MERSEY GATEWAY BRIDGE PROJECT · 2015. 3. 12. · MER-CJV-REP-TMP-07-510131 1 12 MARCH 2015 1...

MERSEY GATEWAY BRIDGE PROJECT

MERSEYLINK CONSTRUCTION METHOD REPORT SECTION 7 WESTON LINK MARCH 2015

MER-CJV-REP-TMP-06-510131

Construction Method Report Section 7 – Weston Link

FORWARD POINT OFFICE

Document Control Sheet Rev. Status Revision History Date By Check Approved

- PD For Planning Discharge 12 MAR 2015 MM TG SG

Merseylink CJV Forward Point Tanhouse Lane Widnes Cheshire WA8 0SL Tel: +44 (0)1928 785700


FORWARD POINT OFFICE

Table of Contents

1 Introduction ............................................................................................................. 1

1.1 Introduction ................................................................................................................. 1

2 Description Of The Works ...................................................................................... 1

2.1 Road Works ................................................................................................................ 1

2.2 Structures ................................................................................................................... 2

Figure 1 Ineos Chlor Retaining Wall ..................................................................................... 2

Figure 2 Equestrian Bridge .................................................................................................. 5

3 Site Access .............................................................................................................. 5

4 Site Clearance .......................................................................................................... 6

5 Utilities Diversions .................................................................................................. 6

6 Construction Vehicles And Numbers .................................................................... 6

7 Traffic Management ................................................................................................ 7

8 Environmental Issues ............................................................................................. 8

8.1 Construction Environmental Management Plan .......................................................... 8

Appendix A – Support Documents ................................................................................. 9


MER-CJV-REP-TMP-07-510131 1 12 MARCH 2015

1 Introduction

1.1 Introduction

1.1.1 This report describes the construction methods that Merseylink will adopt in order to

construct the new works within Section 7 Weston Link. This will include major elements

such as the contiguous piled retaining wall, an equestrian bridge, associated footpaths

and a new on-slip merge lane within. It will also outline the proposals for the partial

demolition of the existing western expressway over-bridge (Rocksavage West Bridge) at

this junction.

1.1.2 The report augments the information contained in the Construction Methods Report (ref

MER-CJV-REP-TPL-00-5100011) for the entire Project which has already been partially

approved by the local planning authority.

2 Description of the Works

2.1 Road works

2.1.1 Section 7 includes the Western Point Expressway, Western Link (Northbound link) and

the Western Point Expressway junction.

2.1.2 The road works include the construction of a new Western Point Expressway; west to

north bound link slip road; and amendments to the existing Western Point south to north

bound link road. These works include all roadway merge and diverge arrangements to

meet current geometric standards.

2.1.3 The new Western Link road will be constructed to allow a left hand merge and result in

the removal of the existing right hand side merge to the existing Western Link.

2.1.4 The links will be accommodated by single lane slip roads. These works will comprise

modifications to the earthworks and highway alignments and the construction of a new

retaining wall to accommodate the new link road.

2.1.5 The outline construction process is as follows:

Complete main utility water main diversions.



Construct new contiguous piled retaining wall (known as the Ineos Chlor Retaining

Wall)

Construct new equestrian footbridge

Complete new earthworks and associated road works with the slip roads.

Demolish part of the existing Rocksavage West Bridge

Demolish the old western to Central link –(South bound)

Construct a new ramped footpath – equestrian way

2.2 Structures

2.2.1 Section 7 includes two new structures, Ineos Chlor Retaining Wall and the Equestrian

Bridge.

Ineos Chlor Retaining Wall:

2.2.2 This new retaining wall will be constructed with contiguous piles to form a cantilevered

wall. The wall will be faced with insitu concrete. This retaining wall will allow the new

Western Point Expressway to Western Link Road to be constructed.

Figure 1 Ineos Chlor Retaining Wall



2.2.3 The construction sequence is described below:

i. Retaining Wall

Prior to commencing construction of the new wall a pair of 400mm PE water mains

will be directionally drilled from the north side of the wall beneath the existing Western

Point Expressway and to the south side of Rocksavage viaduct.

The water main will also include a section of conventional open cut pipe work to

complete the diversion work. The final connection and transfer of the water supply

from the existing main to the new diversion will be phased during the construction of

the piled wall.

The existing ground and existing northbound link will be filled with suitable material

to form a piling platform to the south side of the retaining wall. The piling rig will be

situated to the south side to ensure that no damage occurs to the existing 600mm

water main and the newly diverted section.

Piling works will commence at the western end of the piled wall and progress towards

the existing water main located within the existing footpath to the south of the Mormon

Church. Prior to continuing with the piling operations the new main will be connected

once the first section of piling has passed the section of drilled pipework. At the time

of writing this report United Utilities are investigating the possibility of making final

connections prior to piling operations

With the water main diversion completed the remaining section of the piling works

can be completed.

