YMS/1 Scarborough Bridge - York, North Yorkshire and … Scarborough Bridge Footbridge Renewal -...

YMS/1 Scarborough Bridge

Footbridge Renewal - Feasibility Report

LNE/148427/ECV/DOC/IAB/101

Rev – 02

Prepared for

CITY OF YORK COUNCIL

Scarborough Footbridge - Feasibility Study Network Rail Infrastructure Projects

30 September 2015

Author:

Name Arnab Chakraborty; CEng, MIStructE

Job Title Design Engineer

Signature

Date 10/11/2015

Checked by:

Name Mark Shaw; RIBA

Job Title Architect

Signature

Date 10/11/2015

Approved by:

Name Mark Shaw; RIBA

Job Title Architect

Signature

Date 10/11/2015

Accepted by:

Name Phil Daniel

Job Title Project Manager, IP LNE

Signature Date

Endorsed by:

Name Dan Guiher

Job Title Commercial Scheme Sponsor, LNE & EM Route

Signature Date

Version Comments

01 First issue for comment

02 With cost included, for submission to CYC.


30 September 2015

Glossary

NR - Network Rail

CYC - City of York Council

DfT - Department for Transport

DMRB - Design Manual for Roads and Bridges

TRL - Transport Research Laboratory

RRV - Road Rail Access Vehicle


30 September 2015

Contents

Executive Summary ....................................................................................................................... 1

Introduction .................................................................................................................................... 3

Scope ............................................................................................................................................... 4

Boundaries and Relationships ...................................................................................................... 5 Dependencies ......................................................................................................................... 5 Assumptions ........................................................................................................................... 6 Opportunities and Risks .......................................................................................................... 7

Design Methodology ...................................................................................................................... 8 Width ....................................................................................................................................... 8 Parapet Height ...................................................................................................................... 11

Option Criteria .............................................................................................................................. 12 Operational Alignment .......................................................................................................... 12 Specification Alignment ......................................................................................................... 13 Safe by Design ...................................................................................................................... 13 Environment and Sustainability ............................................................................................. 13

Option 1 ......................................................................................................................................... 15

Option 2 ......................................................................................................................................... 16 Technical Commentary (Option 2A & 2B) ............................................................................. 17 Programme ........................................................................................................................... 17 Constructability ..................................................................................................................... 17 Cost ....................................................................................................................................... 18

Option 3 ......................................................................................................................................... 20 Technical Commentary ......................................................................................................... 21 Programme ........................................................................................................................... 21 Constructability ..................................................................................................................... 21 Cost ....................................................................................................................................... 21

Options – Design basis for cost estimates ................................................................................ 23

Summary & Conclusion ............................................................................................................... 25

Further Work ................................................................................................................................. 26 Lessons Learnt ..................................................................................................................... 26


30 September 2015

GRIP 3 to 8 ........................................................................................................................... 26

References .................................................................................................................................... 27

Appendix I – Option Drawings ........................................................................................................

Appendix II – Archive Information ..................................................................................................

Appendix III – Design Decision Log ...............................................................................................

Appendix IV – Designer’s Risk Assessment .................................................................................


30 September 2015Page 1

Executive Summary City of York Council has commissioned Network Rail to carry out a feasibility study into the provision of a new cycle/footbridge across the river Ouse adjacent to the existing Scarborough railway bridge. The structure would replace the existing footbridge that is currently attached to the east side of the railway bridge.

The proposed upgrade will provide a wider bridge with improved access for over 500 cyclists who currently carry their bikes across the footbridge daily as well as pedestrians, pushchairs and wheelchair users. The proposals also include for improved and wider links between the riverside paths and the new bridge providing a more direct and convenient links between York station, the off road cycle network and the north side of the river.

The proposed bridge and its associated access paths are all to be restricted to a land area within the ownership of Network rail.

With reference to current standards for cycleways and accessible access, three proposals have been developed as part of this feasibility study. Two proposals involve extending the existing railway bridge structures and the third as a freestanding structure. All three options have been based around five core principles highlighted in the City of York Council remit.

Construction access

Work to existing bridge foundations

Minimum disruption to public and railway

Aesthetics and environment

Flood defence

Option 1 is based on a cable stayed bridge supported from an upgraded central pier. Due to cost and design risk issues this option was discounted at an early stage.

Option 2 is based on the simple structural concept of removing the existing footbridge and utilising its support position to accommodate a steel box beam off which the new cycle bridge deck can be cantilevered. Two deck widths have been included in the analysis.

Option 3 is a freestanding design featuring a single mastered suspension bridge with a 24 m high steel mast set on the north bank of the river

Options 2 and 3 have an expanded analysis which covers technical, programme, constructability and cost issues.

The feasibility concludes with a recommendation that favours option 2 due to its simplicity and cost, nevertheless the constructability of any bridge in such an inaccessible location will be problematic and will require further investigation during the next stage of design development.



Figure 1 Existing Footbridge; Stepped access (top), Limited width (bottom)



Introduction The original Railway Bridge over the River Ouse known as Stephenson’s Scarborough Railway Bridge was opened in 1845 and remained in use for almost thirty years. This bridge had a public footpath between two tracks reached by stairs inside each abutment. This bridge was renewed in 1875 using the original abutments and the centre pier although the footpath was retained, it was placed along the east side at its present position and the abutment stairways abandoned. The footbridge has steps both sides limiting access for wheelchairs and cyclists. Network Rail (NR) has completed the railway bridge deck renewal between 14 and 23 February and also owns the railway as well as the footbridge.

Plans to upgrade the footbridge have received the go ahead with secured funding for the City of York Council (CYC) through a West Yorkshire combined Authority bid to the Department for Transport (DfT) for a Cycle City Ambition Grant.

The upgrade will provide a wider bridge and improved access for over 500 cyclists who currently use the crossing daily as well as pedestrians, push chairs and for the first time the wheelchair users. The plans will also see improved and wider links between the riverside paths and the river crossing, providing a more direct connection to the York station from the off road cycle network.

