ICE Coasts,Marine Structures & Breakwaters 2023

Welcome

Portsmouth’s Natural Harbour has led it to be a maritime base for centuries, starting with the Romans in Portchester at the top of the harbour. King Richard I gave the city a Royal Charter so he had a safe port to return from the Crusades (and where the star and crescent on the city’s coat of arms comes from).

Significant developments were made to the Naval Dockyard and city’s defences in the Napoleonic era around the turn of the 19th Century, some of which have been rediscovered as part of the Southsea Coastal Scheme, which you will see as part of the Technical Visit. One of the areas visited on the scheme will be Southsea Castle, from where Henry VIII saw his ship Mary Rose capsize and sink near the entrance to Portsmouth Harbour.

The Victorian era brought HMS Warrior (1860) into the fleet as the first iron clad warship, along with Brunel’s father Marc, working on dockyard buildings and son Isambard Kingdom Brunel, born near the naval dockyard.

As works are undertaken to service the current Royal Navy, so the Harbour changes for the future. As part of the Queen Elizabeth class aircraft carrier works new navigation markers were built guiding vessels into the harbour, which was deepened to accommodate the new ships. New jetties were also constructed which included shore to ship power, providing more sustainable options for the future.

We hope this technical visit gives you a flavour of Portsmouth as a waterfront city and home of the Royal Navy.

Visit Areas

The Technical Visit will start from the Conference venue, the Marriott Hotel, in the mainland part of the City of Portsmouth. Travelling south on the Motorway you will you will travel alongside Tipner Lake, which forms the western end of Portcreek and links it with Portsmouth Harbour, and enter Portsea Island which forms the majority of the City. The M275 forms one of 3 road links on and off Portsea Island to join the rail link.

As we head towards the city centre, from the motorway you will see the Whale Island, Home of the Navy Command Headquarters and Commercial Ferry Port on the western edge of Portsmouth Harbour.

Your morning will be spent on the Southsea Coastal Scheme. Southsea is the seafront area of the city which forms a large part of the public open space for the city through the seafront and Southsea Common. Dominating the seafront is the Portsmouth Naval Memorial, which was erected in 1924 and is a navigation aid as well as a memorial (there are identical memorials in Plymouth & Chatham).

Following lunch we will transfer to the Historic Dockyard to board a boat for a tour of the harbour picking up recent naval infrastructure works which are outlined in this booklet. Portsmouth Harbour has the largest number of shipping movements in the UK, with a variety of naval, commercial and leisure craft. Movement in the harbour is overseen by the King’s Harbour Master with systems similar to air traffic control due to the volume of traffic.

Timetable

Time Location

10:30 10:40

10:40 11:15

11:15 12:15

12:15 12:55

12:55 13:15

13:15 14:15

14:15

Introduction to Southsea Coastal Scheme (Pier Rd Offices)

Guided Tour of Long Curtain Moat completed frontage

Walk to and site visit of Southsea Castle frontage

Lunch & intro to Dockyard works (Pier Rd)

Transfer and walk to Historic Dockyard pontoon for Harbour Tour

Harbour Tour (Solent Cruises).

Coach pick up from Historic Dockyard to return to Marriott

Travel from Marriott to Southsea

SOUTHSEA COASTAL SCHEME

SOUTHSEA

Plans and Stages

It should be noted that while the dates and the phasing of the Southsea Coastal Scheme are correct at the time of printing, these may be subject to change.

Frontage 1

Long Curtain Moat

Primary defence: Vertical wall

Secondary defence: Existing high ground and bund

Beach management: Natural processes

Frontage 4

Southsea Castle

Primary defence: Rock armour revetment and low vertical wall

Secondary defence: Existing high ground and vertical wall

Beach management: Natural processes

Frontage 5

Pier

Primary defence: Stepped revetment (Pyramids)

Secondary defence: Vertical wall with landscaping

Beach management: Beach nourishment

Frontage 3

Southsea Common

Primary defence: Rock revetment

Secondary defence: Set back earth bund

Beach management: Natural processes

Long Curtain Moat

Clarence Pier

Southsea Common Southsea Castle

The Pyramids

Pyramids to the

Plans and Stages

No major work will be carried out in this area for approximately the next 50 years.

