Agenda item
BRIDGE MAINTENANCE STRATEGY
- Meeting of Performance Scrutiny Committee, Thursday, 26 January 2017 9.30 am (Item 6.)
- View the declarations of interest for item 6.
To consider a report by the Senior Engineer- Highways and Environmental Services (copy enclosed) to aid in understanding the risks that the current condition of the Country’s Highway Structure infrastructure poses, and to enable scrutiny of the Council’s proposed strategy to manage the identified risks.
11am – 11.45am
Minutes:
The Lead Member for
Public Realm introduced the report (previously circulated) outlining the method
by which the Council managed its highway structure assets and explained how it
intended to manage its current backlog of work in relation to those structural
assets. Via a PowerPoint presentation a Senior Engineer – from Highways
and Environmental Services gave members an overview of the County’s approach to
managing its Highway Structures. He outlined the definitions for the
different highway structures which made up the Council’s Highways Structures
estate along with the number of structures in each category:
·
150
highway bridges (53 of which were listed and a further 6 were scheduled);
·
258
culverts;
·
in
excess of 300 retaining walls; and
·
more
than 300 a Public Right (PROW) of Way bridges
If the Council had
to replace all of the above it would cost it in the region of £313m. In
addition to the Highway Act 1980 the Council also had a duty to maintain all
scheduled or listed monuments (including bridges).
The Senior
Engineer:
·
outlined
the Asset Management Process followed by the Council and the myriad of Advice
Notes and BSEN safety standards with which it had to comply;
·
detailed
Denbighshire’s Highway Asset Management Plan (HAMP) which set out local
standards and the risk based approach adopted to the frequency of inspection –
this approach, also adopted by other County Highway Authorities and the North
and Mid Wales Trunk Road Agency, had saved the authority a substantial amount
of money compared to complying with National Standards whilst not compromising
asset users’ safety;
·
outlined
the amounts of funding allocated from within the Highway and Environmental
Service’s Revenue and Block Capital budget for 2016/17 for highway structure
management and advised that this equated to £445K;
·
provided data on the number of structures which
had been assessed as weak structures, some of which had already been placed
under weight restriction orders. Details were given on the various weight
restrictions usually applied on structures and the types of vehicles which
would be affected by different restrictions. Whilst weight restrictions
were applied on safety grounds they could potentially have an adverse effect on
residents, business, community life and emergency vehicles’ access to areas and
properties;
·
displayed
photographic evidence of different highway structures and the various types of
erosion/material deterioration incurred and repair undertaken or required on
the a number of structures across the county;
·
advised that the appendix to the report
detailed both the revenue and capital costs associated with the structures in
the proposed Highway Structures Backlog Works Project. The estimated cost
of this project would be circa £6m over a 10 year period and would be jointly
funded from the Highway Block Capital Budget, which had been increased by
approximately £320K per annum. Undertaking the project over a 10
year period would ensure that other projects funded from within the Highway
Block Capital Budget would not be adversely affected too much by having funding
diverted from them to the structures project. During the course of this
work bridges and retaining walls would be restricted in order to reduce the
rate of deterioration and ensure that they did not collapse. It was also
proposed to increase the revenue budget to support the backlog programme and to
maintain a planned preventative maintenance programme. A number of
efficiency measures, including employing specialist staff rather than procuring
services from external specialists, were being explored in order to realise
value for money during the course of the project. The remainder of the
proposed budget requirement would be subject to an additional capital bid in
due course;
Responding to
members’ questions the Lead Member, Senior Engineer and Highway Service
Managers advised that:
·
the
prioritisation list for maintenance work on structures was flexible and was
subject to change on a regular basis due to sudden changes in their material
conditions i.e. severe weather/flood damage; structural damage caused by
vehicles etc.;
·
issues
such as third party ownership and access to some structures for maintenance
work need to be worked through;
·
structural
assessments were generally undertaken using mathematical modelling ;
·
it was only when assessing structures that the
actual extent of damage/erosion could be fully confirmed. It was during
such assessments that engineers also could establish whether structures were
actually built on much earlier structures across a river etc.;
·
very
few councils met the National Standards for Highway Structures, the majority
undertook a risk based approach towards their asset management;
·
scour
was a major problem as it was undermining the foundation of a number of
structures;
·
the
loading format for agricultural vehicles was ‘shared’ more evenly compared to
Heavy Goods Vehicles (HGVs) and consequently less highway structure damage was
attributed to them;
·
a regular programme of maintenance was
undertaken on the county’s largest bridge, the bridge spanning the river Clwyd
on the Rhuddlan bypass. Modern bridges such as
this one had been designed to have a 120 year lifespan, nevertheless they would
require regular maintenance during their lifetime;
·
Cadw had provided a financial contribution towards
the work undertaken on the river Elwy Bridge at the bottom of the High Street
in St. Asaph;
·
the
old bridge over the river Clwyd in Rhuddlan, now that
it had been restricted to single lane traffic, was not considered to be at
immediate risk as it was the external 19th century steel widening
which was the cause of concern, not the earlier stone structure which was also
listed;
·
the
benefits of dredging rivers below bridges had to be assessed on a bridge by
bridge basis, as in some cases this could potentially cause more problems in
the long term;
·
a high level of trust existed between the
Council’s highways officers, heritage officers and Cadw
which assisted repair work etc. to be undertaken swiftly when necessary, as
happened when Pont Nantglyn suffered vehicle
damage. The level of mutual trust between all parties ensured that the
bridge was repaired within a short period of time and reduced the disruption
for residents and local users;
·
a
number of meetings had taken place between Finance and Highways officers with a
view to drawing up a deliverable backlog works plan, based on service
efficiencies and a long-term spend to save strategy without the need to apply
for prudential borrowing;
·
officers
had considered a 5 year backlog works plan but this would have incurred
significantly higher costs;
·
officers
were in regular contact with neighbouring counties regarding conditions of
structures which spanned rivers on the county’s boundaries and which served as
access routes to and from the county e.g. Pont y Ddôl,
in the Trefnant ward;
·
the Council did inform a number of satellite
navigation programmes providers once weight restrictions were place on
structures or when any legal notifications relating to the highway system were
published. It was the provider’s responsibility to update its sat nav programmes;
·
third party owners of bridges had the same
responsibilities as the Council to maintain their assets. However the Transport
Act of 1968 placed some financial liabilities on councils for strengthening
some third party owned bridges; and
·
the Council erected advisory signage where
restrictions etc. were placed.
The Committee’s
representative on the Strategic Investment Group (SIG) confirmed that SIG had
supported the proposals submitted for the Highways Structure Backlog Works
Project and was recommending that County Council should approve them.
Members thanked
officers for an extremely informative presentation and acknowledged that a
staggering amount of investment would be required to raise all structures to
National Standards. They were therefore of the view that the managed
approach suggested in the report was a logical way of addressing the backlog
and the risks identified. The Committee:
Resolved: - to support the approach being taken by
the Service to manage the backlog of works in relation to highway structures
assets as per the suggested Highway Structure Backlog Works Project.
Supporting documents:
-
Bridges Report 260117, item 6.
PDF 103 KB
-
Bridges Report 260117- App 1.docx, item 6.
PDF 86 KB
-
Bridges Report 260117- App 2, item 6.
PDF 424 KB