Works for complete or part construction and civil engineering work

Tender description

This contract is divided into 2 lots. Lot 1 — Coolkeeragh to Magherafelt Transmission Tower Foundation Assessments and Lot 2 — Transmission Tower Foundation Assessments and Site Investigations. There are various work elements required to complete the intrusive tower inspections: 1) Walkthrough and Survey; 2) Muff Survey; 3) Intrusive Investigation; 4) Site Investigation. The objective of the intrusive investigation is to obtain information in order to help determine the capacity of each tower foundation. Information such as foundation type, size and condition will be obtained. Further information such as ground descriptions and water table measurements will also be taken during the excavation works required to complete the intrusive investigations. The transmission overhead line between Coolkeeragh (Londonderry) and Magherafelt is a double circuit, lattice tower line operating at 275 000 Volts. It was constructed in 1963 and is one of the oldest on the NIE Networks system. NIE Networks aim to refurbish the line as a whole, as well as upgrading the existing conductor to carry more current. In order for this to be completed the current loading capacity of the tower foundations must be determined. As part of the process to determine the current capacity an intrusive investigation must be carried out on each tower foundation on the line. There are a number of work elements required to complete the intrusive tower inspections, which are as follows: 1) Walkthrough and Survey; 2) Muff Survey; 3) Intrusive Investigation; 4) Site Investigation. The objective of the intrusive investigation is to obtain information in order to help determine the capacity of each tower foundation. Information such as foundation type, size and condition will be obtained. Further information such as ground descriptions and water table measurements will also be taken during the excavation works required to complete the intrusive investigations. The activities described above shall be carried out in accordance with the guidelines set out within this specification and all relevant health and safety standards. It should be noted that all work will be carried out under live 275 kV live overhead lines and accordingly works shall to be carried out as per NIE Networks safety rules. The NIE Networks’ transmission system has a route length of 1 324 km and operates at 2 voltage levels. The higher voltage 275 kV network comprises 400 km of double circuit tower lines in 11 Sections. The majority of the 275 kV network was constructed in 1966-70, with final circuits completed in 1978. The 110 kV network comprises 924 km of overhead line. This is made up of 348 km of tower lines (mostly double circuit) and 576 km of single circuit portal lines, with tower structures at angle positions and intermediate pole structures. The majority of towers were constructed from the 1940s up to the late 1970s, with the majority of portal lines erected in the 1950s up to the late 1970s. To complete tower foundation assessments there are a number of work elements to be completed: 1) Walkthrough and Survey; 2) Muff Survey; 3) Intrusive Investigation; 4) Site Investigation. The objective of the intrusive investigation is to obtain information in order to help determine the capacity of each tower foundation. Information such as foundation type, size and condition will be obtained. Further information such as ground descriptions and water table measurements will also be taken during the excavation works required to complete the intrusive investigations. The activities described above shall be carried out in accordance with the guidelines set out within this specification and all relevant health and safety standards. It should be noted that all work will be carried out under live overhead lines operating at or above 110 kV and accordingly works shall to be carried out as per NIE Networks safety rules.