Figure 2 Existing Footbridge with stepped access



Scope CYC has commissioned NR to progress the feasibility study for replacing the footbridge. The scope of work aims to establish a number of potential options including outline costs. This document covers the Phase 1 development of the options for a combined route for cyclists and pedestrians comprising access ramps, steps and bridge;

i. Undertaking necessary Topographical and Environmental surveys to enable valid options development,

ii. Prepare and assess footbridge and ramp layout options for future development in the following Phase,

iii. Providing outline costs for the options.

Figure 3 Illustrative Access Strategy with proposed upgrade of Footbridge



Boundaries and Relationships The Scarborough Bridge UB YMS/1 is owned and maintained by NR including the footbridge and the substructures. Any work to the bridge will also affect the CYC, Royal Mail, guest houses and business on the north bank of the river. TransPennine Express is the primary route operator running train services to and from Scarborough.

Figure 4 Existing Land Ownership

Dependencies

The proposal for the wider footbridge and the associated ramps are aimed to be restricted within the area of NR land ownership. The strip of land between east of the railway (ELR: YMS) and the boundary are considered adequate for the proposal. Apart from NR being the owner of the bridge and the lands on both sides of the River Ouse, the proposed options will also depend on the outcome of public consultations. Key input is expected from the CYC planners and Environment Agencies. A Diversity and Impact Assessment is proposed to be undertaken after the options selection and before starting the detailed design for the option.



Assumptions

This feasibility study and the options selection is developed with the following reasonable assumptions;

1. CYC will ensure necessary land for site access and compound areas be made available to the Contractor for construction works.

2. Any modifications, if required, to the existing flood defence will be acceptable to the Environment Agency.

3. Options to use existing railway bridge substructure will be validated during detailed design. Also if required any additional foundation options at the river bank abutments shall be acceptable to the Environment Agency.

4. Cast Iron piles below the Central Pier are considered acceptable, subject to validation during detailed design, with reasonable freshwater corrosion allowance.

5. Discussions for necessary planning consents shall be facilitated by CYC.

Constraints and Conflicts

Key external or internal constraints and conflicts which have influenced the designs or the options are listed below;

1. Existing Substructure (foundations) – existing substructures are not wide enough to accommodate the wider footbridge. If a wider footbridge option using existing substructure is preferred than stability of the widened walkway will impose additional constraint on the design.

2. Step access – it is possible to maintain existing stepped access to the upgraded footbridge while maintaining ramped access for Cycle and Wheel/Push chair users. Existing conflicts at the river banks need to be removed or improved.

3. Impact on flood defence – North ramp and unrestricted access to the riverside link will have an impact on the existing flood defence.

4. Cyclist access to the station – will encourage a short cut for cyclists using existing station car park and could become unsafe and crowded around the Taxi and parking bays at the side of the hotel Royal York.

5. Access to Post Office lane ramp – existing NR ramp access to car park from the Post Office lane offers challenge and will require integration with the overall scheme.

6. Public – Northern Riverbank is residential and the River Ouse is frequented by tourists and is popular for leisure activities. Any construction activities will impose significant constraints and will conflict with the local interests of businesses and residents.

7. Environmental – proposed upgrade will mitigate the impact upon existing trees and wildlife along the railway embankment.

8. The proposed ramp arrangement on the north bank will impact on the car parking that is currently provided at the side of the Abbey Guest House.



Opportunities and Risks

Opportunities;

1. Existing Substructure (foundations) – integrating existing substructures will provide huge cost saving to the scheme.

2. Stone Pilasters – Removing the eastern side stone pilaster from the central pier and the abutments will offer two benefits;

a. Pilaster on the abutments weighs minimum 10t. Permanent removal of these pilasters will offer dead weight relief to accommodate 3.5m deck with additional live loads. Next phase of detailed should look for exploring this opportunity.

b. Removal of the pilaster will make way for sitting wider bridge beam.

3. Existing Flood defence – positioning north side access and ramps inside the flood defence wall will avoid expensive modification to the existing flood defence system and also the design will offer pedestrian access from the Marygate car park to York Railway Station even during the flood when the river gates are closed.

Risks;

1. Existing Substructure (foundations) – Both the abutments and the central pier need detailed assessment prior to detailed design. Also refer to the design decision log.

2. Built Cost – Option 2 assumes that the existing substructures are adequate for the wider footbridge. If otherwise this will add significant cost and program to the estimates.

3. Planning approval – The options considered in this report has been developed without any discussions or input from the stakeholders and the planners. It is envisaged that the next stage of design delivery will commence after the discussions with the stakeholders and the planning authorities.



Design Methodology

Width

In order to satisfy the five core principles of the CYC remit, the footbridge width is considered to be one of the most important criteria for this feasibility study. CYC has requested the impact and cost for various footbridge widths;

Absolute minimum: 3m

Desirable: 4m

Aspiration: 5m

Following guidelines have been referred to identify the recommended and minimum widths by various Authorities;

DMRB; Volume 2 Section 2 Part 8 BD 29/04

Table 1: Section 12.4 – the minimum widths for a footpath (or footway) and a cycle track on a bridge and ramps shall be;

Pedestrian Path Cycle Path Total Width

When segregated by a white line, colour contrast or surface texture

1.5m 1.5m 3.0m

Unsegregated - - 2.0m

Table 2: DfT; LTN 2/04 – Adjacent and Shared use Facilities for Pedestrians and Cyclists


Recommended Width 2.0m 3.0m 5.0m

Minimum Width 1.5m 2.0m 3.5m

Table 3: TRL; Application guide AG26 (Version 2)


Recommended Width 2.0m 2.0m 4.0m

Minimum 2.0m 1.5m 3.5m



The Handbook for Cycle-Friendly Design by SUSTRANS offers some useful dimensions



Considering above recommendations and suggested dimensions the following widths have been adopted for this feasibility study;

Table 4

Segregated by a white line, colour contrast or surface texture


Aspiration

1.5m 3.0m 4.5m

Minimum 1.5m 2.0m 3.5m



Parapet Height

The CYC remit for the riverside parapet height is 1.4m in accordance with current guidance. Following codes and standards have been reviewed to confirm the latest requirements;

BS EN 1317-6 : under preparation

BS 7818:1995

Class 3: Normal requirement, Heavy Duty

1.4m high

1.4kN/m horizontal load (similar to earlier P4)

DMRB; Volume 2 Section 2 Part 8 BD 29/04

Section 12.5 – On footbridges with cycle facilities the minimum height of a parapet shall be 1.40m.

