WP 17.1 Civil Engineering Point 1 - Networks LS2 COMMITTEE – CERN – Pieter Mattelaer (SMB-DI)

HiLumi site at Point 1 - ATLAS LS2 Committee - Point 1 Networks2 Worksite Area (approx. 20% increase in ATLAS surface area )

HiLumi site at Point 1 - ATLAS LS2 Committee - Point 1 Networks3

HiLumi site at Point 1 - ATLAS LS2 Committee - Point 1 Networks4

HiLumi & existing networks at Point 1  Compatibility btwn HiLumi infrastructure & existing networks at Point 1 is problematic;  HiLumi site at Point 1 is small & constrained (CERN land, border, networks, footpaths);  GE authorities require re-use of excavation spoils on site; create platform at level of existing ATLAS site;  Existing networks follow natural terrain slope; expose networks when regrading site;  Difficult to construct buildings close to existing networks; high risk of accidental damage; → proposal to reroute existing networks LS2 Committee - Point 1 Networks5

Base case: Platform at 442.0m LS2 Committee - Point 1 Networks6

Base case: Platform at 442.0m  Existing HV + fiber networks are diverted;  Retaining wall to create physical barrier btwn site and networks;  Platform elevation at ≈ elevation of ATLAS site; ease of access;  Minimal interface btwn networks & HiLumi civil works;  Risk of accidental damage to networks minimized; LS2 Committee - Point 1 Networks7

Alternate: Raised platform at 443.5m LS2 Committee - Point 1 Networks8

Alternate: Raised platform at 443.5m  Existing HV + fiber networks remain in place;  Long 5% ramp btwn HiLumi & ATLAS sites;  Additional costs for deeper foundations;  Building permit issues; spacing btwn buildings;  5 years of civil works adjacent to live lines;  Accidental damage to networks is likely; LS2 Committee - Point 1 Networks9 1.5m deep 443.5m Strategic HV Power lines and Optical fibers for LHC machine Burried 1.5m deep, during 5 year worksite

10 Alternate: Raised platform at 443.5m Cost (*) : Related to raising the level of all HiLumi buildings  Earthworks and filling w/ on-site material up to level:  Cost reduction for reduced soil volume exported from CERN site:  Earthworks and filling w/ compacted material up to level:  Excavation w/ temporary soil support system (Δ=1.5m):  Execution of higher concrete foundations (Δ=1.5m):  Final backfilling along foundations and galleries: TOTAL (*) : 160 KCHF -270 KCHF 235 KCHF 395 KCHF 695 KCHF 100 KCHF ≈ 1’315 KCHF LS2 Committee - Point 1 Networks (*) Lowest possible cost, based on the foundation scheme considered. Costs can easily being much higher if deep foundations need to be executed instead. Consultant will determine whether or not deep foundations are required.

Required distance btwn buildings  Legally required distance between buildings depends on building height calculated relative to original terrain altitude;  Increase in platform elevation = increase in required distance btwn buildings; impacts SR, SF, HSE; LS2 Committee - Point 1 Networks11

Comparison: platform at 442.0m vs m Topic442.0 platform443.5 platform Scope of civil works More limitedMore significant Interface riskDiversion of networks before civil works start, no overlap or interface Complicated interface, e.g. existing networks need to be protected when HiLumi buildings are constructed very nearby (≈2m) Extent of riskLocalized (the places where lines will be cut & jointed) Along entire length of SD17 and partially SHM17 Duration of riskFew days (only during cutting & jointing of networks) Years (during the civil works on HiLumi site ) Risk managementRelatively easy - limited interface between networks and civil works Very difficult - impossible to ensure ‘precision’ with heavy CE equipment Risk levelRelatively controlled risks associated to re-routing of existing networks Uncontrolled risks related to contractor’s care on site ≈ network damage is likely Impact on building permitBase caseAdditional platform may negatively impact application; required space btwn SF and SR will increase, SHE needs to be repositioned Cost (SMB + EN-EL)≈ 585 KCHF (see EN-EL)MIN. ≈ 1315 KCHF LS2 Committee - Point 1 Networks12 → CE recommends 442.0m & rerouting of networks

Time windows to reroute networks  The LS2 PERIOD includes: -Extended Year End Technical Stop (EYETS) (19wks) -Year End Technical Stop (YETS) (13wks) -Long Shutdown 2 (LS2) LS2 Committee - Point 1 Networks13 Source: ‘Framework Schedule from EYETS 2016 to LS2’, Chamonix on Current planning of civil works: Q1 / 2018: site installation; : start of shaft excavation; start of excavation

Planning of HiLumi civil works LS2 Committee - Point 1 Networks14 EYETS (no overlap w/ CE) YETS (no or minimal overlap w/ CE) start LS2 (overlap w/ CE)

Conclusions  Compatibility btwn HiLumi infrastructure & existing networks at Point 1 is problematic;  Main objective is to avoid accidental damage to existing networks during 5 year civil construction site (while LHC is in operation);  WP17.1 recommends HiLumi platform at 442.0m, which requires rerouting of (some) existing networks;  Preferred time window: YETS (or EYETS); to avoid overlap with excavation work during LS2; LS2 Committee - Point 1 Networks15