quay wall reclamation method statement

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Bantry Inner Harbour Development: Phase 1

Bantry Inner Harbour Development Phase 1 Port of Cork Tender Submission 15 October 2015 BAM Method Statements

Introduction

Prior to any works commencing on site Site Specific Method Statements will be prepared for all the major elements of the work. These method statements will outline precisely how Bam will approach and carry out the works associated with the Bantry Inner Harbour Development – Phase 1 Contract. These method statements will be submitted to the Employers Representative for approval, work will not commence prior to the relevant method statements being approved.

The method statements will be prepared by the Project Manager Collins Connolly and the Site Agent Seamus O’Sullivan, however the various other members of the site management team will be asked to contribute to the relevant sections of the method statements as required. The method statements will be prepared in line with the Works Requirements, Specifications, Guidance Documents and Consultations meetings with various other stakeholders.

While the more specific in-depth method statements will be prepared once we get to site, below are the overall method statements which will outline our general approach and methodology to the Bantry Inner Harbour Development – Phase 1 Contract.

Introduction

This method statement incorporates Bam overall approach for the Quayside Reclamation Works, option 3-variant. Prior to any works commencing on site more comprehensive and detailed, task specific method statements will be prepared by Bam for each element of the works.

Scope of Works

The works will consist of the following:

Proposed Plant

Variant Option Overview

Excavation Works, (Including Causeway Construction)

Quay Wall Construction

Rock Anchoring& Core Filling (N/A for Variant option)

Drainage Works

Services Water & Electricity including connection to Marina

Carpark Pavement Construction

Works Proposals – Option 3

Part 1 Site Specific Method Statements – MS05-3 Quayside Reclamation Works

Quayside Reclamation Works

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Location of the Works

Figure 1: Site Location Map

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Figure 2 – Quayside Reclamation Area Plan View.

Figure 3: Photograph taken looking West along Quayside Reclamation area with the Town Pier in the Background.

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Proposed Plant

Details are listed below of plant and equipment to be utilized in the construction of the Quayside Reclamation Area, including access and egress support to be used in the works.

The details provided are specific to the project. All relating to the construction of the Quayside reclamation area are detailed.

Most of the equipment is BAM owned or will otherwise be hired/ subcontracted.

Item Activity/ Roles Quantity [nos.]

30 ton tracked excavator Revetment construction/placement of dredge material

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Tipper Truck/ Volvo A25 Moving of material on site 1

65t long reach excavator with GPS system & 4t breaker

Dredging of rock and slipway from shore

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Longreach excavator with loading bucket & Grab

Long trucks with stabilised material/ retrieving dredged rock from shore

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250HP separator power pack To run rock hammer 1

135 cfm compressor To run underwater rock hammer 2

Piling Hammer BSP + Vibro Sheet pile installation

Crawler crane 85 tons Piling Handling/Storage area 1

Oxygen/ Acetylene set Pile cutting and preparation 1

Testing Equipment Testing of materials 1

Vibration and noise monitoring equipment

Monitoring the works 1

Welding Plant Temporary works for storage cells on flat top barge

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Safety boat Works over water 1

Lighting Tower Site Lighting 1

Pickup Site attendances 1

Bog mats Protect pavement from damage

Heras Fence Secure the handling and storage area.

Generator Providing power 1

Survey equipment Survey 1

Handrailing Fall protection at water edge

Further equipment is also available from our subcontractors and sister companies in the BAM group.

All mechanical plant will be in good working order and subject to a regular maintenance regime. Only suitably qualified and experienced personnel will be allowed to operate plant and equipment.

All Vehicles will be fitted with reversing beacons and a flashing light and will be directed by a banksman. All plant certification will be checked by the BAM Civil Safety Officer prior to commencing works on site. A register of all plant and equipment checks will be kept on site for the duration of the project.

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Figure 4: Previous Marine works carried out by Bam using Bam Marine Plant

Quayside Reclamation: Variant Option 3: Method Overview: The New Quay wall will be constructed from mass concrete founded at -6.3mAOD, which is below the future dredge level of -6.112m AOD, topped by a precast concrete Quay Wall with an insitu toe stitch anchored into the reclamation area with dead men anchors. As per Figure 5 below.

Figure 5: Proposed Quay wall X-Section

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Excavation Works Stage 1: Causeway construction In order to construct the mass concrete base of the quay wall we must construct an access causeway along the full alignment of the new quay wall. In order to construct the causeway traffic management will be set-up along the N71 and a site access created through the existing masonry quay wall along the roadside.

