AGENDA ITEM 7
BOROUGH OF POOLE
TRANSPORTATION ADVISORY GROUP – 27 OCTOBER 2011
REPORT OF HEAD OF TRANSPORTATION SERVICES
BRIDGE MAINTENANCE
PART OF THE PUBLISHED FORWARD PLAN
NO
STATUS (Service Delivery)
1.
PURPOSE
1.1
To consider the schemes within the Structures Maintenance category of the
2011/12 Transportation Capital Programme
2.
DECISION(S) REQUIRED
It is recommended that the Portfolio Holder be requested to approve:
2.1
The schemes for Ferry Way, Sterte Culvert, and Canford Suspension
Bridge;
2.2
The deferment of the scheme at Creekmoor New Bridge; and
2.3
The associated virement of £230,000 from the Creekmoor New Bridge and
Sterte Culverts to the Ferry Way scheme as described in paragraph 4.2.
3.
BACKGROUND INFORMATION
3.1
Within the Transportation Capital Programme approved at the 24 February
2011 meeting of this Group the Structures Maintenance programme consisted
of the following :
(a) Canford Suspension – repairs / refurbishment of complete structure
(b) Sterte Culvert – clearance of silt / debris from discharge pipes
(c) Creekmoor Bridge – repairs to soffit and sheet piles
This report covers the latest position with respect to these schemes
3.2
Creekmoor New Bridge / Ferry Way Car Park Retaining Wall
3.2.1 Following a recent programme of underwater surveys, it is now apparent
that the deterioration of the sheet piling at Creekmoor New Bridge is not
continuing at its previous rate.
3.2.2 The surveys also included the sheet pile wall at Ferry Way, Sandbanks
which supports the small area of highway / car parking adjacent to the
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chain ferry. This showed that there has been significant deterioration of
these steel sheet piles here since the last inspection 2 years ago. Existing
holes have become larger and new ones have formed causing material
behind the wall to be washed away. Photographs are shown as Appendix
A
3.2.3 A maintenance project for this structure was already planned for next year
2012/2013. However In view of the information now available, it is
proposed to bring the project for Ferry Way Car Park Wall forward to this
year in place of works at Creekmoor New Bridge.
3.2.4 Design of the Ferry Way scheme is currently underway, with tenders being
sought by the end of the year and, subject to being within the available
budget, works will be undertaken during March 2012. While there will
inevitably be some disruption to the public area, this is generally the
quietest period of the year.
3.2.5
3.3
If during the course of the detailed design it becomes apparent that works
cannot be completed within this financial year, a revised completion date
will be notified to this committee. Should it be necessary for work to
continue into April, disruption over the Easter period will be kept to a
minimum.
Sterte Culverts Silt Clearance
3.3.1 Sterte Culverts, located beneath the Esplanade at Sterte were constructed
in 1994, designed to receive highway runoff with a discharge directly into
Holes Bay. The three culverts are 1.75m wide x 1.5m deep box concrete
construction, approximately 120m long.
3.3.2 Inspections over the past few years have identified sediment which is
accumulating in the bottom of the culverts, to a depth of 300mm as
measured at the last inspection in 2009. This sediment is preventing a full
inspection of the culverts, and furthermore is affecting their effective
operation. Clearly as the silt continues to accumulate the cost of removing
it will increase.
3.3.3 There is also a concern that as the amount of material from the highway
accumulates the level of contaminants will increase, eventually reaching a
level at which the material cannot be discharged safely into the harbour.
The costs of any works to remove the material and dispose of it to a
licensed tip would therefore significantly increase.
3.3.4 As the culverts discharge directly into Poole Harbour (SSSI), any works to
remove the sediment needs to be approved by the following
organisations:Environment Agency (EA)
Natural England (NE)
Poole Harbour Commissioners (PHC)
Maritime Management Organisation (MMO)
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CEFAS (Centre for Environment, Fisheries & Aquaculture Science)
3.3.5 The current proposal is to remove the silt by liquefying the material and
discharging it directly into Poole Harbour. In order to progress this a
licence application has been made to the MMO, with samples of the
material having been sent to CEFAS for testing.
