Planograph
A planograph (also planograph ) is an internationally used measuring device for determining the longitudinal evenness of roads and thus an important instrument for quality assurance in road construction. Roads with inadequate longitudinal evenness have a significant negative impact on driving comfort and safety. The use of the planograph reliably replaces the complex staff measurement and the results are recorded and evaluated electronically or on wax paper.
principle
The planograph consists of a framework made of metal, on which 10 fixedly mounted wheels and in the middle one vertically movable wheel are attached one behind the other in a line. The outermost wheels are four meters apart. The planograph is drawn across the traffic area in the direction of measurement (forward and backward measurement possible). The measuring wheel in the middle detects depressions or elevations in the longitudinal direction of the roadway by recording its movements electronically or by a measuring recorder on continuous paper.
The data obtained in this way are used to assess or approve a traffic area. Different limit values apply depending on the road surface. For asphalt surface courses, for example, the tolerance for unevenness is 4 mm per 4 m.
A disadvantage of measuring with the help of a planograph is that only short waves or bumps on the road can be recorded compared to the support length of 4 m. This disadvantage also applies to measurements with the 4-meter staff.
literature
- ↑ TP Eben - Contact measurements , technical test specifications for evenness measurements on road surfaces in longitudinal and transverse directions, FGSV Cologne, 2017, ISBN 978-3-86446-232-0 .
- ↑ Manual of contract documents for highway works; Volume 1: Specification for highway works, Series 700 - Road pavements - General, # 702-7, PDF
- S. Velske, H. Mentlein: Road construction technology . Werner Verlag, Düsseldorf 2002, ISBN 3-8041-3875-6 , p. 256 ff .