Agenda item

Report of the Director of Environment and Resident Experience. To be introduced by the Cabinet Member for Culture, Communities & Leisure and the Assistant Director for Direct Services.

 

This report seeks approval to enter into contract with a contractor to deliver the replacement bridge and associated works pertaining to Stanhope Road Bridge.

The Cabinet Member for Culture, Communities & Leisure introduced the report which sought approval to enter into contract with a contractor to deliver the replacement bridge and associated works pertaining to Stanhope Road Bridge.

 

The location and area of the bridge were outlined by the Cabinet Member and it was noted that following structural inspection and assessment, Stanhope Road Bridge was identified as needing urgent intervention with replacement being the most appropriate option.

 

The recommendations within the report for the appointment of the preferred bidder to deliver the Stanhope Road Bridge replacement works ensured that this essential scheme was delivered.

 

The project aimed to improve the overall quality of Haringey’s green transport network and encourage active travel, as well as enhancing resident experience by providing a connection to green spaces, as well as improve accessibility by means of a ramp to provide step-free access from Stanhope Road up to the Parkland Walk

 

In response to questions from Councillor Cawley-Harrison the following was noted:

-       12 trees agreed to be planted

-       The bridge works were set to begin in February 2024 and, with the landscaping work, would last approximately a year.

-       With regard to mitigating plans for accessibility while the works on Stanhope Bridge were carried out, it was noted that there were plans for stop points on Parkland Walk both sides of Stanhope Road near the existing bridge.

 

Further to considering exempt information at item 24,

 

RESOLVED

 

1. To approve the award of the contract for ‘Stanhope Road Bridge Replacement Works’ to Bidder 1 for the sum of £3,036,620.93 +VAT as permitted under Contracting Standing Order (CSO) 9.07.01(d).

 

2. To approve the additional provisional sum making up the scheme risk and contingency, as detailed within the (exempt) Part B of this report.

 

3. To authorise the issue of a letter of intent (LOI) for the amount detailed within the (exempt) Part B of this report, as permitted under CSO 9.07.3.

 

Reasons for decision

 

There are significant defects to the masonry abutment and signs of movement to the substructure of Stanhope Road bridge. The structure was placed under a movement monitoring regime to track the deterioration in these defects and temporary props were installed to provide additional support. Ongoing monitoring since 2020 shows there is a continued decline in the condition of the bridge structure, with critical defects expected to be reached by 2027.

 

A competitive tendering exercise was undertaken to secure a contractor to

deliver the "Stanhope Road Bridge Replacement Works". Through this process, Bidder 1 scored the highest and demonstrated that it should be awarded the contract.

 

The tender sum submitted by Bidder 1 is less than the pre-tender estimate prepared by an external cost consultant and is therefore deemed to be good value.

 

By awarding the contract to Bidder 1, the Council is securing the delivery of the "Stanhope Road Bridge Replacement Works". It is intended that the main bridge works be conducted between February 2024 and November 2024.

 

The works delivered by the scheme are essential to replace the existing bridge that has passed its design life and will minimise maintenance costs in the long term. The works will also result in the removal of the existing height restrictions under the bridge to future-proof the structure and reduce the risk of vehicle strike.

 

As part of the scheme delivery, an access ramp compliant with the Equality Act 2010 will be installed to the east embankment to allow step free access from Stanhope Road up to the Parkland Walk.

 

The new bridge will also create a better environment for walking along Stanhope Road by removing the existing footway restrictions caused by the structural propping located on the eastern footway under the bridge (see below images). This is important as Stanhope Road is a busy route for pedestrians that is frequently used by school children attending the nearby schools.

 

Figure 1: View looking north along Stanhope Road showing temporary structural props on east footway.

Figure 2: View looking south along Stanhope Road showing temporary structural props on east

footway.

 

Alternative options considered.

 

Option 1 – Do nothing. Do not appoint a contractor to undertake this work.

Pursuing this option will fail to address the critical defects identified during the

bridge inspection and assessment process. Ongoing monitoring since 2020

shows that the bridge is in a deteriorating state and cannot be left in its current condition. Without intervention, the bridge will become unsafe and require closure of the Parkland Walk and Stanhope Road to all traffic. It is essential to public safety that the defects are addressed.

 

There are risks associated with not undertaking the repairs - a delay to address the issues will result in increased costs by addressing further deterioration through emergency works.

 

This option is not recommended.

 

Option 2 – Do not proceed with the bridge replacement scheme. Carry out repairs instead.

 

Alternative options to replacing the structure were considered during the

feasibility design stage. There are significant risks associated with the feasibility options for retaining the existing abutments - those options included brickwork repairs and construction of a new bearing shelf, as well as the installation of anchors or underpinning the abutments with piles and needle beams.

 

Repairing the substructure is a complex operation; it is difficult to predict how

the bridge abutments will behave in the future and further remedial

works/demolition could be required. This is due to the unknown extent of the

cracks within the abutments and the medium/high susceptibility of the bridge to changes in the moisture content of the soil. Furthermore, it was found to be

difficult to establish the geometry and extent of the cracks within the bridge

during investigations without risking further destabilisation of the substructure.

 

In all situations, the bridge deck requires jacking up and lifting off the structure

to install new bearing shelves and bearings, followed by reinstallation of the

bridge deck. Replacing the bridge deck will achieve a 120-year design life of

the structure and remove the need for repairs for the foreseeable future.

 

This option is not recommended.

 

Option 3 – Do not proceed with the bridge replacement scheme. Demolish the structure and replace with an ‘at-grade’ pedestrian crossing.

Alternative options to replacing the structure were considered during the

feasibility design stage. Whilst demolishing the structure minimises any ongoing future maintenance costs, it fails to provide a connected active travel corridor along the Parkland Walk and detracts from the green space.

 

A community consultation undertaken during the project development in

December 2020 identified that 86% of respondents wanted the bridge retained and not removed.

 

Replacing the structure with an ‘at-grade’ crossing increases the risk of harm to pedestrians and cyclists crossing the public highway. Secondly, it will be difficult to achieve an accessible ramp without significant ground works that will be costly and disruptive to the nature reserve setting and will likely require

additional trees to be felled to accommodate the significant earthworks.

 

By removing the bridge and replacing with graded ramps, the Parkland Walk

will be split, and a barren area will be created in the green corridor. This will

have a detrimental effect on local fauna that inhabits the nature reserve.

 

This option is not recommended.

 

Option 4 – Return to the market to re-tender.

The project is time-sensitive due to continuing deterioration of the defects and

the bridge cannot be left in its current condition. Without intervention, the bridge will become unsafe and require closure of the Parkland Walk and Stanhope Road to all traffic – representing additional costs to the Council with no realisable benefit. It is essential to public safety that the defects are addressed.

 

The open tender process generated five bona fide bidders, all of which were

within the pre-tender estimate prepared by an external cost consultant.

 

Through their response to the tender quality questions, Bidder 1 clearly

demonstrated that it could undertake the project and understood the Council's

requirements. Bidder 1 also submitted a price in line with the pre-tender

estimate and competitor bids.

 

It is considered that there is nothing to gain by returning to the market. Prices

are most likely to increase through inflation and additional costs will arise from

safety measures associated with a failing structure.

 

This option is not recommended.