Section 6.8 – Consideration should be given by the designer to the provision of solid infill panels to parapets and step risers to protect the privacy of users and screening to protect the privacy of the neighbouring dwellings.

NR/L3/CIV/020

Although this footbridge is independent of railway requirements, the railway side parapet is proposed to be 1.8m high. The railway side parapet will be non-perforate over its full length and is without hand or footholds.

Additionally the railway side parapet will sympathetically match the ornate features of the existing to ensure that all aesthetic appeals are satisfied.

Considering above recommendations and suggested dimensions the following parapet heights have been adopted for this feasibility study;

Table 5

Total Width

Riverside parapet 1.4m

Railway side parapet (Without hand or footholds and with 25x25 square mesh) sympathetic to existing ornate feature.

1.8m



Option Criteria All options are developed around five core principles mentioned in CYC remit. Key elements defining the options development are;

Construction Access – The footbridge spans River Ouse and land locked with no direct site access by any major road. Existing Marygate Car Park located at the north offers the opportunity to set up the site compound. Road Rail access is possible from the renewed rail bridge, however the lifting capacities using the RRV due to perpendicular lifting operations are limited.

Work on existing bridge foundations

o Central Pier – the record information offers sufficient information to estimate the cast iron pile capacity and corresponding safe load carrying capacity of the central pier. However the pile capacities need to be validated as part of the detailed design exercise. Existing stone pilaster at the central pier weigh approximately 5t.

o Abutments – existing abutments are founded on 11x7 rows of Timber piles. But there are no design details available to accurately assess these piles. Therefore any changes to the overall loading will require careful comparison with existing and new loadings. Existing eastern pilasters on the abutments weigh approximately 10t.

o Removal of these pilasters from eastern side elevations of the existing footbridge will provide space for sitting new and wider footbridge beam and additionally the reduction in dead weight will help to accommodate heavier footbridge. Therefore the effect of additional loads particularly on the abutments will reduce significantly and may avoid the need for any further work in strengthening or widening the abutment foundations.

Minimum disruption to the public and railway – proposed upgrade for the footbridge and options will be aimed at minimum disruptions to the neighbours, tourists and the railway.

Aesthetics and Environment – the Scarborough Rail Bridge has historical significance and stands out when viewed from the Lendal Bridge and while approaching towards York City Centre. All options will be developed sympathetically considering the history and background of the existing bridge.

Flood Defence – The existing flood gate arrangement along the northern bank to the side of the Abbey Guest House will be compromised by the proposed ramp arrangement. New proposals for the reinstatement of the flood gate will be prepared in consultation with the Environment agency and the local planners.

Operational Alignment

All options will provide 24x7 access for the bridge crossing and ramps. The Southern end of the ramp will divert offering the pedestrian and cyclists the choice to either continue to the station or follow the Post Office lane. Existing NR gate at the Post Office lane will require relocation to enable this operation.



Appropriate LED lighting will be mounted on the balustrades avoiding any interferences or obstructions to the railway signalling. CCTV installation and location will be agreed during the next phase of the design.

Specification Alignment

Proposed route including the ramps on the northern and southern river banks will be kept within the NR boundary or the CYC owned land. DDA compliant ramps satisfying guidelines for safety of the cyclists and pushchair/wheelchair users will be provided. Ramps will be designed to reduce the conflicts between the pedestrian and the cyclists and offer good visibility and lighting for security.

Safe by Design

Although the footbridge/cycleway can be set against the railway parapet on the bridge itself, (Option 2) beyond the bridge (at both ends) the new footpath/cycleway will need to be set away from the railway to avoid the need to both remove the existing pilasters (at the extreme ends of the railway bridge) and avoid the need for disruptive retaining works on the edge of the railway alignment. This also allows the retention of the existing staircase positions at both ends of the bridge.

All proposed options will look to minimise or completely avoid works or elements of work that will pose significant risks during construction, maintenance and operations.

1. River Ouse is tidal and known for its flooding every year, therefore installations of temporary works and working over the river needs to be minimised.

2. Approach embankments are of limited stability; this is based on the experience of the Railway Bridge construction. Design and Construction of the ramps for the proposed cycleway will provide retaining walls to stabilise the approach embankments.

3. A 1.8m non-perforate parapet is chosen along the railway side not only to replicate the existing ornate feature but also to prevent any public intrusion within the railway.

4. Stepped access and the cycle path at the ends of the bridge will be clearly separated by physical barriers beside providing lighting, signage and tactile.

5. Ramps will be designed with clear visibility and safe turning radius for the cyclists.

Environment and Sustainability

Provision of the wider and continuous cycle and pedestrian route across the River Ouse will facilitate active travel modes by more sustainable way. The proposed footbridge upgrade will benefit the National Route 65 of the National Cycle Network runs from Hornsea to Middlesbrough and also forms a part of the Trans Pennine Trail (east) cycle route between Selby and Hornsea.

Proposed ramps to North through Marygate Car Park will offer resilience by design maintaining continued access to York station even during high river levels when flood gates are deployed.

An Ecology Survey and risk assessment was undertaken in July 2014 prior to the Railway Bridge renewal now completed in February 2015. The survey had identified the ecological constraints and



their corresponding risk levels for carrying out major bridge construction works. The proposed footbridge upgrade work will have similar consequences in term of the construction, mobilisation and maintenance. Similarly Nesting Birds, Bats, Badgers and River Ouse will be potentially affected as was identified in the ecological report. The risk levels in this report was minor and reasonable therefore possible to mitigate by strategic implementation and monitoring. Based on the evidences from the Railway Bridge construction it is reasonable to consider that all the ecological impacts are manageable. However a further ecological survey is recommended. Schedule the survey at least two years before the site works. This is to be noted that the construction and delivery programme is unknown while writing this report.



Option 1 A Cable stayed bridge supported from the existing central pier will relive any additional works to the river bank abutments. The central pier will require widening or extending to support the proposed mast. This option will require major foundation works to the central pier. Additional piling close to existing cast iron piles may disturb the ground condition and could have unknown effect on the stability of the existing pier. Apart from attributing a severe risk to the design and installation, the cost of construction and mobilisation would appear to be significant for this option. During the initial review period and workshop with CYC it was agreed to discount this option.

