Twelve Quays – Two Levels Project

Presenting PIANC The World Association for Waterborne Transport Infrastructure

Presentation by

James Andrew Smith BSc(Hons) MSc CEng CMarEng MICE MIMarEST Principal Engineer/ Head of Bristol Office Beckett Rankine at the occasion of AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

• Twelve Quays Terminal – Birkenhead

• Western Bank of the River Mersey

• North West England

Owned by:

Credit: Google Earth Operated by:

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

History

• Land part of interconnected docklands • Alfred Basin

• Great Float Rankine

• Designed by Transmarine Beckett :

• Terminal first opened in 2002 Credit

Arrangement

• Pontoon Ro-Ro Berth

• Two berths (North & South)

• Monopile Dolphins

• Fixed Bridge & Bankseat

• 4 Point Torsionally Flexible Linkspan

• Three lane HA/HRo AGA 2021 / 26 & 27 May 2021 Credit: David Byrne Twelve Quays – Two Levels Project

Credit: Stena Line Stena E-Flexer Class

• Longer and heavier than RoPax

• Double Deck: • Faster loading & Greater capacity • Slower sailing = lower emissions • Same Schedule

• Ships design/construction run in Credit: Farrans parallel with berth upgrade

Main Modifications Required

• Upper level loading ramp

• Berth Interface • Stern ramp wider and higher

• Berthing and mooring modifications

• Berth to remain operational!

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Concept & Feasibility Design & Build Contract

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Surveys and Studies

• Topographic & Bathymetric • Utilities & Services • Historical Boreholes • Desktop UXO (Basic and Advanced)

• Laser Scanning • Photographic Surveys • Internal and External UT surveys

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Pontoon Internal Surveys

• Peel Ports commissioned survey in 2016

• All compartments opened but berth remained operational

• Ballast tanks kept full limiting inspection

• Dry tanks fully inspected

• General conclusions:

• Ballasted Tanks: “…good condition and all coatings are showing no signs of significant deterioration.”.

• Dry Tanks: “…suffering from breakdown of coating...”.

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Weld and Joint Inspections

• Visual and MPI inspection of all welded joints on Linkspan

• Torsionally Flexible 4No. Point Support Linkspan

• All welds/joints were free of cracks – remarkable achievement

• Linkspan only required preparation and painting

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Constructability/Installation Assessments

• One berth to remain operational

• Upper Ramp required full possession

• Phase plans developed for each structure

• Lift plans assumed Lara 1 (Mersey Mammoth)

Credit: Jörn Prestien

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Credit: Farrans AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

AGA 2021 / 26 & 27 May 2021 Credit: Farrans Twelve Quays – Two Levels Project

Run-off – Single Level vs Double Level

• Single tier linkspans water runs to Bankseat or drainage points

• Runoff typically collected by interceptor or returns to River or Sea

• Two-tier linkspan water runs to seaward bearings - cascading onto lower deck

• Minor issue to drivers – Big issue to Operators!

• Issue simply resolved with collection trough and down pipe

Credit: Farrans AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Queensway Tunnel Interface

• Ø14m by 3.24km long tunnel – 4No. Lanes

• ~50m from new piles to tunnel

• Existing pile already closer to tunnel

• Plans shared with Mersey Travel (Operator)

• Bored socket piles suit geology and favourable vibration compared to Driving

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Ships Stern Ramp Modifications

• Revised Dwg’s issued during fabrication

• Ships ramp modifications:

• Length – Reduced from 2445mm to 2315mm

• Profile – From flat to new knuckles added

• Hinge – Relocated from top to bottom

• Width – Overall width increased

Implications

• Stop Fender – Already being relocated

• Existing Ramp – No longer compliant BS6349–8

AGA 2021 / 26 & 27 May 2021 Credit: Stena Line Twelve Quays – Two Levels Project

Ships Stern Ramp Modifications

• Options: • New pontoon ramp – High Cost / Delays

• Alter ships ramp – High Cost / Programme Delays

• Bespoke filler piece

• Conforms with BS 6349–8

• Relatively Low Cost

• Retro-fitted

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Upper Linkspan Tolerance and Point Loads

• Large point loads generated by new upper ramp columns

• Internal Stiffeners sufficient but tolerances required

• Ravestein opt for new over-sized 50mm landing plates

• Greater Tolerance

• Reduced confined space works

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

AGA 2021 / 26 & 27 May 2021 Credit: Farrans Twelve Quays – Two Levels Project

Pontoon Internal Painting and Fatigue Cracking

• Ballast Tanks drained to enable blasting and painting

• Discovery of large fatigue cracks – Flange and Webs

• Repairs carried out previously but unrecorded history

• Ongoing study to assess the root cause – Fatigue Modelling

• Temp repair using ‘Vee-and-Weld’ method.

Credit: Farrans AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Ramp Modification and Cracking

• Ramp removed for painting and modification

• Cracks to 4No. ‘Sniped’ stiffeners

• Ongoing study to assess the root cause

• Temp repair using ‘Vee-and-Weld’ method

Credit: Farrans

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

Credit: Farrans

AGA 2021 / 26 & 27 May 2021 Twelve Quays – Two Levels Project

AGA 2021 / 26 & 27 May 2021 Credit: Farrans THANK YOU

AGA 2021 / 26 & 27 May 2021 Q&A

AGA 2021 / 26 & 27 May 2021