Walk-Behind Surface Profiler
Walk-Behind Surface Profiler Testing (Click to Zoom)
The walk-behind surface profiler is a device used on pavements to record surface elevation profiles and determine roughness indexes. In civil engineering applications it is used on all pavement types, and can also be utilized on indoor flooring. The data it collects can be used in evaluating construction, maintenance, and for testing purposes. Similar to the inertial profiler, the walk-behind surface profiler generates surface profiles that can be used in software to simulate other roughness devices and aircraft acceleration responses.
The device consists of a wheeled cart that contains the instruments, and a push handle. The sensor cart includes two inclinometers, one mounted on the front and one on the rear, a temperature sensor, and an optical encoder computer system. An inclinometer measures angular slope based on voltage input, and converts to elevation using trigonometric functions. The device’s suspension provides stability and improves accuracy over rough pavement. The wheel configuration is adjustable, just like the walking road profiler's supports.
To record a profile, an operator pushes the device down the path at a slow speed, approximately 2.5 miles per hour to ensure accuracy. The device displays the current speed, distance traveled, and elevation change from the start to assist operation. By default, the data is unfiltered. Roughness values can be obtained from a one-way survey of the path after applying the appropriate filtering. Obtaining an elevation profile requires a two-way survey, where the path is recorded forward and back again. Starting and ending at the same point allows for correction of any compounding error.
The walk-behind surface profiler is quite versatile overall in that it does not have any major drawbacks. It can be operated at a reasonable speed, is reasonably portable, and has good accuracy. It can be used for longitudinal and transverse field testing, unlike larger or more unwieldy devices. Its main feature is the ability to record full pavement profiles for simulation purposes, allowing the approximation of many other devices with one test.
Walk-Behind Surface Profiler Wheels and Suspension System (Click to Zoom)
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