Remote Methods of Underwater Inspection of Bridge Structures

摘要

A portable trailer mounted bridge scour inspector was developed and tested under211u001eflood conditions for inspecting bridge scour in the vicinity of piers from the 211u001ebridge deck. The bridge scour inspector features a remotely controlled arm to 211u001edeploy a sonar probe in the water from a vehicle located on the bridge deck. The 211u001earm can be fixed in a cross section mode to take cross sections immediately 211u001eupstream and downstream of a bridge or it can be maneuvered in the vicinity of 211u001epiers including some distance under the bridge deck to inspect for deep local 211u001escour holes. Two servo motors constantly adjust the orientation of the sonar 211u001eprobe to maintain a vertical beam. A mechanical positioning system tracks the X, 211u001eY, Z coordinates of the sonar probe wherever it is in the water relative to some 211u001ereference location on the bridge deck. The bridge scour inspector was field 211u001etested under low water condition in Texas and was field tested under extreme 211u001eflood conditions in Georgia during the 1994 Tropical Storm Alberta flooding. 211u001eLimitations of the bridge scour inspector include: the max distance of 15 meters 211u001e(50 feet) that the arm can be extended below the bridge deck to reach water, a 211u001eminimum distance of 4.5 meters (15 feet) needed to avoid total submergence and 211u001epossible malfunction of servo motor controls, and operation difficulties on truss 211u001etype bridges because the arm must be retracted each time it passes an elevated 211u001eobstruction. It is a viable bridge scour inspection device for many ridges during 211u001eextreme flow conditions when it is too dangerous to put a boat in the water.