Levelling at TOC can be provide by indirect levelling with precise total station (at least 1 second precision) and prism mounted on a mini-stick. For each GBS, surveyor shall repeat complete set of measurements at least 3 times on the geodetic points. These 3 measures shall be consistent below millimeter accuracy. Check shall be realized on site before leaving GBS. If millimeter accuracy is not achieved, extra measurement shall be carried out till respect this targeted accuracy.
Longitudinal and transverse compensator index errors shall be perform before each GBS measurements and Total station must have a calibration certificate less than one year old.
Topographical Surveyor will access to GBS form EOHF or contractor CTV.
Actual work organization is 12h days working with return to Fecamp (or nearby) harbor by night and onshore accommodation (to be organized by contractor).
Other EHOF or foundation contractor personal (climbing buddy) will access to GBS at same time for safety reason.
Considering number of foundation to be measured (71, i.e.; 30 to 40 days at sea), rotation of personal shall be scheduled.
Surveyor for TOC levelling shall have valid habilitation stated in §4.2 including “boat landing transfer » and « climbing and rescue training » modules .
TOC levelling Reporting :
Result will be plotted on a measurement report with the 3 measurements, the average of these measurement and the deviations from the contractor’s historical data (design data, precast surveys and inclinometry records).
Results shall be transmitted within 2 open day after measurement.
A report shall be done by GBS or by group of GBS (with maximum weekly update).
Report shall include comparison with foundation contractor measurement and investigation of difference.