v4 crossing phase 2 junction 4 milton keynes western ... · v4 crossing phase 2 junction 4 milton...

V4 Crossing Phase 2 Junction 4

Milton Keynes Western Expansion Area

Ringway

Phase 2 Feasibility Study

B2128801/ FSP/PH2 JUNCTION 4 | 0

17th December 2015

Feasibilit y Study Propos al Ringway


B2128801/FSP/PH2 J4 rev0 i

V4 Crossing Phase 2 Junction 4, Milton Keynes Western Expansion Area

Project no: B2128801

Document title: Phase 2 Feasibility Study

Document No.: B2128801/FSP/PH2 JUNCTION 4

Revision: 0

Date: 17th December 2015

Client name: Ringway

Client no:

Project manager: Ian Coddington

Author: Dan Lockwood

File name:

Jacobs U.K. Limited

1180 Eskdale Road

Winnersh, Wokingham

Reading RG41 5TU

United Kingdom

T +44 (0)118 946 7000

F +44 (0)118 946 7001

www.jacobs.com

© Copyright 2015 Jacobs U.K. Limited. The concepts and information contained in this document are the property of Jacobs. Use or copying of

this document in whole or in part without the written permission of Jacobs constitutes an infringement of copyright.

Limitation: This report has been prepared on behalf of, and for the exclusive use of Jacobs’ Client, and is subject to, and issued in accordance with, the provisions of the

contract between Jacobs and the Client. Jacobs accepts no liability or responsibility whatsoever for, or in respect of, any use of, or reliance upon, this report by any third party.

Document history and status

Revision Date Description By Review Approved

0 17/12/2015 1st issue DL CD IC


B2128801/FSP/PH2 J4 rev0 ii

Contents

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

1.1 General ........................................................................................................................................................ 1

1.2 Study area and objective ............................................................................................................................. 1

1.3 Approach ..................................................................................................................................................... 2

2. Background Information ........................................................................................................................... 3

2.1 Information Gathered................................................................................................................................... 3

2.2 Design Criteria / Standards ......................................................................................................................... 4

2.3 Design assumptions .................................................................................................................................... 7

2.4 Information Used For Design Drawings ...................................................................................................... 4

3. Feasibility Assessment ............................................................................................................................. 5

3.1 Options considered ...................................................................................................................................... 5

3.2 Preferred option selection ........................................................................................................................... 5

3.3 Feasibility study limitations .......................................................................................................................... 7

4. Key Risks ................................................................................................................................................... 9

5. Recommendations and further works ................................................................................................... 10

5.1 Recommendations ..................................................................................................................................... 10

5.2 Further works, investigation and surveys .................................................................................................. 10

6. References ............................................................................................................................................... 12

6.1 Ordnance Survey Mapping ........................................................................................................................ 12

Appendix A. Gap Analysis

Appendix B. Site constraints plan

Appendix C. Option A Concept Drawing and Option B Concept Drawing

Appendix D. Option A Section A-A

Appendix E. CDM Designers Risk Assessments

Appendix F. Project Risk Register


B2128801/FSP/PH2 J4 rev0 1

1. Introduction

1.1 General

In July 2015 Jacobs UK Ltd was commissioned by Ringway to carry out a feasibility study for a new subway in

Milton Keynes, for Milton Keynes Council (MKC). The proposed subway will link the planned Western

Expansion Area 11 (WEA 11) Redway routes on the south side of the V4 Watling Street to the existing (MKC)

routes on the north side of the road.

Feasibility Report B2128801/FSP/JUNCTION 28 issued 04/09/2015, discussed the feasibility of crossings

located either side of Junction 28. Further works identified in section 5.2 of the above report, included the

requirement to carry out pedestrian and cyclist surveys to confirm desire lines. A review of the desire lines has

consequently been conducted by UDLA who stated that the proposed subway crossings were sited too far away

from the desire lines and should be brought closer to the Kiln Farm roundabout, Junction 4, to aid the transition

of pedestrians across the V4.

MKC discussed the cost variance of constructing so close to the roundabout and stated that a further feasibility

was required to ascertain the differences of Cost/Benefits/Constraints. This report discusses the feasibility of a

V4 crossing adjacent to Kiln Farm roundabout – Junction 4.

1.2 Study area and objective

Prior to this study an approximate crossing location was identified by the client, west of and as close to the

Junction 4 roundabout as possible, but further work was required to understand the site constraints and fix the

subway position.

The key objective of this report is to provide alternative concept options for cost benefit analysis compared with

options presented in phase 1 to determine the most suitable location for the subway to allow the project to

progress to preliminary and detailed design phases, and ultimately to construction.

The location of Junction 4 – Kiln Farm roundabout is highlighted on the mapping extract below:

Galley Hill Roundabout

Junction 4 -Kiln Farm

Roundabout Western Expansion

Area 11

J28


B2128801/FSP/PH2 J4 rev0 2

1.3 Approach

Our approach has been to locate subway crossings to a suitable position taking into consideration the desire

lines confirmed by UDLA, the main constraints such as the existing topography and road layout, the position of

the existing and future Redways routes, the existing utilities, the existing highway boundary and any other

relevant information that could influence the selection process (e.g. proposed highways improvement at junction

28). As part of this study the following steps were carried out:

• Existing data review, gap analysis and constraints identification

• Option generation and assessment (2 options – Option A and Option B)

• Site visit and Client Meeting

• Additional option generation and assessment.