Figure 4 Option 1 – Footbridge Cable stayed from Central Pier



Option 2 This is based on the simple structural concept of removing the existing footbridge and utilising its support position to accommodate a steel box beam off which the new wider deck will be cantilevered.

The box beam is tied back to the rail bridge on the west side while the east side towards Lendal Bridge features a set of substantial steel balustrades that are both functional and decorative.

Designed to resemble the monolithic castings prevalent in York’s Victorian river crossings, the form of the struts loosely relates to forms found in Viking art or perhaps the struts of a long timber hull.

The form of the bridge is designed to provide visual interest when viewed from all angles including underneath from passing boats while the uncluttered functionality of the steel cable balustrade and clear wide cycleway provides a solution that is both modern and traditional, yet maintains a respect for the existing structure on which it relies.

Existing stepped access will be improved and retained. The cycleway to the east of the bridge will continue beyond the riverbanks via ramps and connected to the Marygate Car Park in the north and the York Station Car Park in the south.

Figure 4 Option 2 – Functional, modern and traditional



Technical Commentary (Option 2A & 2B)

Existing footbridge offers 1.3m clear footway for pedestrians. Option 2A is developed with a maximum 4.5m wide combined pedestrian and cycleway. Removal of the existing footbridge and the eastern pilaster will provide 2.5m clear sitting for the new bridge beams at the abutments and the central pier. The rotational instability of the wider bridge will be compensated by tying with the existing rail bridge. A similar arrangement is already in place for the existing footbridge. Depending on the sequence of construction the bridge will be installed with consideration to the stability of the whole system during the construction and operation.

Figure 4 Option 2 – Structural Concept

Option 2B is developed considering a minimum 3.5m wide combined pedestrian and cycleway.

Programme Based on initial enquiries with the competent contractors the construct only duration for the complete upgrade of the footbridge will be 20 weeks. The overall programme for delivering a design and build service from the commission to completion will be a minimum of 56 weeks. This will include 24 weeks of design and a minimum 12 weeks of procurement/fabrication of steelworks.

Constructability

Two completely independent methods of construction are suitable for this option;

LIFT 1LIFT 2 LIFT 3

- Existing Rail Bridge

providing rotational stability

of the cantilevered deck



Using Large Crane – mobilising a single large crane from the north of the River to install the footbridge steelwork is possible. A similar construction technique was used for the Rail Bridge installation in February 2015.

Launching – The footbridge can be launched from the northern side avoiding the need for remobilising the large crane. Similar construction methods were successfully implemented for a number of NR projects, e.g., East Croydon footbridge.

Cost

A single source cost for this option is obtained from a competent contractor. Following elements were considered while developing the cost;

Inclusion;

- Installation using mobile cranes

- 5% risk allowance for the design developments

Exclusion;

- Land Access cost

- River Closure cost

- Services diversion

- Local authority cost

- Christmas working



Table 6 – Option 2A; Budget Cost

(Refer to Table – 9 for design considerations in the background of the cost estimate)

Items of Work Cost Remarks

Option 2A

4.5m wide steel footbridge;80t steel 240m x 4m Ramps including earthworks Design & Build

£3,640,000

NR costs

PM Services, route support, industry consents, sponsorship, asset management, possessions, legal, property, & planning

£764,400

Network Rail Fee Fund & Industry Risk Fee (based on emerging cost funding agreement)

£308,308

Contingency £660,660

CYC costs - CYC to add, if necessary

Gross Budget Cost £5,373,368 Option 2A - 4.5m wide Bridge

Table 7 – Option 2B; Budget Cost



Option 2B

3.5m wide steel footbridge;70t 190m x 3m Ramps including earthworks Design & Build

£3,472,000

NR costs


£729,120


£294,078



Gross Budget Cost £5,125,366 Option 2B - 3.5m wide Bridge



Option 3 Unlike the previous option, Option 3 is a freestanding structure which sits about two metres to the east of the existing footbridge (which is also to be retained).

The design features a single mastered suspension bridge with a 24 meter high steel mast set on the north side of the river adjacent to the existing bridge abutment. A lightweight structure reaches across the river forming a gentle arch to meet a new abutment on the south bank.

Beyond the mast on the north side the cable supports run back to an anchor point that is placed adjacent to the ramp. The ramp is to be detailed to complement the light structure of the suspension bridge itself allowing the two elements to read visually as one.

Existing stepped access will be improved and retained. The cycleway to the east of the bridge will continue beyond the riverbanks via ramps and connected to the Marygate Car Park in the north and the York Station Car Park in the south.

Figure 5 Option 3 – Standalone Iconic Cable Stayed Bridge



Technical Commentary

Existing footbridge offers 1.3m clear footway for pedestrian. Option 3 is developed with a maximum 3.5m wide combined pedestrian and cycleway. An independent cable stayed bridge is proposed to be located at least 2m east of the existing footbridge. A major piled foundation will be required for the mast located at the north of the River. Cables are tied back where the existing redundant pile cap is now remaining. There is an opportunity to assess and reuse this pile cap for tie-back.

Programme

Based on the initial enquiries with the competent contractors the construct only duration for the complete upgrade of the footbridge will be 24 weeks. Over programme for delivering a design and built service from the commission to completion will be a minimum of 72 weeks. This will include 36 weeks of design and a minimum 12 weeks of procurement/fabrication of steelworks.

Constructability

Two completely independent methods of construction are suitable for this option;

Using Large Crane – mobilising a single large crane from the north of the River to install the footbridge steelwork is possible. A similar construction technique was used for the Rail Bridge installation in February 2015.

Combination of RRV and Mobile Cranes – it is also possible to construct the river spans using RRV. Individual segments of the bridge can be installed and tied back before proceeding to lift next segments. A mobile crane to install the cable stay mast at the North span will be necessary, but of lesser lifting capacity.