Long-term beach management and monitoring plan put in place to ensure adequate flood protection remains in place.

Frontage 3

Southsea Common

Primary defence: Rock revetment

Secondary defence: Set back earth bund

Beach management: Natural processes

Frontage 5

Pyramids to the Pier

Primary defence: Rock groyne (Pier)

Secondary defence: Vertical wall with landscaping

Beach management: Beach nourishment

Frontage 6

Canoe Lake

Primary defence:

Stepped revetment

Secondary defence: Mix of high ground bund and vertical wall

Beach management: Beach nourishment

Frontage 2

Clarence Pier

Primary defence: Existing sea wall

Secondary defence: Set back bund

South Parade Pier

Eastney Esplanade

Canoe Lake and Rose Gardens

CANOE LAKE

FRONTAGE 6

CLARENCE PIER

FRONTAGE 2

Eastney Esplanade

Frontage 1 Construction

Long Curtain Moat

Activity in this section has included:

• Demolition of the old seawall and a new seawall built

• Height and width of promenade increased

• 525 linear metres of sheet piles installed, totalling 6,300m2 (if the piles were laid end to end, this would make a total of 12km of sheet piles driven into the ground)

• 11,474 tonnes of rock imported from Norway

• 118 parapet units and 18 special parapet units, totalling 136 units

• 5,700 tonnes of in situ concrete

• 18 rock pools

• Two new bridges, lighting, plants and seating installed

• Renewal of the Clarence Pier carpark

Frontage 4 Construction

Southsea Castle

Activity in this section has included:

• 145,000 tonnes of rock imported to make up the new sea defences

• Phase 1 of rock work completed and phase 2 commenced November 2022

• 40 tide pools installed

• Installation of parapets delineating the new split level promenade

Happening now at Southsea Castle is phase two of the rock work, involving placing the rock up against a 0.6m upstand wall to provide the primary flood defence. Around the castle the promenade will split to form a two-tier public area with seating incorporated between the two paths, providing a ‘theatre of the sea’ social space.

Heritage

Throughout Frontage 1 (Long Curtain Moat), materials have been meticulously sourced to ensure they closely replicated the original sea defences, with Purbeck limestone (taken from the same original limestone seam of material as the original Long Curtain Moat) and granite units making up the new defences. Approval from Historic England for the materials to be used came after more than a year of consultation and testing to ensure the new design was sympathetic to the historic area. This is a great example of pioneering engineering work undertaken by the team and has been extremely well received by the community.

There have been several unexpected discoveries made during the works at historic Frontage 1, and the Scheme worked

closely with Historic England and Wessex Archaeology as finds were unearthed. The team uncovered the remains of the 17th century city walls and defences, as well as original masons’ marks inscribed on the stones.

The first historic find came back in late 2020 when sections of the historic defences of Old Portsmouth, possibly dating back to the 17th century, were unearthed on Southsea’s MoD field as it was being set up as a materials processing compound.

This was followed by a section of the original wall being uncovered by Long Curtain Moat which has been conserved and remains exposed in the finished works. The finds in this area have been recorded for posterity and will be included on information boards for the public along the new promenade.

Near Southsea Castle, a swivel mount gun emplacement was exposed beneath the existing promenade in front of the castle, which has been dated to the early 19th century. In addition, a large triangular defence structure was found to the south of the gun emplacement.

This is likely to be part of the redesign of the castle by the Dutch engineer Bernard De and is physical evidence of the large scale upgrading of the historic defences of Portsmouth that took place in the late 17th century. This significant find will be incorporated into the esplanade with appropriate interpretation.

Heritage

Other finds in this area include:

• The bowl of a smoker’s pipe that looks likely to originate from Fareham Pipe Makers in the 1800s

• A copper bell likely dating back to Victorian times found while digging a trench to connect electricity on Castle Field

• A piece of stamped pottery from the Southsea Baths & Assembly Rooms, dating back to 1871!