• Preferred option selection

• Concept design of the preferred option

1.4 Deliverables

The following drawings and documents have been prepared as part of this report:

• Gap Analysis – provided in Appendix A

• Site Constraints Plan - (Drawing No. B2128801-J4-0001) – provided in Appendix B

• Option A and Option B Concept General Arrangements - (Drawing No. B2128801-J4-0002 and

B2128801-J4-0004) – provided in Appendix C

• Option A Section A-A - (Drawing No. B2128801-J4-0003) – provided in Appendix D

• CDM Designers Risk Assessment – provided in Appendix E

• Risk Register – provided in Appendix F


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2. Background Information

2.1 Information Gathered

The following historic information has been provided by MKC and Ringway:

• MKC Standards, including details for Redways and Footways

• Existing topographical survey data

• C2 Statutory records

• Details of proposed new utility company services

• Trench reports from ground investigation works

• Designs for the WEA 11 housing development being constructed by Barretts

• Archaeology information

• Borehole records

• Details of ‘Lessons Learnt’ from a previous scheme (Pinch point scheme)

• Previous MKC scheme drawings

• Ecology reports

Further to the above the Jacobs project team conducted a site visit on the 7th December 2015

A gap analysis was carried out on the above supplied data and subsequently missing data. Results of this gap

analysis are provided in Appendix A.

A review of the above supplied data was undertaken and used to produce a constraint plan to inform this

feasibility study. The constraint plan is provided in Appendix B.


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2.2 Design Criteria / Standards

The Milton Keynes Council (MKC) design brief provided specific design requirements; the following are the

relevant ones at this feasibility stage:

• The client specified the use of ABM Europe to fabricate the modular subway, with the chosen

construction method being pre-formed standard design modular sections.

• Internal dimensions of the subway structure are minimum of 8.5m in width and 2.7m in height from

finished surface level.

• Sight distances of 4.0m should be provided at corners and changes of direction. To determine visibility

requirements pedestrians are to be assumed to be 0.4m away from an adjacent vertical wall. Inside

corners are to be rounded off to a radius of 4.6m to meet this requirement.

• Use of Milton Keynes Council standard details for Redways and footways.

In addition to the above requirements, Design Manual for Roads and Bridges (DMRB) TD 36/93 (Subways for

Pedestrians and Pedal Cyclists Layout and Dimensions) was used to design the subway layout.

2.3 Information Used For Design Drawings

Design development and drawings have been produced using the following provided information:

Supplied by MKC;

� “Redway table.dwg” – Location of Redway

� Ordnance survey Information

� “Area 11 survey.dwg” – Topographical survey information (2D only)

� “Adopted Highways.dwg” – Highways Boundary

� “MKS UG services.dwg” – Location of services taken from Historic C2 enquiries

Supplied by Barratts;

� “Highway-outline.dwg” – Location of proposed Junction 28

� “Site Layout Plan.dwg” – Development South of Watling Street

� “8482-147B, A11 Constraints Plan.dwg” – Ecology Information

Supplied by Anglian Water;

� As Laid drawings – to determine interpolated Level of 900mm diameter Water Pipe

Jacobs Project Team Site visit;

� Approximate Substation location


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3. Feasibility Assessment

3.1 Options considered

Following a review of the site constraints and design criteria, including desire lines, two possible locations were

identified. These were:

• Option A: Subway to be located 50m from the centre of Kiln Farm roundabout - Junction 4, crossing the

westbound arm of Watling Street.

• Option B: Subway to be located 25m from the centre of Kiln Farm roundabout - Junction 4, crossing the

westbound arm of Watling Street.

Approximate locations of the two options are highlighted on the mapping extract below. The proposed new

Junction 28 roundabout has not yet been constructed.

3.2 Preferred option selection

Following initial assessment it was concluded that a subway located approximately 50m west of Junction 4

(Option A) would be the most suitable, as it minimises the length of the subway underpass span, required

retaining walls and the impact to the 900mm diameter water main, compared with other locations adjacent to

Junction 4.

Option B

Option A

Planned J28 Roundabout

Galley Hill Roundabout

Junction 4 -Kiln Farm

Roundabout


B2128801/FSP/PH2 J4 rev0 6

Following discussions with MKC on 7th December 2015 it was agreed that a second option (Option B), located

25m from the centre of Junction 4 roundabout reducing the impact further on the desire lines, should be

considered as a comparison to option A.

It was agreed that the 2 options (referred to as Option A and Option B) be considered for concept design, but

only a General Arrangement drawing should be produced for Option B. As-built data for Junction 4, additional

trench survey and revised utility locations were requested; however they could not be sourced by MKC within a

reasonable timeframe to be considered. It was therefore agreed that rather than delay the project further, the

concept design should progress based on the information available.

The table below provides a breakdown of the required infrastructure related to each option.

Option A Option B

Subway span 22m 29m

Length of retaining wall

required 452m 476m

Length of Redway

realignment required 305m 330m

Desire Lines impact

Distance of underpass from the

centre of roundabout is

approximately 50m

Distance of underpass from the centre of

roundabout is approximately 25m

Impact to utilities and

substation

(excluding the 900mm Ø

Anglian Water pipe,

intermediate gas main and

badger tunnel)

Similar impact (diversion required

at both locations)

Survey data is required to confirm

the location and level of these

services and structures.

