WP 17.1 Civil Engineering Platform height / vs option Status on M. Manfredi on behalf of WP17.1 team

WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on BASELINE OPTION BASELINE OPTION: Horizontal platform at 442.0m

 Construction of a retaining wall (~45m long) adjacent to the access road, close to SD building;  Power lines and OF buried networks to be diverted (EN-EL). 3 BASELINE OPTION BASELINE OPTION: Horizontal platform at 442.0m Cost: Impact: 1.Retaining wall (45m long): 40 KCHF; 2.Networks deviation: see EN/EL slides on indicoindico Creation of a no-go zone for CE equipment beyond the wall to protect buried lines; Easy access to and from Atlas site (transport); All ‘risks’ linked to the deviation of networks can be anticipated and managed before HiLumi civil works commence. WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on Deviation path TBC by EN/EL

4 ALTERNATIVE OPTION ALTERNATIVE OPTION: Additional platform at 443.5m WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on

5 ALTERNATIVE OPTION ALTERNATIVE OPTION: Additional platform at 443.5m  Raise the surface level of all buildings, but bottom level of foundations is fixed (to stay in good ground conditions); Thus, higher foundations are needed;  Power lines and OF buried networks won’t be touched. Cost: The process to estimate the ‘extra’ costs, w/ respect to the baseline option, is identified below: 0.Baseline lay-out w/ buildings at 442.0m. Platform created w/ excavated ground material WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on Assuming shallow foundations to be executed

6 ALTERNATIVE OPTION ALTERNATIVE OPTION: Additional platform at 443.5m 1.All buildings raised to 443.5m (see example of SHM). 2.Need for 1.5m of fill material to reach higher platform level. Backfilling w/ compacted material under the building footprint Backfilling w/ excavated site material WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on m

7 ALTERNATIVE OPTION ALTERNATIVE OPTION: Additional platform at 443.5m 3.We assume building foundations at the same level as for 442m platform. 4.Excavation w/ support system up to the correct foundation level (Δ=1.5m). WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on m

8 ALTERNATIVE OPTION ALTERNATIVE OPTION: Additional platform at 443.5m 5.Execution of higher concrete foundations (Δ=1.5m). 6.Final backfilling along foundations and technical galleries. WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on m

9 ALTERNATIVE OPTION ALTERNATIVE OPTION: Additional 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 WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on (*) 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.

10 ALTERNATIVE OPTION ALTERNATIVE OPTION: Additional platform at 443.5m Risks: Issues in getting the Building Permit application approved due to the higher platform (pyramid effect, buildings too visible from all perspectives) Shallow HV power lines and OF networks close to SD and SHM footprint. Unsafe and uncontrolled conditions during the 5 year long CE worksite area. Heavy CE machinery will be used by contractor or sub- contractors. Accidental damage to networks cannot be excluded and is likely. Big consequences (time, cost) on the LHC operation in case of fault. WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on m deep 443.5m Sensitive Area !! Strategic Power lines and Optical fibers for CERN-LHC machine below 1.5m of soil, during 5 year long CE worksite area Let’s start to excavate the SD building foundations Deep / piled foundations might be necessary to reach good ground conditions => Higher costs for HiLumi buildings. Transport issue to access the HiLumi site from ATLAS via long and moderately steep ramp. 1.5m soil protection might be not sufficient: earthworks with heavy machine will be carried out nearby (compression and decompression ground effect). Additional costs linked to temporary protection might be necessary. From a construction pov, the necessity to create such a large 2 nd platform and raise all new buildings to avoid a deviation of local networks is difficult to defend.

WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on Risk Comparison Risk 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 permit Base caseAdditional platform may negatively impact application Cost (SMB + EN-EL)≈ 560 KCHFMIN. ≈ 1315 KCHF

Back-up slide WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on

WP17.1 Civil Engineering / Platform height / 442.0m vs m option / Status on