Cost

A single source cost for this option is obtained from a competent contractor. Following elements were considered while developing the cost;

Inclusion;

- Installation using mobile cranes

- 5% risk allowance for the design developments

Exclusion;

- Land Access cost

- River Closure cost

- Services diversion

- Local authority cost

- Christmas working



Table 8 – Option 3; Budget Cost



Option 3

4.5m wide Cable Stayed 240m x 4m Ramps including earthworks Design & Build

£5,208,000

NR costs


£1,093,680


£441,118



Gross Budget Cost £7,688,050 Option 3 - 3.5m wide Cable Stayed



Options – Design basis for cost estimates Built costs in the preceding options are based on the following design considerations.

Table 9 – A summary of the background design details that formed the basis of the built-cost

Option 2A 2B 3

Description 1.2w x 1m deep 1.2w x 1m deep Cable Stayed Steel Box Beam Steel Box Beam 3.5m wide 4.5m wide deck 3.5m wide deck

Footbridge

River Span No 2 2 1 Width 4.5m 3.5m 3.5m Length 24m 24m 60m Weights 45t 35t Gross weight 90t 70t 60t

Side Span No 2 2 N/A Width 3m 3m Length 10m 10m Weights 12t 12t Gross weight 24t 24t

Foundation Single column on Not Applicable Piled foundation at northern River Bank For the Mast

pile at the river bank beside the

abutment Cable Stay tie backs

Foundation at Railway embankment

Where present Crane pad foundation is present



Table 9 - continued

Option 2A 2B 3

Ramp

North (Marygate) No 3 3 3 Length 35m 35m 35m Total Length 105m 105m 105m Width 3m 3m 3m Retaining 175m Long; 175m Long; 175m Long; Wall 1m - 3.5m high 1m - 3.5m high 1m - 3.5m high

South (York) No 2 2 2 Length 40m 40m 40m Total Length 80m 80m 80m Wide 3m 3m 3m Retaining 80m Long; 80m Long; 80m Long; Wall 1m - 3.5m high 1m - 3.5m high 1m - 3.5m high



Summary & Conclusion The early omission of Option 1 highlighted the need to respect the limitations of the existing 150 year old bridge. Although the construction of the abutments and central pier are well documented, the current condition of these elements cannot be fully ascertained.

The risks involved in adding further load to these structures has influenced the development of Options 2 and 3.

Option 3, as a freestanding structure completely negates the risk involved with the existing bridge, but at a cost.

Option 2 continues to rely on the existing structures but cleverly reduces the risk of overloading by removing the existing footbridge lattice girders and the large stone pilasters, the weight of the new footbridge can be substantially offset.

Both options 2 and 3 offer similar challenges in respect of constructability but technically Option 2 is a much simpler solution than the suspension bridge of Option 3.

Aesthetically the two options offer a completely different approach. The structural simplicity of Option 2 relies on the visual impact of the combined, cantilevered struts/balusters to define the style and identity of the bridge. The repetition of the heavy sculpted balusters linked by a stainless steel tension cabled balustrade, stretching across the river provides a traditional solution with clean lines of modern contemporary.

The aesthetics of Option 3 relate directly to the structural solution. The substantial 24m steel mast set on the north bank supports an elegant, gently arched, slim deck that free-spans across the river. The light structure contrasts with the heavy engineering of the adjacent railway bridge yet, surprisingly does not seem to visually clash with it. Nevertheless, an iconic structure of this type would benefit from a less cluttered location. The position of the mast, close to the homes on the north bank may well cause some issues with the local residents. The removal of the existing step access footbridge remains optional.

The linking path/ramp arrangements at the ends of the bridge are the same for both options and the estimated cost for these earthworks of £1.090 million remain constant for both options.

Two costings have been provided for Option 2 based on the width of the deck. The wider 4.5m deck option at £1,510,000 is only £120,000 more expensive than the narrower 3.5m option at £1,390,000.

The single Option 3 figure at £2,630,000 is more than £1 million more expensive than the wide deck version of Option 2.

At this feasibility stage, the Option2 wide deck would appear to offer the best balance between compromise and value for money at a gross budget figure of £2.6 million for the bridge and associated paths/ramps. Further design development, especially in the area of constructability will help to make future budget costings more robust.



Further Work

Lessons Learnt

Bridge Abutments – There isn’t enough record information available to assess the bridge abutments for additional loadings. The next phase of the design should consider the benefits of removal of the stone plasters and restricting the overall load increase to match the existing.

GRIP 3 to 8

Next stage of the design phase should consider a robust single option development considering the following;

1. Engage stakeholders and planners,

2. Undertake preliminary consultations,

3. Involve Contractors early to develop a cost effective and constructible design that will not only offer economy but also will have limited effect on the neighbourhood and the businesses.



References Network Rail Standards

NR/CS/CIV/044 (1) Managing Structures Works

NR/GN/CIV/001 (3) Waterproofing of Underline Bridge Decks

NR/GN/CIV/002 (5) The use of protective coatings and sealants

NR/GN/CIV/133 (1) Information required for an Approval in Principle submission

NR/GN/CIV/801 (3) The application of the Observational Approach to the design of remedial

works to Earthworks

NR/GN/ENV/00023 (2) Control of Noise and Vibrations from Construction Operations

NR/L1/INI/CP1010 - 1 Policy on working safely in the vicinity of buried services

NR/L1/TRK/05200 (2) Vegetation

NR/L2/AIF/1020 (1) Buried services data provision

NR/L2/AIF/1040 (1) Buried services data feedback

NR/L2/CIV/003 (4) Engineering Assurance of Building and Civil Engineering Works

NR/GN/CIV/025 The structural assessment of underbridges

NR/L2/CIV/003/F1990 Technical Design Requirements for BS EN 1990: Eurocode – Basis of

Structural Design

NR/L2/CIV/003/F1991 Technical Design Requirements for BS EN 1991: Eurocode 1: Actions on

Structures

NR/L2/CIV/003/F1992 Technical Design Requirements for BS EN 1992: Eurocode 2: Design of

Concrete Structures

NR/L2/CIV/003/F1993 Technical Design Requirements for BS EN 1993: Eurocode 3: Design of

Steel Structures

NR/L2/CIV/003/F1997 Technical Design Requirements for BS EN 1997: Eurocode 7:

Geotechnical Design

NR/L2/CIV/086 (3) Management of Earthworks

NR/L2/INI/02009 (5) Engineering Management for Projects

NR/L2/INI/CP0047 (4)

