Tarmac 3D modeling and deformation analysis of airplane roundabout loops / Athens International Airport “El. Venizelos” – Greece
The airplane traffic at the Athens International Airport towards its 2 air-corridors (eastern and western) is regulated through 4 roundabout loops, 2 for each corridor. Due to the traffic load, the fact that the heavy aircrafts often have to stop at the loops and the type of the pavement, the tarmac at those 4 areas has developed noticeable deformations. So, the technical department of the A.I.A., in order to define the extent of the damage and decide what kind of corrective actions should be taken (from simple tarmac repairs to full pavement reconstruction), requested a detailed 3D modeling of the tarmac surface, followed by a complete deformation analysis. The methodology should combine a high level of detail (measurement every 2-3 cm), speed (each loop could remain closed only for a few hours) and accuracy (<1cm for elevations).
A 3D laser scanning survey, using the Optech ILRIS 36D Laser Scanner, was performed (6 to 9 scan positions per area, scanner on top of a car, tripod mounted, 20% pan-tilt base overlap, distance between scans <50m).
Georeference was obtained using conic and circular targets, measured from the airport’s geodetic control points.
An aligned and georeferenced pointcloud for each area was created.
Sub-sampling (3cm) and triangulation of data points was performed, followed by an optimization and decimation of the model from 3 million triangles to less than 5000 triangles, with insignificant elevation information loss.
An elevation map (contour spacing 2cm) was generated for each area.
Cross sections were extracted based on the above models and deformations were properly detected, measured, demonstrated and presented in table reports.
Results have been evaluated by the A.I.A. technical department and different corrective actions have been decided for each loop area.
Results – Conclusions
Laser scanning has proven to be not only the most effective method for the project’s purposes, but in fact the only one applicable, offering the required resolution / level of detail and accuracy at a speed that was acceptable for the airports restrictions.