Cryostat Slab and Final design workshop

10 Apr 2018, 08:30 → 11 Apr 2018, 12:00 US/Central

Hornet's Nest WH 8XO (Wilson Hall)

Jack Fowler (Duke University), Joshua Willhite (Fermilab), Mary-Ellyn Mccollum (Fermilab), Tracy Lundin (Fermilab)

Tuesday, 10 April

08:30 → 09:30 Introduction Discussion

The focus of the workshop will focus on structural and electrical isolation issues for the slab on grade at the 4910L. The anticipated construction sequence is: 1. Concrete slab in place 2. Warm structure bottom beams lowered into chamber 3. Before setting beam in place: a. G10 is applied to the bottom flange of each bottom beam. b. beam is set on slab bearing on leveling points. c. all bottom beams are set in place. d. all bottom beams are surveyed and leveled e. the gap under the bottom flange of all beams are filled with grout or grout-like material f. the leveling points are removed Slab flatness requirement: Provide OVERALL FF=25 (approximate +/- ¼ inch) and FL=20 (approximate +/- 5/16-inch) with LOCALIZED FF=17 (approximate +/- 3/8inch) and FL=15 (approximate +/-3/8inch) in compliance with ACI 117, 4.8.5 as determined by the ASTM 1155 test procedure. Electrical isolation requirement: Provide separate grounding systems between the detector/associated DAQ system and the balance of the facility. These systems shall be isolated using inductors. Non-conductive reinforcement shall be provided in the detector cavern side walls and in the detector cavern slabs at the 4910L. Sealing surfaces requirement: Provide all non-floor surface finishes as unpainted shotcrete. Floor of existing south access drifts and all new drifts will be concrete, except mucking ramps. Septum floor concrete is to be sealed.

Speaker: Mr Tracy Lundin (Fermilab)

09:30 → 09:45 Break

09:45 → 11:15 Structural Discussion

1. Review slab loadings under warm structure and anticipated warm structure deflections 2. Leveling screw point loads 3. Grouting under beams 4. Deflections and movements of cryostat on concrete slabs

Speakers: Dimitar MLADENOV (CERN), Mr Tracy Lundin (Fermilab)

Slides Mladenov_18-04-10-LBNF-Cryostat-floor-loading-requirements_(1).pdf Mladenov_18-04-10-LBNF-Cryostat-floor-loading-requirements.pptx

11:15 → 12:15 Structural Discussion A/E

1. deflections of slab system from warm structure loads (slab, gravel under slab, rock mass) 2. point loads on slab, temporary (leveling screws) and permanent (beam flanges)

Speakers: Jack Fowler (Duke University), Mr Joshua Willhite (Fermilab), Mr Tracy Lundin (Fermilab)

Slides Non-Conductive_Slab_and_Point_Loads.pdf

12:15 → 13:15 Lunch

13:15 → 14:45 Electrical Isolation

1. G10 layer and/or elastomeric pads 2. Moisture segregation, gravel drainage layer alternative system, add vapor barrier

Speakers: Jack Fowler (Duke University), Prof. Marzio Nessi (CERN), Theresa Shaw (FNAL), Mr Tracy Lundin (Fermilab)

Slides

• a_DUNE_grounding_concerns_-_impedance_and_capacitance.pdf
• b_DUNE_Infrastructure_Grounding_Plan_-_Changes_due_to_removal_of_rock_septum.pdf
• c_DUNE_Grounding_8APR2018.pdf
• d_Grounding_Concerns_-_impedance_and_capacitance_calculations.pdf
• docdb285_DUNE_Grounding_6JAN2016.pdf

14:45 → 15:00 Break

15:00 → 15:30 Rock Resistivity Testing

The decision was taken to move ahead with the rock resistivity testing in the five rock lithologies along the south access drift at the 4850L consistent with the October 19, 2017 proposal from FMG Engineering to SURF (action FSCF). There is currently no need identified to perform resistivity testing in the detector chambers once they are excavated. Terri will explore the need for testing of concrete slabs either in the south access drift or elsewhere (action Terri).

Speakers: Mr Joshua Willhite (Fermilab), Theresa Shaw (FNAL), Mr Tracy Lundin (Fermilab)

Slides DUNE_grounding_-_small_scale_test_considerations.pdf

15:30 → 16:00 Sealing of Concrete Slabs on Grade

Arup’s EXC scope includes provisions for sealing the concrete slabs on grade on the two rock septums (see requirements). Implementing this requirement will require Arup to identify options and costs if the sealing requirement is expanded to include non-horizontal shotcrete surfaces. If additional floor areas require sealing the cost will be fairly substantial. There are also concerns that if the concrete floor under the cryostats is sealed it will act as a bond breaker preventing a bond between the concrete and the grout that is planned to be installed under the cryostat beams resulting in an ineffective structural solution.

Speaker: Mr Tracy Lundin (Fermilab)

16:00 → 17:00 Summary

Speakers: Jack Fowler (Duke University), Mr Tracy Lundin (Fermilab)

Wednesday, 11 April

08:30 → 10:15 Final Design Changes – Officially in Arup’s Final Design

1. Removal of blast walls on septum and re-alignment of cross drift 2. Use fiber reinforced shotcrete below sill, provide 24-inch gap between bottom of shotcrete and concrete floor, and use nonmetallic rebar in the floor. Provide WWM in drifts between detector caverns and CUC. 3. 3m extension of each end of the detector chamber 4. Mezzanine loads and supports, and lifting eyes 5. Exhaust duct extend down to 4910L

Speakers: Jack Fowler (Duke University), Mr Joshua Willhite (Fermilab), Mr Tracy Lundin (Fermilab)

Slides Arup_Final_Design_Approved_Changes_April_2018.pdf

10:15 → 10:30 Break

10:30 → 12:00 Potential Future Final Design Changes

1. Status of the septum removal discussion a. Excavate to 4910 vs leave 2m tall stub b. Bridge 2. Further extension of the mezzanine 3. Conveyances a. Underslung overhead cranes (2 per cavern) b. Combined use of monorail beams – hoists and crane loads near each other 4. Relocation of overhead utilities to facilitate expanded coverage of crane a. Close current gap in monorail beam with removeable section 5. Temporary utility connections extended to the 4910L and mezzanine area a. Power, water, grounding for welding, compressed air, drainage b. Assumes temporary air supply ducts provided by cryostat drawing from “house air” 6. Adding Alimak and/or permanent stairways

Speakers: Mr Joshua Willhite (Fermilab), Mr Tracy Lundin (Fermilab)

Slides Final_Design_Pending_Changes.pdf