Similar impact (diversion required at both

locations)

Survey data is required to confirm the

location and level of these services and

structures.

Impact to 900mm Ø Anglian

Water pipe

(Anglian Water approval

required)

No impact to water pipe assuming

the following proposal is accepted

by Anglian Water.

1 in 20 Redway slope from

underpass with an 850mm

minimum cover (including 225mm

reinforced concrete slab) over the

pipe section.

Diversion required to provide a 1 in 20

Redway slope from underpass.

An alternative option which does not

requiring diverting the water main and still

provides 850mm minimum cover

(including 225mm reinforced concrete

slab) over the pipe section, would require

a 1 in 11 Redway slope to be accepted.

This option is not compliant with Disability

Discrimination Act (DDA) or DMRB and is

therefore not recommended.

Intermediate gas main and

badger tunnel

Potentially lower impact

(The Redway slope from the

underpass at this location will

provide greater cover then option

B, potentially reducing the extent

of diversion)

Potentially higher impact

(The Redway slope from the underpass at

this location will provide less cover then

option A, potentially increasing the extent

of diversion)

Impact to Millers Way at

grade crossing

Approximate 31m diversion

required or additional subway

considered

Approximate 66m diversion required or

additional subway considered


B2128801/FSP/PH2 J4 rev0 7

Option A and B concept design is included in Appendix C, Option A’s Section A-A included in Appendix D and

designer risk assessment in Appendix E.

3.3 Feasibility study limitations

All design work has been based on the data provided by Ringway and Milton Keynes Council. These were

assumed to be satisfactory and no verification works were carried out as part of this commission.

Topographical survey was historic and out of date in places.

The utilities records and data provided were historic and out of date in places.

During the site visit on 07/12/2015, it was noticed that a new substation has been installed on the north side of

Watling Street adjacent to Junction 4, for which no information has been provided. This is likely to impact upon

the subway design and construction.

A 900mm Anglian Water pipe is located to the south of Watling Street with a 3.5m easement from the centreline

of the pipe. It has been assumed that a minimum 850mm minimum cover including a 225mm reinforced

concrete slab above the easement is sufficient and needs to be confirmed with Anglian Water.

As built information for the existing surface water drainage network was not supplied.

It was also assumed that the impacted utilities along Watling Street will be raised and diverted to a 2m wide side

verges. This will be subject to agreement with the statutory undertakers. At this stage no contact were made to

engage formally the statutory undertakers.

The brief highlighted the possibility of an asbestos cement water main, which was confirmed by the additional

trial holes carried out in August 2015. No further asbestos survey was carried out as part of this feasibility study.

This feasibility study did not cover drainage issues or structural design, which are to be dealt with at a later

stage of the scheme development. The use of ABM fabricated modular subway structured units is specified, but

ABM design criteria are yet to be confirmed. The structures are designed to comply with Design Manual for

Roads and Bridges (DMRB) standards.

Landscaping issues and lighting provision were not covered as part of this study and will be addressed at a later

stage of the scheme development.

No information was provided regarding ground investigations (water levels, land contamination, pavement

construction or California Bearing Ratio).

Land outside of the highway boundary will be dealt with as part of Section 38 work, which is outside the scope

of this study.

The ‘at grade’ crossing on the northern arm of Junction 4 with Millers Way will either require diversion or an

additional subway to be considered. Design associated with the ‘at grade’ crossing does not form part of this

study.

Construction cost estimate was not provided as it was outside the scope of this study.

3.4 Design assumptions

All design work has been based on the data provided by Ringway and Milton Keynes Council. These were

assumed to be satisfactory and no verification works were carried out as part of this commission.

1 in 2 slopes were assumed at this stage pending confirmation following geotechnical investigations. This

provided the benefit of minimising the earthworks footprint and keeping the proposal within the highway

boundary. Where this is not possible retaining walls will be utilised.


B2128801/FSP/PH2 J4 rev0 8

1 in 20 slopes were used to design the access ramps, however, landings were not provided as instructed by

MKC as these would create a “take off point” for cyclists. This is a non-compliance as design standards (TD

36/93 – section 5.5) states that landings should be included for changes in elevation greater than 3.5m, which

the proposed subway will have.

It was also assumed that impacted utilities will be raised and diverted to a 2m wide side verge either side of the

road to maintain the 900mm cover above the subway. This will be subject to agreement with the statutory

undertakers. The statutory undertaker details highlighted an asbestos cement water main running down the

south side of Watling Street, which will also require diverting. This report has not undertaken any condition

survey of the pipe or asbestos survey and assumes that it can be diverted.

This feasibility study does not cover drainage issues or structural design, which are to be dealt with at a later

stage of the scheme development. It was assumed that ABM Europe modular subway structure will be used

and a system of pump and pipes will be required to assist with surface water drainage. It was also assumed that

the ground water level (GWL) is not a concern. No GWL information is available and this assumption will need

to be confirmed.

It was assumed that land outside of the highway boundary will be dealt with as part of Section 38 work, which is

outside the scope of this study.

This feasibility report has not sought confirmation as to whether relaxations can be applied to the Anglian Water

easement. For Option A it has been assumed that a 850mm minimum ground cover including a 225mm

reinforced concrete slab above the water pipe is sufficient, however this requires approval from Anglian Water.

For Option B the 1 in 20 Redway slope will require the 900mm diameter Anglian Water pipe to be diverted to a

lower level.

