Portable Scour Monitoring Equipment (2004) / Chapter Skim
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Appendix A: Users Manual
Appendix A: Users Manual
Pages 51-70
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From page 51... ...
A-1 APPENDIX A USERS MANUAL A-2 CHAPTER 1 System Description Description, A-2 Major Components, A-2 A-3 CHAPTER 2 Fabrication Introduction, A-3 Crane and Truck, A-3 Instrumentation to Monitor Crane Position, A-4 Scour Measurement Devices, A-8 A-12 CHAPTER 3 Application Guidelines FHWA Scour Monitoring Guidance, A-12 Application of the Articulated Arm Truck, A-12 A-15 CHAPTER 4 Operational Guidelines Data Collection, A-15 Typical Sequence of Events to Collect Data, A-16 A-19 CHAPTER 5 Troubleshooting, Maintenance, and Servicing Troubleshooting, A-19 Maintenance and Servicing, A-19 A-20 CHAPTER 6 Enhancements CONTENTS
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From page 52... ...
Overall, the ability to make portable scour measurements during flood flow conditions has been substantially improved through development of the articulated arm truck. MAJOR COMPONENTS The articulated arm truck consists of four major components: a truck with an articulated arm crane; instrumentation A-2 to monitor the position of the crane in space; instrumentation to measure scour depth; and, computer software to collect, process, and present the results.
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From page 53... ...
The purpose of this chapter is to provide detailed information on the components used and the fabrication required to develop the articulated arm truck that resulted from NCHRP Project 21-07. Adequate information is provided to allow a competent shop to build a similar articulated arm truck.
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From page 54... ...
INSTRUMENTATION TO MONITOR CRANE POSITION Various sensors were installed on the truck and crane to allow geometric calculation of the position of the end of the rotator. An articulated crane provides a very stable platform to deploy scour measurement devices, but it does not provide any positioning information without the addition of other sensors to track the movement of the crane.
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From page 55... ...
polyethylene. The draw wire housing was permanently mounted to a bracket on the truck bed, and a groove on the edge of the plate kept the draw wire in place as the crane rotated.
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From page 56... ...
Given that the truck would always be positioned as close to the curb line or barrier rail as A-6 possible, and given that the bearing of the bridge is a known quantity, the only real location information necessary was the distance the truck had been driven across the bridge and the elevation of the truck. The elevation of the truck could be established from the elevation of the bridge deck, as given on bridge plans, and the height of the truck bed above the bridge deck.
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From page 57... ...
Truck bed and toolbox dimensions. the wireless modem receiving data from the end of the crane, the Campbell data logger for the truck data, the voltage convertor for the acoustic stage sensor, and the DC-AC invertor.
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From page 58... ...
With the truck position defined on the bridge deck, the location of the crane in space could be completely described. SCOUR MEASUREMENT DEVICES As developed, the instrumented, articulated crane could be used to position various scour measurement devices, both directly from the end of the crane and from cable-suspended methods using the winches.
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From page 59... ...
This arrangement facilitated measurements under the bridge deck when direct measurement with the arm or cable-suspended weights was not possible. An accurate location of the sonar measurement could be calculated knowing the position of the end of the rotator, the length of the kneeboard framework, the distance to the water surface, and the angle of the rotator.
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From page 60... ...
The mechanical readouts of the wire rope counters were replaced by pulse counters that allowed electronic readout and input to the data collection software program. The winch and wire rope meter were mounted on a tilting bracket with a collar for a post mounting (Figure A21)
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From page 61... ...
. This eliminated the need to route the sonar cable from the water surface up to the bridge deck and greatly enhanced cable-suspended operations using a sonar device.
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The size of the truck and the automated data collection system facilitate flood measurements by allowing detailed data to be collected in a short time. The articulated arm truck is not a replacement for conventional scour monitoring methods, but is a supplement to those methods, designed specifically for work under adverse flood conditions.
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From page 63... ...
Similar to all scour monitoring methods, the truck has advantages and limitations. Recognizing and remembering what these are will facilitate successful application of the articulated arm truck in a scour monitoring program.
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From page 64... ...
An F-450 truck chassis is not much bigger than a full-sized pickup, and, therefore, the articulated arm truck as developed was easily transportable and maneuverable. Accuracy The desired accuracy of a scour measurement is typically +/−12 in.
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From page 65... ...
Within the software, these coordinates were converted to "bridge" coordinates, as defined by the profile line for the bridge. The profile line is a station-elevation line on the bridge plans, typically along the centerline of the bridge deck.
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From page 66... ...
The middle part of the figure shows the cross section plotted, and at the bottom of the figure are the contour plots developed for each pier. TYPICAL SEQUENCE OF EVENTS TO COLLECT DATA The most common and perhaps the best application of the articulated arm truck is to collect data with the streamlined sonar probe.
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From page 67... ...
Figure A25. Typical results obtained with the articulated arm.
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From page 68... ...
15. If the station-elevation file for the profile line has not been created, do this before pulling onto the bridge deck.
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The calibration position is when the crane is fully retracted and articulated at a right angle over the bridge deck.
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From page 70... ...
The calculation of the location of the end of the crane based on assorted tilt and displacement sensors, along with A-20 a surveyor's wheel to locate the truck on the bridge deck. This system worked well, but created a system of multiple components that required a certain electronic aptitude to operate and maintain.
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