A causeway will then be constructed with imported aggregates using the newly constructed site access. A geotextile will be placed at low tide along the alignment of the causeway and the imported aggregates placed on top of the geotextile. A 30 ton tracked excavator will be utilised to place and shape the causeway material. The top of causeway level will be at +1.5mAOD, and a minimum of 6m wide working platform on top, ensuring that the there is sufficient working width on the seaside of the cofferdam.

A silt treatment basin with sufficient capacity to store all the silts within the reach of the Bam CAT365 19m long reach excavator will also be constructed using imported aggregates. The silts will be cement stabilised within the basin to form a section of permanent reclamation area. Cement stabilisation & dredging works will be addressed further in greater detail within the dredging method statement.

Note: The Silt treatment basis is shown on the eastern end of the Quaywall construction, but may also be positioned at the western end.

Figure 6: Causeway & Silt treatment Basin

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On completion of the causeway and silt treatment basin, Bam will dredge all overlying silt materials within reach from the causeway and place & treat them in the silt treatment basin where they will be left permanently. Programme of works for this phase is January’16 to end of March’16. This will then ensure that all remaining excavation/dredging works required to complete the Quayside reclamation works will be contained within the causeway.

Dredging & Cement Stabilisation works. Method for Dredging and Lime/Cement stabilisation works will be covered in detail in the Dredging Method Statement.

All Dredging woks completed during January’16 to end of March’16 to facilitate the construction of the Quayside reclamation area will be completed using land based plant. Only the top 1.5m (silts) or so of the seabed directly in front of the newly constructed causeway will be excavated using the Bam 365 long reach excavator. The material will be transported on site using 25ton dump trucks to the silt treatment basin shown in figure 6 above. Here the material will be treated using Cement Stabilisation.

Figure 8: Bam CAT 365 Dredging & Causeway construction in Baltimore

Figure 9: Showing stage 1 of reclamation area & Coffer dam for Pit No. 1

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The volume of dredge material within reach to the front of the causeway will equate to the volume required to fill the treatment basin to +1.5m AOB. Once complete this area will then be the main compound/site access and set down area for the construction of the Quay wall.

For ease of construction the quay wall will be split into 3 sections, each approximately 45m in length. Each section will be constructed within a cofferdam, constructed using PU16 sheet piles 10m long driven to rock head and braced internally. See cross section below.

Figure 10: Cross section through cofferdam for quay wall construction

The material will be excavated from within the cofferdam in stages, using a combination of the 30 ton tracked excavator and a mini excavator. The top wailer and brace will be installed at approximately +1.5m level. Next the underlying silts and gravels will be excavated to -4.0mAOD where the second cross brace and wailer will be installed, excavation can then continue to -6.3mAOD or to rock head whichever is shallower with all excavation risings placed and treated in the quayside reclamation area.

Where rock is encountered higher than -6.3m AOD a rock breaker attached to the 30 ton excavator will be utilised under water to break the rock. The breaker will be fed from a 130cfm compressor to allow it work under water. A minimum formation depth of -6.3mAOD must be achieved to ensure the Quay wall is founded below the future dredge level of -6.18mAOD.

Mass Concrete & Precast wall construction

The mass concrete will be brought up in two layers vertically and three sections along the length of the cofferdam. The bottom layer brought up to -4.5mAOD will allow the -4.0m brace to be removed. The first lift will then be brought up to -1.2m AOD just above MLWS. Note that started bars will be cast into the top pour in order to stitch the precast unit to the mass concrete.

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A set of steel forms will be used to shutter the mass concrete pour and braced off the sheet piles by use of a dive crew, (Note: diving operation will be covered in a separate method statement). Recessed will be formed in the formwork to allow for ladder access points.

The mass concrete will be placed (tremied) under water using an articulated boom concrete pump with additional bagging. To ensure the head of the discharge hose remains within the freshly discharged concrete at all times a diver will supervise the concrete placement.

On completion of the mass concrete the top brace and wailer can be removed and the precast concrete quay wall placed using a crawler crane working from the reclamation area behind, and temporarily supported onto the top surface of the mass concrete.

The precast wall panels will be cast off site and transported to site on articulated lorry and stored on the reclamation area. The units will be lifted into place using the crawler crane from the sheet piling installation. Recessed will be preformed in the precast units for ladder access points. The units will be lifted into position and temporarily supported by the sheet piled wall.

The precast wall will then be stitched onto the mass concrete with a series of steel dowels and an in-situ concrete toe stitch to the backfilled side of the wall. A female connector will be cast into the base pour at this point at 4m ctrs to take the dead men anchors connected once the sheet piled walls have been removed. As per figure 5 above.

To provide dead men anchors, 5m long AZ17 sheet piles will be driven at 4m ctrs approximately 15m behind the Quay wall face and the anchors connected from the base of the wall to a wailer running behind the sheet pile dead men.