For both options the 8” Cast Iron Intermediate Pressure gas main and badger tunnel will need to be diverted.

It is likely the new Substation and connecting ductwork, located on the north side of Watling Street adjacent to

Junction 4, will impact both the proposed design options. No information has currently been provided. Therefore

for this report it has been assumed that the Substation and connecting ductwork can either be relocated or

diverted.

It is assumed the ‘at grade’ crossing on the northern arm of Junction 4 with Millers Way will either be diverted or

an additional subway considered.


B2128801/FSP/PH2 J4 rev0 9

4. Key Risks

Following completion of the Feasibility Study, the main project risks are considered to be:

• Gaps in the current project data – Results of additional surveys/information provided could be

unfavourable and lead to design changes with cost and programme impact. Collection of data may also

lead to programme delays.

• Service diversions are required – This will be subject to agreement with the statutory undertakers, could

increase the project cost and may have programme implications.

• ABM design is specified. ABM design criteria’s are yet to be confirmed. Also to be confirmed is that

these structures are designed to Eurocode. This could lead to departures from standards with cost and

programme implications.

• There has been no liaison with the Technical Approval Authority (TAA) for the proposed structure. The

requirements that the TAA may advise as regards to the design and check category in the Approval in

Principal (AIP) could impact on the programme.

• Archaeology is a potential risks and so is the coordination with an external Ecology consultant. Both

could impact on cost and programme.

• Service diversion may be required for the new 900mm water main maintained by Anglian Water (AW),

should AW not agree to the proposed 850mm minimum cover including a 225mm reinforced Concrete

slab to protect the pipe. This will increase the project cost and may have programme impact

• There is a potential risk that the diversion of Asbestos Water Main to the south of Watling Street might

not be possible. This would result in further design iterations and will increase project cost and impact

programme.

• A new sub-station has been installed on the north side of Watling Street adjacent to Junction 4. No

information is currently available regarding substation and any related ductwork. Service diversions will

likely be required resulting in additional cost and programme delay. It is not possible to assess the

impact without further information.

• A badger tunnel has been identified which will require diversion which will impact both cost and

programme.

• Other ecology impacts are unknown at both locations and could impact the proposed designs affecting

project costs and programme.

• Impact upon the existing Redway at Millers Way. The ‘at grade’ crossing will either require diversion or

consideration of an additional subway.

The project Risk Register has been updated following the Feasibility Study and is provided in Appendix F.


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5. Recommendations and further works

5.1 Recommendations

Based on the analysis of site constraints including desire lines, site visits and discussion with Milton Keynes

Council to ensure local knowledge was taken into consideration, both Option A and Option B were deemed

feasible.

Option A is considered the preferred option as it reduces or eliminates the associated costs of diverting the

900mm diameter Anglian Water pipe and provides minimal deviation from the identified desire lines. Option A

also requires a 24% shorter subway span, requires 5% shorter retaining wall length and 8% shorter Redway

realignment length providing significant cost savings. It also impacts less on the existing at grade crossing on

Millers Way then Option B. It is recommended that MKC make an early decision with regards to which option to

proceed with to avoid any delays and abortive work.

Liaison with key stakeholders, including utility companies, is recommended to ascertain an early response with

regard to proposed service diversions. Specifically early correspondence from Anglian Water regarding the

proposed 850mm minimum cover and 225mm reinforced concrete slab above the 900mm diameter water main

is recommended to avoid delay to the project. It is also recommended that an early decision regarding potential

realignment of the bridleway is required to avoid further delays and abortive work if Option A is progressed

further.

To enable the project to develop further, the project team will require more information. Additional data required

has been identified and listed below in section 5.2. It is recommended that the Client seeks to commission

additional surveys as soon as possible to avoid project delays.

It is also recommended that further preliminary design works be undertaken, with greater consideration given to

highways, structural and drainage design issues. This will enable an initial estimate of construction costs.

Jacobs have provided a proposal for preliminary and detailed design works for the project.

5.2 Further works, investigation and surveys

Further works are required to confirm our assumptions in section 2.3 and resolve the limitations highlighted in

section 3.3. The list below identifies the relevant investigation / surveys necessary to inform the design process.

This list is not exhaustive and could change depending on findings as the design progresses:

• As built records for Junction 4 and Western Expansion Area 11 development to the south of Junction 4,

including updated highway boundary within the development.

• Topographical survey information from Junction 4 roundabout and approx. 200m North along Millers

Way.

• Trial Hole/Trench Surveys at proposed subway locations.

• Details of Badger Tunnel Construction.

• Make contact with Anglian Water to gain early correspondence regarding relaxations to the 900mm

diameter Water Pipe easement.

• Survey to confirm location and levels of new substation and related ductwork.

• As built records of the existing drainage and highway networks affected as also required.

• Geotechnical investigations are required to confirm the use of 1 in 2 slopes, suggest likely foundation

design for the structure and highlight any contamination if present.


B2128801/FSP/PH2 J4 rev0 11

• Utilities mapping of the study area is required to identify impacted utilities. This will also help when

engaging the affected statutory undertakers, which should be done as early as possible to avoid

unnecessary delays and costs due to diversions.

• The brief highlighted the possibility of an asbestos cement water main. Further investigation is required

to fully locate it and if applicable an asbestos survey carried out.

• Carry out a drainage survey if necessary and progress the drainage design. Details of existing ground

water levels are required.