• Sections of Edwardian promenade.

Environmental Environment & Wildlife Protection

The Scheme aims to be a zero waste project and a materials processing site has been set up on the Ministry of Defence Field on Pier Road to achieve this goal. The Scheme plans to reuse site won material as fill for the new sea defences and road raising, to provide fill material for the new sea defences and road raising.

Here are some impressive statistics on savings to be gained from the materials processing site:

3,950t THIS WILL SAVE... 87,000m3

24,600

Across two frontages, the Scheme has installed 58 tide pools to enhance marine life. These concrete pools are designed to create ecosystems that mimic natural rock pools found on rocky coastlines.

Respecting the habitats of wildlife is a priority of the Scheme, and the team worked closely with Natural England on mitigation strategies for the Brent Geese that inhabited an area used by the (now) project office on a section of Southsea Common. An area of the Ministry of Defence field on Pier Road is fenced off for the geese during winter, with decoys and audio devices installed to attract the birds to the field.

We are scheduling work around the purple sandpiper birds that overwinter in the area around Southsea Castle, restricting noisier work to months outside the time the birds feed in the area. Seed rocks have been planted to speed up the colonisation of the new rock structure by the castle, providing feeding matter for the birds.

LORRY MOVEMENTS

Environmental

Coming Next

FRONTAGE 5 - WEST

Work to the seafront area between the Pyramids and Speakers Corner will commence in Summer 2023. The Defences here will comprise of a stepped revetment for the majority of the

frontage transitioning from a vertical wall at the western end. There will be terrace planting leaving from the promenade to public open space at road level.

FRONTAGE 3 - SOUTHSEA COMMON

Work will get underway in winter 2024. The primary sea defences here will comprise stepped areas of promenade and rock. For time and efficiency reasons, the rock for the work has already been imported from Norway and is being stored on

the seafront near Blue Reef Aquarium. The promenade and road will be raised; a two-way cycle lane will be incorporated; and the promenade will be a constant 8m wide along the length of the frontage.

HMNB PORTSMOUTH CHANNEL

PORTSMOUTH

DREDGING

Project Sheet

Project Description

This high profile, nationally significant capital dredging project was undertaken utilising several divisions of the Boskalis group and deploying numerous specialist dredgers and other vessels from the extensive Boskalis fleet. The original major scope of the work was the deepening and widening of the approach channel, berths and turning circle requiring the dredging of approximately 3 million m³ of material. This comprised mainly of silt, sands and gravels with smaller quantities of clay and peat. The design of the dredged side slopes was carried out by Hydronamic, the Boskalis in-house engineering consultancy.

Approximately 750,000 m³ of dredged material was deemed suitable for possible beneficial use in the future. Boskalis Westminster have therefore placed it in our underwater stockpile, at the site of an existing Crown Estate winning area, for recovery and re-use when a suitable project requiring coarse sand and gravel arises. Several loads were also sold directly into the local aggregate market for use in the construction industry. Unsuitable material was transported to the designated licensed disposal area close to the Nab Tower.

In addition to the dredging, a debris removal operation was required. During the project, the number of obstructions with the potential to both delay the dredging and possibly cause significant health and safety risk was found to be much greater than originally envisaged. A team of UXO (unexploded ordnance) detection and removal specialists from Boskalis Hirdes deployed to site using bespoke equipment fitted to a long reach excavator on our Stemat 87 barge. The multitool head on the excavator comprised an underwater camera, pump/jet and a grab. Objects detected from the Sub-Tem magnetometer survey were investigated and, once deemed safe, removed from the seabed. In the event UXOs were detected, operations were handed over to the Royal Navy bomb disposal teams who relocated them into safe water for detonation.

The discovery of a 2000lb aluminium ground mine resulted in the Boskalis Hirdes team investing in state of the art technology and developing their own ‘Sub-Tem’ underwater sledge which is not only capable of detecting ferrous objects, but also all other metallic targets including aluminium, copper and bronze.

