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Browsing by Author "Kawamura, Akira"

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    A Mobile Profilometer For Road Surface Monitoring By Use Of Accelerometers
    Tomiyama, Kazuya; Kawamura, Akira; Nakajima, Shigenori; Ishida, Tateki; Jomoto, Masakazu (2012)
    Surface roughness of a pavement has been recognized to be an important parameter for determining maintenance and rehabilitation needs for road networks. To predict roughness condition reliably, an objective and repeatable profilometer must be used. However, most road agencies, especially for local governments, frequently monitor and determine the pavement condition through visual inspections. This study introduces a new mobile profilometer for more effective data collection and real-time monitoring of the pavement roughness. It consists of two small accelerometers attached to a vehicle suspension system enabling directly measurement of surface profiles using the back calculation of measured acceleration of a vehicle. The measured profile data in the proposed profilometer can be immediately converted to a summary roughness index such as the IRI. The roughness information is simultaneously displayed on an onboard computer in real time. This study also presents profile measurement experiments to verify the accuracy of the new profilometer for roughness data collection and demonstrates its benefits to pavement monitoring of local roads through an application case study.
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    A Routine Monitoring Method Using Weighted Longitudinal Profile
    Kamiya, Keizo; Kawamura, Akira; Glattki, Winfried; Ueckermann, Andreas (2012)
    Weighted Longitudinal Profile (WLP) which is a new index for characterizing longitudinal evenness was introduced in SURF 2008. As a result of sensitivity analysis of the WLP method using longitudinal profile data from the Japanese motorways, each of road surface distress showed its own identical tendency in a relationship between ΔWLP and σWLP. Moreover, since data sites with larger ΔWLP of bridge joint tend to emerge upward in the relation between profile variation Δ and standard deviation of profile σ in octave bands #3 and #4, both octave bands are considered to give critical values to the original surface profile. Because a laser profiler and a mobile profiling system, named STAMPER showed a similar slope of regression between Δ and σ, STAMPER can be used as alternative of laser profiler. By driving a STAMPER-equipped rent-a-car for 5 days on Autobahn, it was observed that IRI is distributed quite similarly between Autobahn and NEXCO motorways. It was also found that octave bands #5 and #6 are prevailing when profile variation Δ is low, or road surface is less deteriorated. Finally if STAMPER can be used routinely and WLP is calculated for surface distress type, this will be an innovative monitoring method.