• Approval for Departure from TD 36/93 to omit the need for landings and the potential departure for

using 1 in 11 slopes for Option B, should the diversion of the Anglian Water 900mm diameter pipe not

be acceptable.

• Progress the structural design and confirm suitability of ABM modular subway.

• Liaison with Technical Approval Authority (TAA) for structural design Approval in Principal (AIP)

• Ecology appraisal and subsequent surveys as required.


B2128801/FSP/PH2 J4 rev0 12

6. References

6.1 Ordnance Survey Mapping

Mapping used within this report and the drawings provided in the appendices is reproduced from Ordnance

Survey material with the permission of the Ordnance Survey on behalf of the Controller of Her Majesty’s

Stationary Office © Crown copyright and database rights 2015 OS [100019593]. Unauthorised reproduction

infringes Crown copyright and may lead to prosecution or civil proceedings.


B2128801/FSP/PH2 J4 rev0

Appendix A. Gap Analysis

Comment

no.

Discipline By Date raised Comment

1 Highways PT 30/07/2015 Topo survey information for Junction 4 - Site 11 is only in 2D

2 Highways PT 30/07/2015 No survey information north of existing Redway (north of Watling Street)

3 Highways PT 30/07/2015 C2 info from Virgin indicates something in Northern Redway

4 Highways PT 30/07/2015 C2 info from Cable and Wireless indicates something in Northern

Redway

5 Highways PT 30/07/2015 C2 info from BT Openreach is very basic. Some corrupted files. Indicates

ducting in northern Redway - nothing on GPR. Indicates ducting in

southern verge, GPR shows 3 separate groups of ducts totalling 17 No.

100 dia. No mention of Fibre Optic cables. No accurate location, size &

depth information except as shown in Trench Report.

6 Highways PT 30/07/2015 C2 Street Lighting information is corrupted. Have assumed location on

south verge, based on GPR survey information based on Trench Report

7 Highways PT 30/07/2015 C2 info from Scotia Gas indicates an intermediate pressure gas pipe

running across the field south of Junction 28. No size or depth

information, except in Trench Report.

8 Highways PT 30/07/2015 Good As Built information relating to 900mm dia Water Main. Information

relating to Asbestos Cement Water Main sketchy, No accurate location,

size & depth information except as shown in Trench Report.

9 Highways PT 30/07/2015 C2 info from Western Power relates to north of Watling Street only

10 Highways PT 30/07/2015 MKC XREF 19723.dwg.is large but has 20 No. unreferenced and not

available utilities xrefs. GPR results not consistent with Trench Report

11 Highways PT 30/07/2015 MKS UG Services.dwg taken from 19723, but reduced to suit Developer’s

needs.

12 Highways PT 30/07/2015 MKS UG Services (JJG amended).dwg taken from 19723, but reduced to

suit Developer’s needs. (lots of unnecessary hatching)

13 Highways PT 30/07/2015 Approved design for Junction 28 required.



14 Highways PT 30/07/2015 Xrefs noted in Comments 10/11/12. GPR survey was not continued

westwards beyond end of proposed Junction 28, ( between CL levels

92.93 & 92.97. 479802.484, 239585.743) and no services are shown

beyond this point

THE NOTES ABOVE RELATE TO JUNCTION 28 SUBWAY PHASE 1 OPTIONS, BUT ALSO RELATE TO JUNCTION 4 SUBWAY

PHASE 2 OPTIONS

15 Highways PT 03/12/2015 No survey information for Millers Way, north of splitter island on

northbound arm of Junction 4 roundabout, on Watling Street.

16 Highways PT 03/12/2015 No as built information for Barrett's Development south of Junction 4,

including badger tunnel dimensions and new Highway Boundary.

17 Highways PT 03/12/2015 No road drainage information

18 Highways PT 03/12/2015 Since topo survey and C2 searches were undertaken, a new sub-station

has been installed on the north side of Watling Street adjacent to

Junction 4. No information available regarding sub-station and any

related pipe/ductwork.



Appendix B. Site constraints plan



Appendix C. Option A Concept Drawing and Option B Concept Drawing



Appendix D. Option A Section A-A



Appendix E. CDM Designers Risk Assessments

S WI 05 Attachment 7.1

DESIGN HAZARD ELIMINATION AND RISK REDUCTION (HE & RR) FORM – Rev. 1, April 2007

Project name: V4 Crossings WEA J4 & 25 Feasibility Study Phase 2

Design stage: Feasibility Study Engineering Discipline: Civil - Highways Structure: Subway Junction 4

Project No: B2128801/J4 Doc. Ref.: Revision: 0 Prepared by: D Lockwood Date: 09/12/2015 Checked by: C Dixon Date: 10/12/2015

Ref. Phase C/M/D/UaW

Activity Potential Hazards Person(s) at Risk

RR H/M/L

Design Measures to Eliminate Hazards

Design Measures to Reduce Risk

Residual Risk (to inform construction teams)

Included on Drawing No(s). or other doc. (give

ref.)

