2018 Fiscal Year Research-status Report
Practicability study on drive-by methods for vibration-based bridge damage detection and modal identification
| Project/Area Number |
17K14716
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| Research Institution | Kyoto University |
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Principal Investigator |
張 凱淳 京都大学, 工学研究科, 講師 (50751723)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | bridge inspection / damage detection / drive-by inspection / moving vehicle / VBI |
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| Outline of Annual Research Achievements |
This study aims to present the practicability of drive-by methods for vibration-based bridge damage detection and modal identification by developing a practical drive-by vibration sensing system. The research achievements in the second year can be summarized as follows.
1. A real-life drive-by measurement system was proposed and assembled
Based on the findings from the laboratory experiment conducted last year, a real-life drive-by measurement system was proposed. It was a tractor-trailer system. The focus herein is that the trailer was homemade, whose frequencies can be tuned to a higher range for avoiding close resonance with bridge vibrations by changing the body mass and the suspension stiffness, while the tractor was a commercial car. In addition, the trailer was not affected too much by the vibration caused by the tractor’s engine.
2. The drive-by measurement system was tested in field
After being designed and assembled, the trailer was firstly tested in laboratory by means of free vibration tests to identify its dynamic characteristics in stationary state, then tested on a flat road by moving vehicle tests to identify its dynamic characteristics in moving states, and finally tested on a 40-m long bridge by means of moving vehicle tests to investigate its feasibility.
The above achievements were presented in several national and international conferences.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In my proposal, I planned to conduct the following studies in the second and third years.
1. developing and validating incorporated analysis method
2. proposing a full-scale sensing system and testing it in field
While Item 1 will be addressed in the coming year, Item 2 was conducted in this year: a full-scale real-life drive-by measurement system was proposed, assembled, and then tested on a simply-supported box-girder bridge in field. The design and assembly of the system progressed smoothly. However, it was our first trial in field and some difficulties and limitations were identified. Firstly, the trailer’s yawing mode was constrained by the joint, and therefore the trailer was unable to turn left or right, introducing some inconvenience. Secondly, the trailer was too light so sometimes it jumped away from the pavement. Thirdly, the road surface roughness still greatly and adversely affected the vehicle vibrations. We believe it was a good start and those difficulties and limitations are to be address in the future.
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| Strategy for Future Research Activity |
From the third year, we plan to develop and validate incorporated analysis methods as per scheduled. We have developed several analysis methods for identifying bridge modal properties and detecting potential damage from the moving vehicles’ vibrations. Also we plan to develop a finite element model updating framework to identify a bridge’s mechanical properties by the drive-by method. Those analysis methods will be incorporated into the laboratory-scale sensing system and validated with our scaled bridge. Foreseeable challenges are the too large roadway roughness-induced vibrations and the too small bridge-induced vibrations. Its solutions or improvements will be proposed in both hardware and software ways and tested repeatedly in laboratory. Moreover, those repeating laboratory tests would help us discover other problems and challenges that hardly stand out in numerical simulations.
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| Causes of Carryover |
Reasons for incurring amount: Because this is our first trial to design and assemble a real-life trailer as a measurement platform, we spent our budget carefully in a very economical way. The price of the materials and components of the homemade trailer were surveyed carefully and bargained strongly. The sensors were borrowed from other labs so that so far no budget was spent on sensors.
Usage plan: A great portion of the article costs was devoted to the materials and components of the trailer but not yet to new sensors. The budget will be spent as scheduled: to buy new sensors, to pay the travelling expenses and publication costs, etc.
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Research Products
(3 results)