Application of the Construction Design and Management Regulations to

Network Rail construction projects

NR/L2/INI/CP1030 (1) Working safely in the vicinity of buried services

NR/L2/TRK/2049 (12) Track Designers Handbook

NR/L2/TRK/2102 (6) Design and Construction of Track



NR/L2/TRK/3038 (5) Longitudinal timbers – Design, installation and maintenance

NR/L2/TRK/2500 (3) Engineering Assurance Arrangements for Track Engineering Projects

NR/L3/CIV/005 (2) Railways Drainage Systems Manual

NR/L3/CIV/020 (1) Design of Bridges

NR/L3/CIV/039 (5) Specification for the Assessment and Certification of Protective Coatings

and Sealants

NR/L3/CIV/040 (1) Specification for the use of Protective Coating Systems

NR/L3/CIV/041 (3) Waterproofing Systems for Underline Bridge Decks

NR/L3/CIV/071 (4) Geotechnical Design

NR/L3/CIV/140 (10) Model Clauses for Civil Engineering works

NR/L3/CIV/151 (6) Engineering Assurance of Standard Designs and Details for Building and

Civil Engineering Works

NR/SP/BUS/011 (5) Prevention of Damage to and Danger from Surface & Buried Services

NR/SP/OHS/021 (3) Personal protective equipment and work wear (PPE)

NR/SP/OHS/069 (2) Lineside Facilities for Personnel Safety

RT/CE/S/010 (2) Geotextiles

Railway Group Standards

GC/RT5112 (2) Rail Traffic Loading Requirements for the Design of Railway Structures

GC/RT5212 (1) Requirements for Defining and Maintaining Clearances

GE/GN8573 (3) Guidance on Gauging

GE/RT8073 (2) Requirements for the Application of Standard Vehicle Gauges

Construction Design and Management Regulations 2007

HMRI Principles and Guidance Documents

Part 1 - Railway safety principles and guidance Part 1 (1996)

Part 2 - Section A Guidance on the infrastructure (1996)

Eurocodes (to be read with associated National Annex and any referenced Published

Documents and other NCCI)



BS EN 1990 Eurocode 0: Basis of structural design

BS EN 1991-1-1 Eurocode 1: Actions on structures – General actions – Densities, self-

weight and imposed loads

BS EN 1991-1-4 Eurocode 1: Actions on structures – General actions – Wind actions

BS EN 1991-1-6 Eurocode 1: Actions on structures – General actions – Actions during

execution

BS EN 1991-1-7 Eurocode 1: Actions on structures – General actions – Accidental actions

BS EN 1991 Part 2 Eurocode 1: Actions on structures – Traffic loads on bridges

BS EN 1991-3 Eurocode 1: Actions on structures – Actions induced by cranes and

machinery

BS EN 1992-1-1 Eurocode 2: Design of concrete structures – General – Common rules

for building and civil engineering structures

BS EN 1992 Part 2 Eurocode 2: Design of concrete structures – Bridges

BS EN 1993-1-1 Eurocode 3: Design of steel structures – General rules and rules for

buildings

BS EN 1993-1-9 Eurocode 3: Design of Steel Structures – Fatigue

BS EN 1993-2 Eurocode 3: Design of steel structures – Steel Bridges

BS EN 1997-1 Eurocode 7: Geotechnical design – General rules

BS EN 1997-2 Eurocode 7: Geotechnical design – Ground investigation & testing.

PD 6694-1 Recommendations for the design of structures subject to traffic loading to

BS EN 1997-1:2004

British Standards

BS 8002 Code of practice for earth retaining structures

BS 8666:2005 Scheduling, dimensioning, bending and cutting of steel reinforcement for

concrete. Specification

BS EN 206-1 (2002) Concrete Part 1: Specification, Performance, Production and Conformity.

BS 8500-1 (2006) Concrete. Complementary British Standard to BS EN 206-1. Method of

specifying and guidance for the specifier.

BS 8500-2 (2006) Concrete. Complementary British Standard to BS EN 206-1.

Specification for constituent materials and concrete.

BS EN 10025 Hot rolled products of structural steels

BS5628-1 2005 Code of practice for the use of Masonry, Structural use of unreinforced

Masonry



BS5628-3 2005 Code of practice for the use of Masonry, Materials and Components,

design and Workmanship

Others

BD37/01 Loads for Highway Bridges

BD21/01 Assessment of Highway Bridges and Structures

BD16/97 Assessment of Highway Bridges and Structures

BD29/04 Design Criteria for Footbridges

DfT; LTN 2/04 Adjacent and Shared use Facilities for Pedestrians and Cyclists

TRL; Application Guide

AG26 (version 2)

Footway and Cycle Route Design, Construction and Maintenance Guide

SUSTRANS Handbook for Cycle Friendly Design



Appendix I – Option Drawings



Appendix II – Archive Information



Appendix III – Design Decision Log

Building & Civils Design Group

Quality Form

Design Decision Log

Ref No:

Issue:

Date:

Page:

QMS-T405

1.0

27-08-15

1 of 1

Job Ref: Project Rev Prepared By Date: Checked By: Date: Approved By: Date:

148427 Scarborough Footbridge Feasibility 01 AC 26/10/2015 MS 27/10/2015 MS 27/10/2015

Ref By Date Design Decision Decision Effect

(Impact on cost, programme, risks etc) Designer’s

Risk Ref

DD01 AC Removal of stone pilasters.

Stone pilasters pose a definite risk for the users. Additionally removal of pilasters weighing 10t at the abutments and 5t at the central piers will compensate for increased dead weight and live load from wider footbridge.

DR01

DD02 AC Existing stepped access.

Stepped access will be maintained and provided from the same location. Mainly because this will help in keeping the cyclists and the ramps away from the railway boundary. Keeping cycleway nearer to the railway will bring the ramps closer to the railway track. This is considered to be difficult in managing the ramp alignment and construction at the bridge abutments.

DR02

DD03 AC Flood defence. Proposed ramp at the Marygate car park is not envisaged to alter the existing flood defence. Therefore this is not included in the built cost.

DR03

DD04 AC Use of existing bridge substructures.

