MMR IAC Hearing Submission on behalf of of RMIT University 12 th September 2016 Tim Marks 1
Airborne Construction Noise Mitigation thresholds should be established particularly for daytime when teaching occurs Guideline noise levels only considers residential scenarios not educational ones CBD North Scenario B, initial shaft construction, is external to Acoustic Shed ( p185,187) See Fig A24 Piling or D-walling? EES not clear which process Piling Lw 111dB - too low (s/b 116dB) D-wall machine Lw 91 dB too low (s/b 105dB) Rock-breakers Lw 114dB too low (s/b 118dB) 2
Construction Noise Targets EPA 1254 only considers residential receivers; and not appropriate for RMIT and projects of this duration, scale or intensity. Preference for NSW ICNG or TfNSW Guideline - proven, comprehensive, robust and effective! Propose typical UK, NSW, USA daytime thresholds for teaching of 35-45dB L Aeq indoors Example: teaching thresholds are 45dB (NSW ) or 35dB (UK BB93) Need to ensure the assessment and mitigation process should be trusted by the community and stakeholders 3
Step 1: Construct guide walls around full perimeter of the excavation Step 2: Excavate panel (day 1) Step 2.1: Final grab pass (day 2) Step 3: Insert rebar (day 2) Step 4: Concrete (day 2) 4
5
Shaft Construction Noise D-walling proposed for CBD North shafts Panel sizes 2.4m wide, 30-35m deep Each shaft perimeter 200m (75m x 25m)~90 panels 2 days per panel, total 180 work days 36 weeks with one Bauer MC-64, 18 weeks with two D walling rigs plus two cranes Crossrail 12-14 hrs per day through London Clay Possibly up to 16hrs per day (0700-2300hrs) through Melbourne Formation Exposure duration –normal working hours 0700- 1800hrs 11hrs/day! 6
Construction vibration Human Comfort – eVDV not appropriate use RMS velocity! (NV 9) No valid basis or precedence for eVDV, very difficult to estimate or predict. Unlike VDV, velocity enables real time validation. TN 032 explains velocity criteria preferred, but stated no applicable standard but ISO 10137 can apply . 7
Vibration predictions (p43) 20 t rock breaker 4.7mm/s Excavator with ripper 1.3mm/s Bored piling 1-3mm/s Sensitive equipment, VC-B (less sensitive, higher vibration), or VC-D(more sensitive, lower vibration) ( Table 3-9 ) Bldg 14, L2 (Radiation Store, Micro CT scanners), L5 (Confocal microscope, VC- B), and L7 Electron Microscopes (0.1 nano-m) do not comply ( Table 11-11 ) 8
Ground propagation (p42) 9
Bored piling (auger) AAS 2011 10
Buffer distances 11
Operational Vibration FTA method commonly used Not used correctly in EES, 3 options: Screening, general and detailed methods a combination (p55) is not appropriate FTA General calculation shows ASHRAE Curve VC-B will be exceeded Detailed studies required Significant long term risks to RMIT 12
Claimed track bed isolation (p57,58) 1 2 Delta 1=10dB Delta 2 = 39dB 13
Floating track slab FST Cost $A2,500 track/m LVT Cost $A800 track/m 14
Ground propagation (p58) 15
Detailed analysis: what Fig 4-7 should show (p56) 16
Operational vibration analysis Vibration mitigation controls are not “standard”, “high” and “very high” Three choices: low medium, high: • LVT (low vibration track) 4-8 dB • IST (isolated slab track) 6-12 dB ( ∆ =2-4dB ) • FST (floating slab track) 15-18 dB ( ∆ =10-11dB) EES Analysis not transparent or convincing with high risks! Force density and transfer mobility measurements required (Fig 4-3) 17
EPR’S As noted, unanimity between all experts in Conclave on most EPR’s Particular concern over NV1 (EPA 1254 should be replaced by ICNG), as no daytime controls Definition of “Unavoidable” works is a smoking gun, undefined and subject to abuse NV 5 to be revised to include teaching and research spaces NVB in its current form is incomplete (CNVMP) Concern over Construction Vibration metrics (NV9) Serious Concerns over achieving Operational Vibration (NV10) thresholds Propagation measurements essential (new 18
Commercial, Medical and Educational Impact Mitigation Mitigation for daytime not required, yet noise at façade >80-90dB (Fig A.24) Building / facade insulation should be required for RMIT when internal thresholds likely to be exceeded. Compares poorly to NSW, UK(Crossrail) and USA (Boston) (35dB - 45dB) Impact and impairment on learning development (Ref AAAC Guidelines, esp for ESL or Overseas students) 19
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