The new retaining wall also forms part of the Equestrian Bridge sub structure. With

the substructure completed the new bridge deck can be cast.

The main retaining wall is also clad with a new concrete face.

Upon completion of the structures work the bulk earthworks and road works

operations can commence.

Equestrian Bridge

2.2.4 The bridge is required to carry the existing bridleway over the new link road. The bridge

will have a width of 3.5m to allow for combined pedestrian and equestrian use. The road



below will be a single lane urban all-purpose connector road comprising 2.5m west verge,

3.3m hard shoulder, 3.7m carriageway, 0.3m hard strip and 2.5m east verge.

2.2.5 In order to cross the proposed road, the structure will have a clear span of 12.2m, which

is easily accommodated in a single span. The structure will be provided with a width of

3.5m between parapets to allow for pedestrian and equestrian use. This relatively small

span can be accommodated in a single span reinforced concrete deck founded on a

contiguous piled wall foundation. As this bridge is located in a ‘green field’ site ‘top down’

construction is adopted to minimise the risk of working at height (see 2.2.8 below).

2.2.6 Either side of the west abutment the will be Ineos Chlor Retaining Wall, this will also be

constructed using contiguous bored piling, and will be finished to match the Equestrian

Bridge. Movement joints will be provided between the bridge and the retaining wall.

2.2.7 The approaches to the bridge will generally be formed of earth slopes. However, local to

the ends of the deck a reinforced concrete slab will be provided to act as the supports to

the equestrian parapet. At the west end of the crossing the structure interfaces with the

proposed new Ineos Chlor retaining wall.

2.2.8 Construction of Structure

As noted above, the structure can be constructed in a ‘green field’ site, so there is

considerable flexibility in the construction sequencing. In order to eliminate the risks of

working at height, ‘top down’ construction will be used. An outline sequence for the

structure is as follows:

Remove any soft areas in the existing made ground.

Fill the location of the deck with structural backfill up to bridge soffit levels.

Construct temporary piling platform for Ineos Chlor and Equestrian Bridge abutments.

Install Ineos Chlor retaining wall.

Install bridge abutment piles.

Construct bridge deck.

Carry out the bulk excavation for the link road cutting.

Excavate below the bridge deck down to road finish level.

Install wall facing construct capping beam.



Construct new bridleway route.

Figure 2 Equestrian Bridge

2.2.9 Section 7 also includes the retention of the following existing structures: Rocksavage

Viaduct and Rocksavage West Bridge. These structures are identified in Scheme Road

Layout (sheet 25) - MER-DJV-DRA-HWY-07-301125 rev02. However, a section of

Rocksavage West Bridge is also demolished once the new Western Point Expressway to

Western Link North bound is completed. This existing structure will require careful and

controlled demolition as part of the removal of the existing link road.

2.2.10 Demolition of this and other existing bridge structures on the whole scheme will be

covered in a specific Demolition of Structures CMR and will be issued at a later date.

3 Site Access

3.1.1 Site access will be from the existing carriageway. Safe entry and egress from the working

areas is incorporated into the traffic management regime.



4 Site Clearance

4.1.1 Site clearance will be required before starting the construction works. The site clearance

is detailed on drawing MER-DJV-DRA-HWY-07-302011 rev03.

4.1.2 At Weston Link Junction there will be a need to demolish part of the Rocksavage West

Bridge.

5 Utilities Diversions

5.1.1 There are a number of existing services in the area which will require diverting or

protection during the work. Details for the Ineos Chlor Retaining Wall services protection

can be found in a separate report. (Ineos Retaining Wall Services Protection Report -

MER-CJV-CAL-TMP-07-520388 rev-)

5.1.2 A United Utilities asset, consisting of a 24’’ diameter clean water main must be diverted

due to the re-alignment of the existing junction. A suitable diversion has been agreed with

United Utilities.

5.1.3 There is an existing 18” diameter brine main serving the Ineos Chlor site. Suitable

protection, if required, will be agreed with Ineos Chlor.

5.1.4 There is an existing 500mm (nominal) diameter National Grid high pressure gas pipeline.

The retaining wall has been designed such that National Grid’s requirement for a minimum

3m space between the wall and the pipe is maintained. Vibration from our operations will

be monitored and recorded to ensure National Grid’s limit of 75 mm/s is not exceeded.

6 Construction Vehicles and Numbers

6.1.1 The execution of the Section 7 works will involve a number of wagon movements for both

delivery of materials and plant as well as removal of surplus spoil. This will include

materials to construct the retaining wall comprising:

6.1.2 Approximately 66 HGV material deliveries movements: 2 HGV for drainage materials, 40

concrete mixer trucks for pile installation, 1 HGV for hangers, 3 HGV for scaffolding, 8



trucks for formwork materials, 10 HGV for bent reinforcement, 2 HGV for barriers and

finishings.