A – 001

UaW Access Ramp Public / Wheelchair user having difficulty climbing slope gradient

Public M

Slopes have been designed to meet DDA compliance and DMRB TD 36/93 (1 in 20 slopes provided)

DMRB TD 36/93 states that landings should be provided for an elevation change of greater than 3.5m. MKC have advised they do not want to meet this requirement as this does not fit the philosophy of the existing subways in MK

None

A – 002

UaW Speed Restriction of access ramp

Cyclists traveling at excessive speeds, causing injury to themselves or other users

Public M Cannot be Eliminated

Minimum radius of 4.6m has been followed (DMRB TD36/93 of 4.6m) providing a stopping sight distance of 4m. Cyclists would need to slow down to navigate this bend DMRB TD36/93 states that staggered barriers should be included to reduce cyclists speed to less than 10Km/h. MKC stated that they do not want staggered barriers as this does not fit the philosophy of the existing subways in MK Slopes have been designed to meet DDA compliance and DMRB TD 36/93 (1 in 20 slopes provided)

None

A – 003

UaW DDA compliant

Not achieving DDA compliance resulting in limited or no access for disabled users

Public M

Red routes and subways to be a minimum of 3m wide. (MKC standard)

Minimum radius has been followed from DMRB TD36/93 of 4.6m, providing a stopping sight distance of 4m


DMRB TD 36/93 states that landings should be provided for an elevation change of greater than 3.5m. MKC have advised they do not want to meet this requirement as this does not fit the philosophy of the existing subways in MK

None

A – 004

UaW Pedestrians, Cyclist using access track

Collision of users Public M Cannot be eliminated

Minimum radius has been followed from DMRB TD36/93 of 4.6m, providing a stopping sight distance of 4m. Users would be likely to approach these bends with caution DMRB TD36/93 states that staggered barriers should be included to reduce cyclists speed to less than 10Km/h. MKC stated that they do not staggered barriers as this does not fit the philosophy of the existing subways in MK


None

A – 005

C / M / UaW

Earthworks Users falling down earthworks from existing ground level to Redway

Maintenance, Operatives, Public

H

Slopes designed as 1 in 2 to minimise extent of construction boundary and slips, trips and falls on embankments

None None

A – 006

C / M / UaW

Vehicles falling off edge of carriageway

Vehicles or users falling from road down to subway level

Maintenance, Operatives, Public

H

Parapets to be installed above subway to prevent vehicles coming off the road above

None None

A – 007

C / M / D / UaW

Drainage of subway Flooding of subway Operatives and Public

M Cannot be eliminated

Sump to be provided at one or both ends of subway to collect surface water. Sumps to be pumped into network drainage

None

A – 008

C / M / D

Excavation / Earthworks

Clash with services / electrocution, explosion, flooding and interruption of services

Maintenance Operatives

H Cannot be eliminated Design carried out to minimize interference with existing underground services

Principal Contractor to review existing service drawings to identify potential areas of conflict

A – 009

C / M / D

Excavation / Earthworks Working in close proximity to Gas Chamber and Pipeline

Operatives H Cannot be eliminated Cannot be reduced

Contractor to undertake inspections to confirm pipeline location prior to works. Ensure appropriate PPE and material storage is provided

A – 010

C / M / D

Excavation / Earthworks Disturbance/work in close proximity to Asbestos Cement Pipelines

Operatives H Cannot be eliminated Cannot be reduced

Contractor to conduct trial holes at proposed location to confirm the presence of asbestos, and ensure appropriate PPE and material storage/removal procedures in place

A – 011

C / M / D

Excavation / Earthworks Contaminated land Maintenance Operatives

M Cannot be eliminated Cannot be reduced Contractor to undertake GI prior to works and ensure appropriate PPE and material storage is provided

A – 012

C / M / UaW

Working adjacent to live traffic

Risk to drivers, general public, cyclists and workforce from conflict during construction

Operatives, Public

M

MKC have confirmed that a full road closure including the red route will be undertaken during construction. Therefore removing this risk.

None

Principal Contractor’s Traffic Management measure to be deployed in accordance with Chapter 8 of the traffic signs manual by a competent contractor

A – 013

UaW Using subway at night / low light conditions

Unable to use subway due to limited lighting at night time/ increased risk of collision/trips from users

Public M Lighting in the subway to be provided

None None

A – 014

C / M / UaW

Concurrent site activities from various contractors

Risk to operatives and public from uncoordinated works with other contractors leading to injury

Operatives, Public

M Cannot be eliminated Subway and earthworks has been designed to minimise construction boundary

Principal Contractor to liaise with MKC and developers on adjacent sites to co-ordinate programme/works

A – 015

C / D Lifting of ABM modular units

Lifting of ABM modular units Operatives M Cannot be eliminated

Lifting plan to be produced.

ABM modular units to have lifting hooks or lifting points.

Correcting lifting strapping to be use as per lifting plan.

Principal Contractor to review lifting plan, TM plan and ensure units are providing with lifting points

A – 016

C / M / D

Excavation / Earthworks Working in close proximity to substation

Operatives H Cannot be eliminated

Cannot be reduced at present. Further works recommended establishing cable locations. Once known design is to be amended to reduce impact

Contractor to undertake inspections to confirm cable location prior to works. Ensure appropriate PPE and material storage is provided

Phase Severity of Injury Probability (Prob.) Risk Rating (RR) Hierarchy of Mitigation

C = Construct H: Major, Fatal or long term disabling injury or illness. H: Highly likely

Pro

b.

(LM

H) M H H Note – the purpose of Risk Rating is

to determine which risks are significant. It is a subjective process,

not an absolute or precise determination.