Drainage Works

The proposed drainage works for the Quayside reclamation works consist of the following

New 375mm diameter carrier, storm water drain to pick up existing road gullies.

New 225mm diameter carrier, storm water drain to pick up surface water drainage on the Quayside reclamation area.

New 250mm diameter filter, back of Quay wall drainage.

Figure 11: Photo of Quayside reclamation area showing gully outfalls

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New 375mm diameter Carrier:

At present there are 6 no gullies which out fall through the present masonry quay wall into the quayside reclamation area. During the construction of the new quay wall and reclamation area these gullies will be temporarily picked up and the flow diverted away from the works. This temporary diversion will be inspected and maintained regularly.

Opes will then be cast into the new retaining wall inside the existing masonry quay wall to allow a saddle connection to the new 375mm diameter storm drain.

On completion of the reclamation fill area a trench will be excavated and the new 375mm diameter storm water drain laid as per the alignment, levels and grades specified on drawing 16341-2302, and to the typical pipe bedding and trench details on drawing 16341-2304.

There are three no. manholes on the line which will be constructed as per the detail on drawing 16341-2303.

Note: all drainage pipes and manholes will be constructed as per the NRA Series

New 225mm diameter Carrier:

On completion of the reclamation fill area a trench will be excavated and the new 225mm diameter storm water drain laid as per the alignment, levels and grades specified on drawing 16341-2302, and to the typical pipe bedding and trench details on drawing 16341-2304.

There are three no. manholes on the line and four gullies which will be constructed as per the detail on drawing 16341-2303.

Both the 375mm and the 225mm diameter storm water drains will join at manhole SMH03, and pass through a Class 1 By-pass separator, installed as per the manufactures guidelines, before out falling through a check valve in the new quay wall. An outfall pipe will have been cast into the base of the new precast wall to accommodate the drainage outfall.

As per Appendix 5/10, flap valves will be TKV series valves, or similar approved manufactured in HDPE and installed as per the manufactures instructions.

New 250mm diameter filter, back of Quay wall drainage.

On the landside of the new precast L-wall forming the new quay wall a filter drain founded at top of base level will be required to equalise the pore water pressure at the back of the wall.

On completion of the reclamation fill area a trench will be excavated and the new 250mm diameter land drain laid as per the alignment, levels and grades specified on drawing 16341-1306, and to the typical pipe bedding and trench details on drawing 16341-1306.

There will be 6 no. outfalls through the new quay wall, invert level to match LAT (-2.070 ODM), each outfall fitted with a flap valve as per the requirements in appendix 5/10

Note: All drain runs will be tested as per NRA guidelines.

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Services Water & Electricity including connection to Marina

The proposed services to be constructed as part of the Quayside reclamation works consist of the following:

New 100mm diameter PE100 SDRII watermain, including connections to toilet blocks, fire hydrants and pontoon area. Including tie-in of existing.

New foul connection from new toilet block to existing foul sewer.

LV connections including ducting to Toilet Block, Bin store, pontoons and street lighting and entrance barriers. Also includes the construction of MDB and SDB.

CCTV system.

Included in this section also is the construction of the toilet block and Bin store.

Service ducting will commence on completion of the reclamation fill. Ducting lighting & column bases will be installed to accommodate the power, lighting and CCTV requirements as set out on drawing 16341-90101 & 90300. All ducting will be air tested and mandillled as per the NRA specification. Which includes connections to the pontoon area and the town pier.

Bam will liaise with the ESB to coordinate all power connections to the existing network.

A new 100mm diameter watermain will also be installed at this stage and tested as per the specification prior to the hydrants be installed. Again Bam will liaise with Irish water on the connections to the existing main on the town pier.

The foul main connection to the existing sewer will be completed once the fill is completed and prior to the foundations of the toilet block being constructed. Bam will set-up traffic management to complete the foul connection to the existing main under the main road adjacent to the works. Note that an ope will have been left through the new retaining wall for the foul pipe connections.

Construction of Bin Store and Toilets

The Bin store and toilets will be constructed as detailed on drawing 16341-1228 & 1230

Once the ground has been filled to level the foundations will be blinded and a 300mm deep by 900mm wide strip footing will be constructed as per the drawings. Scaffold will be erected for the construction raising of the walls and roof. Opes will be constructed in the walls for the windows and doors.

Fittings, doors and windows will be installed to the new opes. Rendering and painting will be undertaken as detailed on the contract drawings.

All electrical works will comply with IEEE regulations and the electrical system layouts/ switching will be installed as per drawing 16341-91300.

Foulwater drainage will be connected as outlined above.

