Browsing by Author "Hattingh, Werner Visser"
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- ItemEvaluating the use of low-cost technologies for pavement surface evaluations(Stellenbosch : Stellenbosch University, 2020-12) Hattingh, Werner Visser; Jurgens, Chris; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.ENGLISH ABSTRACT: iAbstractSouth Africa has the tenth largest road network in the world,with a total road network of 750 000 kilometres. The Provincial governmentsareresponsible for the regional roads, while local municipalities are responsible for localroadsand city streets. Both these management authorities monitor road conditions through a time-consuming visual inspection and reporting process as perthe TMH 9 manual.Current road surface inspection methods used by the South African provincial governments include a two-phase visual inspection. This method can be time-consuming,resulting in increased inspection and maintenance costs. Visual inspections rely on the trained perspective of the assessor. This may lead to inconsistencies between assessors or inspections.Provincial governments in South Africa perform the routine surface inspections on an annual basis which result in high ongoing costs of pavement surface inspections. Alternative pavement inspection methods with low-cost hardware could, therefore, reduce the cost of pavement surface inspections and improve data accuracyand safety. This thesis evaluatesdifferent inspection platforms based on theirtime,cost and qualityperformance. The three platforms evaluated include traditional inspection methods (TMH 9), as well as UAV platforms and ground-basedvehicle platforms fitted with different low-cost technologytypes. The investigated technology types includea digital camera, thermal device and LIDARdevice.The evaluation includesthe testing of technology types and vehicle platforms to determine thedata collection speed limit, the ability of the technology to capture different crackwidths andthe sensitivity to changing light conditions.The testing highlighted that the digital camera required additional lighting to reduce the sensitivity to changing light conditions. The required inspection time dependsonthe maximum platform travel speed untilone image pixel becomes blurry.The image blurdepends on the shutter speed, field of view, height above the pavement surface and the time-lapse speed of the device. It was determined at two meters above the pavement surface,that thethermal SeekShotPro (9Hz) can collect data at 68km/h compared to 19.5km/h forthe GoPro Hero 8 digital camera. The total cost includesvariable costssuch as the operator cost, vehicle running cost and exchange rate.AMonte Carlo analysis wasfollowed to determine the most probable cost for each platformand technology typebased on different distribution models developed for the cost evaluation. Thermal devices fitted to the different platforms resulted in a lower operating cost for each platform. It was found that theUAV platform hasthe lowest operating cost,followed by a ground-based vehicle platform and the traditional inspection method.The quality of each platform ismeasured via a comparison ofthe pavement assessment list provided in the TRH 22 manual.The ability of each technology type to identify different distress mechanisms depended on the ability to measure distance and identify different crack widths accurately. It was determined that the thermal devicecould identify 73.03% of the different distress mechanisms, while the digital camera and LIDARdevice could identify 68.54% and 38.58% respectively. Ultimately the ground-based vehicle platform fitted with a combination of a thermal and LIDARdevice proved to be the most suitable for pavement surface evaluations. Using a combination of deviceswill increase the numberofdifferentdistress mechanisms identified to 86.14%.