1. Eliminate hazard (design out)

M = Maintain / Clean M: Moderate injury or illness M: Likely event L M H 2. Reduce risk at source (amend design)

D = Demolish and/or Adapt L: Minor injury/ illness L: Possible L L M 3. Provide risk information (add to design)

UaW Use as Work[place

Severity (LMH)



Appendix F. Project Risk Register

Phase 2 V4 Crossing J25 & V4 Crossing J4


Project Risk Register

Rev3 11/12/15

B0000000 FSP2

Risk Likelihood (A) 1-5

Impact (B) 1-5

Risk Rating = AxB

Max 25 Min 1

Mitigation Plan Owner Revised Likelihood

(C) 1-5

Mitigated Risk

Rating

Technical

Gaps in current project data. Results of additional surveys/information provided could be unfavourable and lead to design changes. Collection of data may lead to programme delays

3 5 15 Feasibility study has identified additional surveys/investigations required for future design phases through gap analysis. Actual site investigations to be commissioned by Ringway. Assumptions made due to limited/inadequate data to be clearly stated in deliverables. Deliverables to include design risk and design issues logs

Jacobs / Ringway / MKC

1 5

Service diversions are required. This will require liaison with service providers, will increase the project cost and may have programme impact

5 4 20 Feasibility study has identified anticipated service diversions MKC to undertake early engagement with service providers Regular stakeholder engagement, Jacobs & Ringway to provide input where required

MKC 5 10

At J4 service diversion may be required for the new 900mm water main maintained by Anglian Water (AW), should AW not agree to the retaining wall solution. This will increase the project cost and may have programme impact

3 5 15 Issue identified during Feasibility Study Cross section showing proposed retaining wall option supplied to MKC to facilitate discussion with AW MKC engaging with AW at early stage to mitigate programme delay and understand potential cost if diversion is required

MKC 2 10

ABM design is specified but may be unsuitable. This could lead to departures from design being required

3 5 15 Standards have been used for other similar structures and has been specified by MKC Assumption included in proposal that standards will be suitable Jacobs to provide early warning should standard design found not be suitable

MKC 1 5

Data on utility company services is not available, or is incorrect leading to significant design changes.

4 5 20 Feasibility study has identified additional data required through gap analysis and provided opportunity for early engagement with Ringway for them to provide data via Trench

Ringway / MKC 4 5




Rev3 11/12/15

B0000000 FSP2

Surveys and GPR. Responsibility for accuracy and purpose of data supplied by others is not to be carried by Jacobs. Additional data for surface water drainage requested by MKC

Brief is not detailed enough. Deliverables do not meet client expectations

2 5 10 Early and regular engagement with both Ringway and MKC to confirm expectations. Better understanding through completion of Feasibility Study Design phase start-up meetings to be combined with site visits PM to undertake CES at project outset Jacobs to confirm understanding of requirements via proposal and raise queries in timely fashion Brief is to work to existing and documented standards. Jacobs team to undertake site visit to similar, already built structure to confirm understanding

Jacobs 1 5

GI factual & interpretative report delivery is currently scheduled outside programme milestones for preparation of design: impacts on programme.

5 3 15 Mitigate by commencing foundation design on assumptions in advance of GI report, subject to MKC carrying risk of any abortive design. Alternatively manage risk by accepting programme delay.

MKC 1 3

No archaeological watching brief during Ground Investigation works. Archaeological feature is found during works, leading to programme delays

2 4 8 Query raised at tender stage by Jacobs MKC stated that there was info contained within the Appendices to the briefs re. archaeology. Email in Appendices 02 states ‘No significant archaeology was found in the areas of investigation directly adjacent to the indicated locations and as such do not envisage any archaeological work as being required. Caveat included in proposal based on this assumption.

MKC 2 8

Results of additional surveys such as GI, topographical

2 5 10 Subway locations have been identified by client


1 5




Rev3 11/12/15

B0000000 FSP2

survey etc. are unfavourable, leading to design changes

Large amount of existing data gives confidence that locations are suitable Feasibility study has identified gaps in data. Ringway to arrange surveys in a timely fashion, such that survey data/results can be incorporated into the design Caveat included in proposal based on assumption that results are not unfavourable leading to significant re-design/abortive works.

Access not supplied for surveys. Design is required to proceed on the basis of assumptions, or delay to programme

2 4 10 Feasibility study has identified gaps in data and should provide adequate time for access to be arranged Feasibility Study has identified majority of scheme will be within MKC owned land so limited engagement required MKC to arrange access. MKC already engaging stake holders Caveat included in proposal based on this assumption


1 4

At J4 one proposed location of subway (phase 2 feasibility, option B) will require diversion of AW 900mm pipe unless redway ramp is steeper than standards (approximately 1 in 11 rather than standard of 1 in 20). This will lead to non-compliance with DDA standards

3 5 15 Issue identified during Feasibility Study phase 2 General Arrangement prepared at request of MKC to highlight issue MKC engaging with AW at early stage to mitigate programme delay and understand potential cost if diversion is required or level of protection AW required MKC to provide confirmation of departure from standard if option is progressed

MKC 2 10

At J4 Feasibility Study phase 2 options impact existing at grade Redway crossing of Miller’s Way. This will require diversion, non-standard ramp slopes or potentially an additional subway under Miller’s Way to maintain current crossing/Redway route

4 5 20 Issue identified during Feasibility Study phase 2 General Arrangement prepared at request of MKC to highlight issue MKC to consider when determining how project is to progress

MKC 2 10




Rev3 11/12/15

B0000000 FSP2

Gas Chamber and related pipe/ductwork installed on the south side of Watling Street adjacent to Junction 25 identified during site visit on 07/12/15 but not on supplied information. Potential clash with design option – lack of survey information.