Abutments – Historically abutments are founded on 7 rows of 11 timber piles. There is not enough information available to accurately access the foundation capacities. A 3.5m wide footbridge has a definite advantage over 4.5m wide footbridge that when the existing pilasters are removed, it is possible to restrict the overall vertical load and the corresponding bearing pressure to nearly match corresponding existing values. Piers – cast iron piles with assumed corrosion values are assessed to be adequate in carrying the wider footbridge. However this assumption needs to be validated or agreed upon prior to the detailed design.

DR04

DD05 AC Planning approval.

Proposed footbridge forms and elevations are assumed to be acceptable to the Planners and the approving Authorities. This feasibility report is prepared without any consulations with the relevant stakeholders and planners.



Appendix IV – Designer’s Risk Assessment

Design Risk Assessment

YMS/1 Scarborough Bridge; Footbridge Renewal ELR YMS; 0mls 0396yds

26 November 2015

OP Reference: 148427 Project Manager: Phil Daniel Sponsor: Dan Guiher

QMS-T404 Issue 1.0 27/08/15

Network Rail Infrastructure Projects - Strictly Private and Confidential

27/10/2015

Buildings and Civil Design Group

York ICC, Leeman Road, York, YO26 4XD

Revision History

Version Date Details Prepared by Reviewed by Approved by

01 26/10/15 Feasibility Design stage assessment

Arnab Chakraborty Design Engineer

Mark Shaw Architect

Mark Shaw Architect


27/10/2015

Contents

1. DESIGN RISK ASSESSMENT 1

2. PROJECT OVERVIEW / SCOPE OF WORKS 3


19/06/2015

1

1. Design Risk Assessment

This Design Risk Assessment has been compiled at the early feasibility stage for the proposed Footbridge renewal at YMS/1 Scarborough Bridge

Roles and Responsibilities

The Client duties listed below are only a summary of the duties listed in CDM 2015 regulations. Each duty holder should make themselves fully aware of their responsibilities under these regulations. For further detail on the roles and responsibilities under CDM 2015, refer to the Guidance on Regulations (Approved Code of Practice) published by the Health and Safety Executive (HSE).

NB: The Construction Design and Management Regulations 2015 (CDM 2015) came into force on 6 April 2015, replacing CDM 2007. CDM 2015 is subject to certain transitional provisions which apply to construction projects that start before the Regulations come into force and continue beyond that date.


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2

Client’s Duties

The Clients duties for managing projects in accordance with the CDM regulations 2015 are as follows (Construction Design and Management Regulations 2015 – Guidance on Regulations. HSE):

The Client must

1. make suitable arrangements for managing a project, including the allocation of sufficient time and other resources.

2. ensure arrangements are suitable ensuring that

the construction work can be carried out, so far as is reasonably practicable, without risks to the health or safety of any person affected by the project; and

the facilities required by Schedule 2 are provided in respect of any person carrying out construction work.

3. ensure that these arrangements are maintained and reviewed throughout the project.

4. provide pre-construction information as soon as is practicable to every Designer and Contractor appointed, or being considered for appointment, to the project.

5. ensure that (a) before the construction phase begins, a construction phase plan is drawn up by the Contractor if there is only one Contractor, or by the Principal Contractor; and (b) the Principal Designer prepares a health and safety file for the project, which

complies with the requirements of regulation 12(5);

is revised from time to time as appropriate to incorporate any relevant new information; and

is kept available for inspection by any person who may need it to comply with the relevant legal requirements.

6. take reasonable steps to ensure that

the Principal Designer complies with any other Principal Designer duties in regulations 11 and 12; and

the Principal Contractor complies with any other Principal Contractor duties in regulations 12 to 14;

7. If a Client disposes of the Client’s interest in the structure, the Client complies with the duty in paragraph (5)(b)(iii) by providing the health and safety file to the person who acquires the Client’s interest in the structure and ensuring that the person is aware of the nature and purpose of the file.


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3

Designer’s Duties

The Designers duties for managing projects in accordance with the CDM regulations 2015 are as follows (Construction Design and Management Regulations 2015 – Guidance on Regulations. HSE):

Designers must 1) understand and be aware of significant risks that construction workers can be exposed to,

and how these can arise from design decisions 2) have the right skills, knowledge, and experience, and be adequately resourced to address

the health and safety issues likely to be involved in the design 3) check that Clients are aware of their duties co-operate with others who have

responsibilities, in particular the Principal Designer 4) take into account the general principles of prevention when carrying out design work

(which are set out in Annex D) 5) provide information about the risks arising from their design 6) co-ordinate their work with that of others in order to improve the way in which risks are

managed and controlled.

Contractor’s Duties

The Contractor’s duties for managing projects in accordance with the CDM regulations 2015 are as follows (Construction Design and Management Regulations 2015 – Guidance on Regulations. HSE):

1. ensure those carrying out your work have the right skills, knowledge, training, experience and supervision

2. ensure those carrying out your work have the right plant, tools, equipment, materials and personal protective equipment

3. pass on relevant information and instructions to workers. This could be done by briefing workers and, for higher risk tasks, using a safety method statement which outlines the planned method, sequence and control measures

4. ensure that your workers comply with the site rules

5. if required, co-ordinate your work with those of other Contractors and the Principal Contractor

6. agree with the Principal Contractor the arrangements for exchanging information to allow you both and other Contractors to manage health and safety

7. ensure your workers receive a site induction

8. allow workers sufficient time to prepare and carry out the work

9. inform the Principal Contractor of any intention to sub-contract elements of your work.


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4

Principal Designer’s Duties

The Principal Designer’s duties for managing projects in accordance with the CDM regulations 2015 are as follows (Construction Design and Management Regulations 2015 – Guidance on Regulations. HSE):

The Principal Designer must:

1. assist the Client in identifying, obtaining and collating the pre-construction information

2. provide pre-construction information to Designers, Principal Contractor and Contractors

3. ensure that Designers comply with their duties and co-operate with each other

4. liaise with the Principal Contractor for the duration of your appointment

5. prepare the health and safety file.