6.1.3 Approximately 75 tipper HGV movements will be required for the delivery and collection

of the following plant: 2 compaction equipment (15Tn), 2 piling equipment, 2 excavators,

1 working platforms, 2 cranes, and 5 concrete pump. Approximately 10 vehicle

movements will be required for the delivery and collection of small plant and machinery

not covered above.

6.1.4 For general earthworks there will be 2 excavators, 4 dumpers and approximately 500 HGV

wagon movements for the removal of surplus spoil to adjacent fill areas within the project

boundary.

6.1.5 This section will require a workforce of approximately 35 operatives for the construction

of the infrastructure, the operation to construct the equestrian bridge in its final position

and finishing works. In addition four teams of workers will be needed for the assembly of

the general infrastructure.

6.1.6 A self-contained welfare unit will be provided within the site boundary for occasional use.

Main welfare and messing facilities will be sited at the Vencroft site off Astmoor Road. The

workforce will be bussed to the worksite at the start and finish of work and at main break

times.

7 Traffic Management

7.1.1 The construction of Section 7 works will require the closure of the existing slip roads and

main carriageway in a phased and planned manner. Convenient diversion routes to

facilitate the closures have been identified and agreed with the Traffic Manager. A strategy

has been developed to ensure that the road user will not be required to divert from their

route more than once in any direction of travel. This will ensure that traffic management

arrangements in adjacent sections do not conflict.

7.1.2 To construct the retaining wall and equestrian bridge, the earthworks material in the

existing embankments will need to be excavated and re-used in fill areas on the south

side of the river.



7.1.3 During installation of the piled retaining wall it is required to close the Weston Point

Expressway eastbound off-slip toward the Weston Link in Phase 1, to provide working

space. Phase 2 will require full closure of the Weston Link eastbound off-slip toward

Rocksavage Expressway with a diversion for vehicles travelling toward the M56 using a

new signalised junction at Rocksavage Way. This same diversion will be retained during

Phase 3 works. Phase 4 works will only require single lane closures on the Rocksavage

Expressway. These plans will be agreed through the Traffic Management Group within

the agreed timescales.

7.1.4 Some incidental localised Traffic Management may be required as the works progress in

Phase 1, for such works as service diversions. These TM layouts will be agreed with the

Traffic Manager. All notice periods will be adhered to for the approval of such works.

7.1.5 Pedestrian Management – To construct Phase 1 and 2 of the works the equestrian

bridleway/footpath will have to be temporarily closed since there is no viable alternative

diversionary route. Any other localised temporary diversions of the footpaths will be

surfaced, well maintained with signage and segregation barriers in place. Any diversion

length will be kept to a minimum whilst ensuring the safety of pedestrians is maintained

at all times. These, too, will be agreed with HBC highways authority in advance.

Construction plant and pedestrians will be segregated at all times and warning signage

displayed at all crossing points. Advance notices will be issued for any closure and will

be planned in advance if required later in the construction period.

8 Environmental Issues

8.1 Construction Environmental Management Plan

8.1.1 Environmental issues relating to the work in Section 7 are addressed in the individual

CEMP documents previously submitted to the local planning authority. The following

Management Plans are relevant to the construction activities identified.

Pollution Prevention including Traffic Management and Water Quality

Waste

Biodiversity, (particularly Eco 8 Great Crested Newts)

Noise and Vibration

Air Quality



Appendix A – Support Documents

General

Site Clearance - MER-DJV-DRA-HWY-07-302011 rev03

Retaining wall

Ineos Chlor Retaining Wall – GA Sheet (1 of 3) - MER-DJV-DRA-STR-07-349101 rev07



Equestrian Bridge

Equestrian Bridge Abutment Details - MER-DJV-DRA-STR-07-346310 rev03

Equestrian Bridge GA (sheet 1 of 2) - MER-DJV-DRA-STR-07-346101 rev06

Equestrian Bridge GA (sheet 2 of 2) - MER-DJV-DRA-STR-07-346102 rev05

Traffic Management

Section 7 TM Phase 1 - MER-CJV-DRA-TRA-07-501336 rev-




Weston Point Diversion - MER-CJV-DRA-TMP-07-980712 rev-

Weston Point Diversion Junction Details - MER-CJV-DRA-TMP-07-980711 rev-

Services Protection Report

Ineos Retaining Wall Services Protection Report - MER-CJV-CAL-TMP-07-520388 rev-

MERSEY GATEWAY BRIDGE PROJECT · 2015. 3. 12. · MER-CJV-REP-TMP-07-510131 1 12 MARCH 2015 1...

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