3 4 12 Feasibility study phase 2 has identified additional surveys/investigations required for future design phases through gap analysis. MKC to undertake early engagement with service providers Regular stakeholder engagement, Jacobs & Ringway to provide input where required.


2 8

Existing culvert on the WEA development approach to Junction 25 discharging into ditches running parallel to the Watling Street identified during site visit on 07/12/15 but not on supplied information. May need diversion.

5 2 10 Feasibility study phase 2 has identified additional surveys/investigations required for future design phases through gap analysis. Confirmation of Culvert location, level and construction details required to determine if diversion/relocation is required in future design phase.


3 6

Attenuation Pond located in the south quadrant of the Junction 25 identified during site visit on 07/12/15 but not on supplied information, has potential to clash/impact with design.

5 2 10 Feasibility study phase 2 has identified additional surveys/investigations required for future design phases through gap analysis. MKC to provide Drainage information. Regular stakeholder engagement, Jacobs & Ringway to provide input where required. Relocation of Pond may be required.


3 6

Sub-station has been installed on the north side of Watling Street adjacent to Junction 4, identified during site visit on 07/12/15 but not on supplied information. Potential clash with design - No information available regarding sub-station and any related pipe/ductwork.

3 4 12 Feasibility study phase 2 has identified additional surveys/investigations required for future design phases through gap analysis. MKC to undertake early engagement with service providers Regular stakeholder engagement, Jacobs & Ringway to provide input where required.


3 6

Client Satisfaction

Failure to manage expectations of external stakeholders in terms of outputs of the study

3 3 9

Key stakeholders identified prior to project start up (Parks Trust, Milton Keynes Urban Design), and agreed with end client (MKC) Ongoing liaison with the external


1 3




Rev3 11/12/15

B0000000 FSP2

stakeholders via regular meetings and communications. MKC to determine when in project programme stakeholder engagement should take place. MKC already in contact with ley stakeholders

Change in scope/ programme / cost resulting in poor client perception of the deliverables

3 3 9

Regular client meetings, including key design discipline leads, Project Manager and stakeholders Regular update of risk register Regular progress reports to project team and client Regular progress meetings with project team PM to ensure early warning regarding any issues pertaining to scope, programme, cost or quality

Jacobs / Ringway 1 3

Programme

Data requested such as surveys, ground investigations data, is not supplied within timescales required for project, leading to assumptions in design or programme delays

3 5 15

Feasibility study has identified gaps in data Timely preparation of scope documents by Jacobs Ringway have supply chain for GI, utility survey and topographical survey works


Issues arising from public consultation require significant/time consuming design changes which affect the programme; Delays in responses from consultation lead to subsequent programme delay

2 4 8

Client has stated that public consultation is considered as information sharing exercise only There is public support for the scheme and it is widely recognised that the subways are required. Assumptions included in proposal and factored into programme regarding timeframe for responses Jacobs requested by MKC to provide attendance at key meetings/consultation to assist with presentation of scheme

MKC 1 4

Client/MKC fail to make timely decisions regarding project

2 4 8 Ringway / MK / LLFA to clarify decision makers and confirm in ToR


1 4




Rev3 11/12/15

B0000000 FSP2

issues, leading to project delays/abortive works

Regular client meetings, including key design discipline leads, Project Manager and stakeholders Jacobs to ensure timely provision of information to allow quality decision making

Resources

Resources currently available but programme not achieved in proposed timescales due to delay in commission from client, leading to clashes with other works

2 4 8 Resources have been identified and are currently available. If commission delayed PM to liaise regularly with team leader to ensure resources are still available. Inform client if delays likely and specify lead in time. Additional resources from Coventry could be made available


Resources shortage due to staff turnover and pressures of other projects

3 4 12 Dedicated team identified. PM to ensure early engagement and programming of the resources. MoP to ensure buy-in from other teams if needed for any acceleration of the programme.

Jacobs 1 4

Multi-disciplinary team fails to coherently cover all aspects of design

4 4 16 Each discipline responsibilities to be defined and reviewed by PM. Interactive planning session at prelim design phase start up to identify adjacencies and potential gaps Regular internal design team progress meetings – PM to coordinate

Jacobs 1 4

H&S

Site visits to meet client 4 5 20 Appropriate RAMS and TSPA’s to be used. PM to check on H&S training for team to cover site supervision, working at height, working over water, Chapt8-TM, asbestos awareness & on-line driver training as necessary. No lone working to be undertaken.

Jacobs 1 5




Rev3 11/12/15

B0000000 FSP2

Exposure to potential asbestos materials in trial holes

3 5 15 Mitigated by asbestos desk study being managed by Jacobs.

Jacobs 1 5

Health and Safety design issues no adequately captured

3 5 15 Designers Risk Assessment (Jacobs HERR forms) prepared at Feasibility Study phase and to be updated through project life cycle CDMC lead discipline appointed by PM at prelim design stage to ensure Designers Risk Assessment Forms (Jacobs HERR forms) comprehensively covered by all disciplines. CDM coordinator identified and to join project team from Prelim design phase Regular engagement with Ringway to ensure construction phase issues fully understood


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