19/06/2015

5

2. Project Overview / Scope of Works

OP No. 148427 Design Risk Assessment -

Description of Project: Existing footbridge to the east of YMS/1 Scarborough Bridge has received a go ahead for upgrade to a wider footbridge with combined pedestrian and cycleway. The proposed bridge will also offer additional ramp access to and from Marygate Car park at north and York Station Car Park at south of the river Ouse. Design Principles: The proposed wider footbridge will be designed in accordance with the following Eurocodes and their respective UK National Annex (NA): BS EN 1990 Eurocode 0: Basis of Structural Design BS EN 1991 Eurocode 1: Actions on Structures BS EN 1991 Eurocode 2: Design of Concrete Structures BS EN 1991 Eurocode 3: Design of Steel Structures BS EN 1991 Eurocode 7: Geotechnical Design Work Activities:

The work required as part of this design includes, but is not limited to, the following: Land is under Network Rail/CYC ownership and all access is via local roads. Establish a site compound, temporary fencing and access arrangements at

Marygate Car Park. The clearance of vegetation and debris including approximately 80m from the river

banks Install scaffolding and temporary footbridge for access Set-up site/RRV cranes Prepare approach ramps and retaining walls along the railway embankments Removal of existing footbridge. Remove pilesaters Prepare abutments and the central pier bearing selves. Undertake substructure works, if necessary Install Precast concrete cill units Install new footbridge as per approved construction methodology Complete approach ramps Install lighting/CCTV. Remove all temporary works and scaffoldings.


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6

Make good the site.

Operation: The proposed works will renew existing narrower footbridge with a wider combined cycleway and pedestrian footbridge. Inspection and Maintenance: Proposed structure will be fabricated from weathering steel to avoid any maintenance from underside of the bridge needing river closure. Decommissioning / Demolition The works do not introduce any unusual features that will impact any future demolition works. Note: This Design Risk Assessment is not a comprehensive assessment of all risks associated with the project and its location. This Design Risk Assessment highlights all the risks that a competent Contractor may not assume to exist upon a worksite.

Likelihood Severity (Health & Safety) Severity (Environmental)

1 = Very unlikely 1 = Minor injury 1 = Minor environmental incident with no legislative breach 2 = Unlikely 2 = Lost time injury 2 = Potential for complaints from local residents, no legislative breach 3 = Likely 3 = Reportable injury/dangerous occurrence 3 = Potential for lost time/complaints from Local Authority for legislative breach 4 = Very likely 4 = Major injury 4 = Minor legislative breach with potential for prosecution 5 = Certain 5 = Fatality 5 = Potential for major environmental incident with high clean up and/or prosecution costs Risk Rating 1 – 3 = Low 4 – 6 = Medium/Tolerable 7– 10 = High/Unacceptable Note: risk = likelihood + severity

Page 7 of 10 Project Title: Scarborough Footbridge OS Ref: SE 596 520

ELR: YMS Mileage: 0m 0396yds

DESIGN

DD Ref

Hazard Aspect

Risk Impact

Risk Rating Mitigation measure

Residual Score

Haz Ref L S R L S R

01 Stone Pilasters Errant cyclists injured by riding against the pilasters

4 4 8 Remove existing pilaster to avoid any danger to the cyclist’s directly colliding with the pilaster and getting injured.

1 4 5 DR01

02 Stepped Access Conflict with pedestrian and cyclist on the bridge and at south bank of the river.

5 3 8 Stepped access will be maintained and improved to avoid any direct conflict with the cyclists. Maintaining the stepped access at its present alignment will keep the cyclists and hence the ramps further away from the railway tracks.

1 3 4 DR02

03 Flood Defence

Alteration to the existing flood defence.

3 4 7 Proposed ramp and access to and from the northern need to consider the position of the existing flood defence arrangement. This is to provide a resilient design that will allow continuous access from the Marygate car park to station even during the flood. Also any modification to the existing arrangement will be cost prohibitive.

1 4 5 DR03

04 Bridge Substructure

Overloading existing foundations 4 5 9 Design & Build Contractor needs to be mindful that there is very limited information available for the existing substructures. Therefore the detailed design should be based on the principle that the overall load be limited to match the gross existing dead weight on the bridge abutments and the central pier.

Undertake assessment of the foundation capacities.

If necessary provide additional foundation immediately next to the existing bridge abutments.

2 5 7 DR04

05 Existing Railway bridge

New footbridge railway side parapet intruding railway gauge.

3 4 7 Detailed design should consider the railway gauge. The parapets to be designed to remain clear of the gauge. Presently a Kee-klamp type handrail is in place as fall arrester for the track level works. During the

1 4 5

Likelihood Severity (Health & Safety) Severity (Environmental)

1 = Very unlikely 1 = Minor injury 1 = Minor environmental incident with no legislative breach 2 = Unlikely 2 = Lost time injury 2 = Potential for complaints from local residents, no legislative breach 3 = Likely 3 = Reportable injury/dangerous occurrence 3 = Potential for lost time/complaints from Local Authority for legislative breach 4 = Very likely 4 = Major injury 4 = Minor legislative breach with potential for prosecution 5 = Certain 5 = Fatality 5 = Potential for major environmental incident with high clean up and/or prosecution costs Risk Rating 1 – 3 = Low 4 – 6 = Medium/Tolerable 7– 10 = High/Unacceptable Note: risk = likelihood + severity

Page 8 of 10 Project Title: Scarborough Footbridge OS Ref: SE 596 520

ELR: YMS Mileage: 0m 0396yds

DESIGN

DD Ref

Hazard Aspect

Risk Impact

Risk Rating Mitigation measure

Residual Score

Haz Ref L S R L S R

detailed design if it is considered to replace this handrail, similar safety feature needs to be incorporated in the proposed design.

Network Rail Infrastructure Projects Building & Civil Design Group York ICC, Leeman Road York YO26 4XD T +44(0) 33 085 49678 www.networkrail.co.uk

This document is the property of Network Rail Infrastructure Limited. It shall not be reproduced in whole or part nor disclosed to a third party without the written permission of Network Rail Infrastructure Limited. Uncontrolled copy once printed from its electronic source. Published and Issued by Network Rail Infrastructure Limited, Kings Place, 90 York Way, London N1 9AG Copyright 2015 Network Rail Infrastructure Limited. All rights reserved.

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