition process. Fourth, a new scouring sensor (SM200) that was developed by using supersonic wave distance sensors is used anywhere, from rivers to oceans. Fifth, the real-time data can be stored in a database for analysis and instant monitoring of scouring data for bridge safety.
2.2. Field System Composition
Figure 1 is a diagram of the field system concept. The field system is composed of four major elements: the electrical power supply source, data collection equipment, scour measuring equipment, and the data communication equipment. The power source is run by both battery and solar power. Solar power is used and stored during the daytime, and the charged battery is used during the night time. The heart of the system is the data logger, a small computer that processes the data acquired in real-time from the sensors. The most appropriate and safe sensor