Installation of Primary Permanent Ground Markers

Tender description

It is intended that HS2 Ltd procures the services of a supplier who shall: • Install the Primary Permanent Ground Markers (PGM) along the line of the route (London to Crewe). This will enable a survey grid to be defined on the ground by the network of installed PGMs. • Observe and compute all PGMs using GNSS ETRS89 co-ordinates in latitude, longitude, ellipsoidal heights and OSGB36 for plan and OS Newlyn datum for heights • Produce a detailed survey report incorporating witness diagrams of all PGM locations and schedule of co-ordinates of all survey control points Scope As part of requirements for the Enabling Works Contract for the HS2 route, it is the intention for the services of a supplier to be procured who shall be responsible for: • Installation of the Primary permanent ground markers which are the first-order survey control points • Observation of the PGMs and production of a summary of computation results, including standard errors achieved and error ellipse sizes • Production of a Survey Report upon completion of the works • Production of a layout of survey PGMs with lines showing those operating simultaneously with a map background. • Production of schedule of coordinates of all survey control points established in .xls format. • Supporting information shall be in the form of Station descriptions (witness diagrams) for all PGMs. The Witness diagrams shall record the following information in relation to the PGMs (but not limited to): • PGM hierarchy (e.g. Primary), accuracy and name • plan co-ordinates and grid • height value • type of marker • photograph of marker and its location • sketch or plan with dimensions to adjacent visible features, scalable/shown to 1cm. Please note that all contact MUST be made through the HS2 Bravo eSourcing portal. No other communication is permitted or will be acknowledged.