3.3.6 As part of the licencing process, Natural England have indicated that they
will impose a restriction on the timing of the works to protect nesting birds.
No works will be permitted over the winter period (November – March)
which means that work on site cannot start until April 2012.
3.3.7 The budget currently allocated for this scheme this year is £150,000.
Subject to the approval of this Group a contract will be let providing
options for cleaning the three of the culverts with works to commence in
April 2012. Options for works to prevent future build up of silt are also
being investigated.
3.3.8 As works cannot be completed this financial year, it is proposed to keep a
budget of £30,000 for 2011/12 and to vire the remaining £120,000 to the
Ferry Way Car Park wall project. Funding to complete the Sterte Culvert
works will be allocated in 2012/13, although depending on the extent of the
works it may be necessary to programme some of the works in future
years if there is insufficient funding available.
3.4
Canford Suspension Footbridge
3.4.1 The scheme was considered by this Group at the meeting on 25
November 2010. Detailed design is currently being undertaken by Dorset
Engineering Consultancy. Consent for the works has been obtained from
the Environment Agency, which includes permission for the structure to be
removed using flotation devices. On the basis that this removes the need
to carry out works on the river bed, the original constraint of carrying out
the works only between 1 May – 31 October no longer applies.
3.4.2 Consultation with the Borough’s conservation and arboricultural officers
has also been undertaken and the extent of the works agreed.
3.4.3 A tender list for the works is currently being drawn up. Subject to the
tender price being within the estimate it is anticipated that the works will be
undertaken during February and March 2012.
4.
4.1
FINANCIAL IMPLICATIONS
The current budget allocation in the 2011/12 approved capital programme
is as follows:
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BRIDGE MAINTENANCE PROGRAMME 2011/12
STRUCTURE
BUDGET
Canford Suspension Footbridge Refurbishment
£75,000
Sterte Culverts Silt Clearance
£150,000
Creekmoor New Bridge Sheet Piles
£110,000
Total
£335,000
4.2
The maintenance scheme for the Ferry Way retaining wall is estimated at
£230,000, and as explained above it is proposed to undertake the works
during this current year.
It is therefore proposed to vire :
 £110,000 currently allocated for Creekmoor New Bridge
 £120,000 from Sterte Culverts Silt Clearance
to enable the new scheme at Ferry Way to proceed.
4.3
£30,000 will remain in the budget for Sterte Culverts Silt Clearance in this
year. The outstanding required to complete the works will be allocated
from the 2012/13 budget ( typical allocation for bridges £330,000 per
annum )
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LEGAL IMPLICATIONS
None
6.
RISK MANAGEMENT IMPLICATIONS
6.1
The undertaking of maintenance works on highway structures in a timely way
ensures that any risks associated with maintaining these significant highway
assets are kept to a minimum, and that furthermore the structures remain fit
for purpose.
7.
EQUALITIES IMPLICATIONS
7.1
Canford Suspension Footbridge
7.1.1 Within the report to this Group on 25 November 2010 regarding maintenance
of this scheme it was stated that the deck of the footbridge is 0.9m wide which
is not Disability Discrimination Act (DDA) compliant.
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7.1.2 Since then investigations have been undertaken to determine what would be
required to provide full compliance. It is clear that this would require an
effectively new bridge to be constructed, creating considerable environmental
and listed structure planning consent issues. Furthermore the additional cost
to this authority would be £50,000 ( DCC have indicated they would not be
prepared to fund anything more than their 50% contribution to the original
maintenance scheme ) for which there is currently no budget available.
7.1.3 The footpath is used mainly for recreational purposes and is generally in itself
not DDA compliant.
7.1.4 On this basis it is proposed that the works proceed on the basis of the original
planned refurbishment of the existing bridge
8.
CONCLUSIONS
8.1
It is recommended that maintenance on highway structures be carried out in
the way described in this report, funded from the Transportation Capital
Programme.
Julian McLaughlin
Head of Transportation Services
Report Author: Lynne Wait
Contact officer: John Rice (Tel: 01202 262111)
Appendix A – Photographs of Ferry Way sea wall
Background Papers:
1. TAG Report 25 November 2010
2. TAG Report 24 February 2011
TAG271011T3E
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