Carpark Pavement Construction

On completion of all the services in the Quay Reclamation area Bam will commence the Pavement construction. The reclamation fill area will be trimmed to level and compacted with a smooth barrel roller. A minimum depth of 300mm Cl804 will be placed and compacted on a combigrid as specified on drawing 16341-1206, and tested as per the specification. The top of the CL804 will be surveyed and trimmed if necessary prior to being over laid with 75mm of binder course.

Once the binder course is placed to level all ground furniture including gullys, manhole covers hydrant covers etc will be raised to level. Once complete 55mm of wearing course will be placed to the levels and falls shown on the drawings.

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All road markings including parking bays and hatched areas will be lined by a specialist contractor, as per the specification.

Ancillary items such as bollards, ladders etc. The new concrete ring beam and ancillary items will be constructed as per Byrne Looby drawing B13721001, see attached appendix 1.

Once the Precast wall has been completed and anchored, the area on top of the mass concrete will be filled with treated dredge materials up to the underside of the quay wall ring beam. Note that the back of wall drainage will be installed at this point prior to the area being blinded.

Brackets and gangways will be fitted to the outside of the new quay wall for access and egress along the perimeter of the quay

Figure 12: Works at Bantry Town Pier by Bam, showing access gangway and ladder recess points

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The works will progress west to east in direction.

Reinforcement cage for the ring beam will be prefabricated, which will include local thickenings for mooring bollards, and lifted into position and fixed to the starter bars out for the wall. 50mm cover will be provided to all reinforcement. The ring beam will be shuttered and poured as detailed on the contract drawings and Byrne Looby drawing B1372.1001

A Steel Nosing will be fixed to the shutter for the outer ring beam to the levels shown on the drawings. The formwork will be propped from the temporary gangway reinforcement with the use of dywidag bars and nuts. Note: a temporary works design will be in place for the formwork and gangway.

Ladder recesses will be formed whilst shuttering the deck.

The concrete ring beam will be cast using C40/50 XS3 concrete as per the design and will be brush finished and cured for 7 days.

All concrete will be tested for workability on arrival on site and sample cubes will be taken to determine the characteristic 28 day strength.

Joints in the new deck slab will be filled with a two part polysulphide sealant as detailed in the Specification. Mooring t- bars will and twin stag horn bollards will be installed at the locations shown on the drawings. A crane will be used for the installation of the bollards which will be bolted to the pier deck.

Hot dip galvanized toe rails will be cast in the concrete deck at 300mm from the pier edge.

Toe rails will be cast in the pier deck at 300mm from the pier edge.

New galvanized ladders and steel handrails will be bolted to the deck and recessed concrete walls.

Figure 13: Bantry Town Pier construction showing holding down bolts for the mooring bollards. Also showing nosing’s & Pier Kerbing.

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Safety

• Risk assessments have been carried out and are included in the Health and Safety Plan. The Health and Safety Plan is included in section 3 of the submission.

• All work will be carried out in accordance with the Health and Safety Plan for the site.

• The site operates an induction procedure for personnel prior to commencing work on site.

• P.P.E. will be worn by everyone involved on this project at all times to include a minimum of high visibility vest, hard hat, safety glasses and safety boots.

• All plant will be in good working order and equipped with yellow flashing beacons

Programme of Works

Refer to construction program as included in section 2 of the submission.

Quality an Environmental management

The project Quality Plan will be implemented after being approved by the ER and the inspection and test plan will be adhered to rigidly. A copy of the Quality Management Plan will be kept on site. Seamus O’Sullivan will be the person with responsibility for quality control. Site audits will be carried out to ensure compliance with the Quality Plan. Periodic company audits will be carried out to ensure QA standards are being maintained on the project.

All works will be undertaken in accordance with the Site Specific Environmental Management Plan and the Waste Management Plan. These plans have been included in section 5 of the submission. The main environmental impacts and considerations associated with the works are as follows:

• Waste Management: Waste management will be as specified in the site WMP

• Water Pollution: No contaminated water to be discharged into the harbour.

• Noise: All plant and machinery used on site will be serviced regularly to avoid excessive noise. Noise levels on site are not expected to exceed the legal but where necessary, mandatory warnings signs shall be erected informing all when ear protection is required to be worn.

• Protection of Watercourse: The water course shall be protected from pollution, by ensuring that generators, pumps etc are placed in drip trays. Spill kits shall be located adjacent to the watercourse and clearly identified. Spill kits shall also be placed in all machines. Details of procedure for dealing with oil spillages and procedure for protecting water courses are contained in BAM Environmental Management Plan

• Hazardous Substances: All hazardous substance will be stored in the hazardous store and all generators will be placed on a drip tray at all times.

• Washing of concrete trucks to take place at a designated concrete wash out area.

Figure 14: Screenshot of Quayside programme from Main Programme

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