PORTSMOUTH APPROACH CHANNEL FOR QUEEN ELIZABETH CLASS AIRCRAFT CARRIERS 2015 - 2017 PORTSMOUTH, HAMPSHIRE, UK

Causeway - Terramare - Terraferre - Manu Pekka

Terramare

Causeway

Project Sheet

PORTSMOUTH APPROACH CHANNEL FOR QUEEN ELIZABETH CLASS AIRCRAFT CARRIERS 2015 - 2017

PORTSMOUTH, HAMPSHIRE, UK

This resulted in the safe detection and removal of numerous items of UXO plus almost 1,500t of other debris including cables, wires, anchors, chains as well as archaeological artefacts such as cannons and cannon balls.

The utilisation of numerous Boskalis vessels has ensured that the correct equipment for efficient execution of each task and section has been achieved. We have employed trailing suction hopper dredgers; Freeway, Shoalway, Causeway, Sospan Dau and Deo Gloria plus the backhoe Manu Pekka in conjunction with our Terraferre tug and barges. The UXO and debris clearance was undertaken from the crane barges Stemat 87 and Strekker. We used the newly built multi-purpose vessel Terra Plana for ploughing and bed levelling, in conjunction with purpose built large plough Norma.

The sensitive location of Portsmouth Harbour also required extensive environmental monitoring of turbidity and water temperature using a‘smart’buoy in the approaches, calling on valuable experience gained on the similar Southampton Approach Channel Dredge project a few years earlier.

Another key aspect of the project, in addition to the engineering and technical challenges, was the liaison with the local stakeholders. For every operation, stakeholder risks had to be assessed involving extensive communication. In addition to the marine traffic of military, commercial, ferries and leisure craft, the harbour entrance is adjacent to a busy shopping centre, bars, restaurants and residences. All buildings which could potentially be affected by the works were surveyed prior to commencement and surveyed again on completion to ensure that there had been no detrimental effect.

Stemat - Crane barge

Stemat - Crane barge

Terra Plana

Manu Pekka Terramare - Terraferre

HMNB PORTSMOUTH BASE PORTING INFRASTRUCTURE

PORTSMOUTH PORTING INFRASTRUCTURE

HMNB Portsmouth QEC Base Porting Infrastructure

Purpose

The Queen Elizabeth class is a class of two aircraft carriers which are the central components of the UK Carrier Strike Group. Each with a displacement of 65,000t, the two vessels - named the HMS Queen Elizabeth and HMS Prince of Wales - are the largest warships ever constructed by the Royal Navy.

With HMNB Portsmouth selected as the home base, the Defence Infrastructure Organisation needed 21st-century moorings to accommodate the two carriers. We were contracted to design and construct upgrades to the existing jetties that were up to 90 years old and install other new infrastructure to support the vessels.

What we did

We demolished and replaced the defective sections of the existing jetties and replaced these sections with tubular piled and concrete deck structures, including strong points to support the 80t fender spacer units. We also installed new infrastructure such as navigation aids, substations, and a dedicated high voltage electricity supply to power the carriers when they are in berth.We identified weak points so we could retain the structurally sound parts of the existing decks. Detailed laser scanning and site/ground investigations helped us to identify weak areas and design structures to take the fender support unit loadings.

After breaking out the deck sections being replaced, we installed pile sleeves over the existing piles. We then

placed precast pile caps and spanning panels, stitched together with concrete pours.

We preserved a historic dock wall that the Princess Royal Jetty was propping. A static load test, informed the need to strengthen the existing deck edge, reducing the risk of damage through overloading.

The fender spacer units are needed to allow the carriers to berth safely, spanning the 20m of hull flare. We designed, fabricated, and installed the 80t structures, which can be removed and safely stored when the carriers are not berthed. At each fender support unit location, we used a 350t crane barge to install fender piles, precast pile caps and fender panels.

We used a crane barge to install 14 navigation aids to guide the carriers through Portsmouth Harbour, mooring

HMNB Portsmouth QEC Base Porting Infrastructure

dolphins, and a pre-fabricated access walkway at Victory Jetty’s southern end.

Our shore-power supply reduced energy consumption caused by ships burning generator fuel when berthed. We built a substation and installed 2.6 miles of cable to connect to the national grid. We also developed bespoke

Project successes

We brought the Princess Royal Jetty into service three months earlier than the client’s original programme. In August 2017, huge crowds lined Portsmouth Harbour to welcome HMS Queen Elizabeth for the first time, gaining nationwide media coverage. We went on to complete Victory Jetty two months early, and the two carriers were able to berth next to each for the first time in November 2019.

rotary frequency converters, to transform the typical 50Hz frequency to the 60Hz that ships operate on.

We designed and installed a bespoke telescopic cable boom to bridge the gap from the jetty to the vessel. This sends the 11,000-volt shore-power supply to the berthed carriers and tracks the ship to maintain connection during tidal movements.

Our sustainable construction efforts were recognised through the winning of the CEEQUAL ‘Very Good’ Whole Team Award. CEEQUAL is the world’s leading sustainability rating scheme for infrastructure, engineering and public realm projects. The Defence Infrastructure Organisation also presented us with a Sanctuary Award, which recognises outstanding sustainability across the defence estates.

HMNB Portsmouth Upper Harbour Ammunition Facility

Purpose

As well as being the home of the Royal Navy, Portsmouth Harbour also houses an offshore ammunition facility. The critically-important jetty, located in the middle of the harbour, fits vessels with everything they need for battle – from missiles to bullets. The original facility, built in 1923, needed to be replaced as it was unable to support modern warships.

A government’s defence review identified Type 45 frigates as a key component in the future defence strategy, so the Defence Infrastructure Organisation (DIO) contracted VolkerStevin to design and build suitable offshore docking and loading facilities.

What we did

Located 800m offshore in Portsmouth Harbour, the new Upper Harbour Ammunition Facility (UHAF) was to consist of a jetty (15m by 85m), two mooring dolphins and two small vessel pontoons. We built the new jetty structure by driving forty-two, 40m-long tubular piles into the seabed, working from our floating crane barge. We then placed precast concrete pile caps, 28 precast concrete beams, and 14 fender panels. The structure was completed with in-situ concrete pours to stitch the units together and form the deck.

3,000 casting sockets were then placed into the pre-cast units to allow safe access, for scaffold and walkways to be set up as the works progressed. The facility did not have any land connection, so ensuring the safety of

our employees and the safe transportation of machinery, equipment and materials was a key priority.

We redesigned aspects of the new structure to improve constructability and reduce safety and environmental risks. The pile design was then adjusted to eliminate raker piles, which would have presented major safety concerns due to the high tidal range.

The precast deck design was optimised by incorporating cable ducts into the in-situ concrete. We then made the deck a safer working space during construction by making it a closed structure. We also made the UHAF easier to operate and maintain, by flattening the deck and optimising the concrete mix to increase durability.

HMNB Portsmouth Upper Harbour Ammunition Facility Project successes

The value engineering initiatives we incorporated allowed us to deliver the new UHAF structure one month early and on budget. The DIO Project Manager at the time, Paul Simmonds commented:

“This has been a complex project due to the nature of the requirement, the environment and additional levels of regulation required for explosives facilities. The fact that the UHAF has been completed on time and within budget is testament to the excellent collaborative approach taken between VolkerStevin, the DIO and naval base staff.”

The two-ammunition handling cranes that we installed, meet strict military and explosive handling standards. We worked collaboratively with our specialist designer, Kenz Figee, and technical authority, Houlder, to satisfy the client and its competent assessor. We used lessons learned from the project to install two very similar cranes on a military jetty at Glen Mallan, Scotland.

We achieved a CEEQUAL ‘Very Good’ Whole Project Award—we avoided polluting the harbour and recycled 99% of waste when demolishing the old UHAF structure. Four wind turbines sustainably power the UHAF. The diesel generator is therefore only used bi-weekly during ammunitioning.