Surrey HIGHWAYS
structures GROUP
TRANSPORTATION ASSET MANAGEMENT
STRUCTURES ASSET MANAGEMENT PLANNING
Project Title: Bridge Management
Document Title: Transportation Asset Management
Structures Asset Management Planning
Client Reference: S/TAA/8
Date: 14 March 2008
Prepared By: Print Hugh Brooman
Sign ......
Authorised By: Print Graham Cole
Sign ......
Amendment List
Iss. / Rev. / Iss. / Rev Date / Remove / InsertPage / Iss. / Rev. / Page / Iss. / Rev.
Issue 00 / July 2004 / All pages / 00 / All pages / 01
0201SF10 07/08/02
Filename: S:\GENERAL\AMG\Structures\\lifecycle.doc
Issue No. 01 Page 23 of 51 Document No. 2227/17
SURREY HIGHWAYS STRUCTURES ASSET MANAGEMENT PLANNING
STRUCTURES GROUP
Contents
1 Introduction
2 Strategic Goals and Objectives.
3 Asset Inventory
4 Current Performance
5 Future Demand
6 Performance Targets and Levels of Service
7 Performance Gaps
8 Lifecycle Plans
9 Value Management and Risk Management
10 Asset Valuation
11 Work Plan and Financial plan
12 Sustainable Development
13 Improvement Plan
14 References
Issue No. 01 Page 23 of 51 Document No. 2227/17
SURREY HIGHWAYS STRUCTURES ASSET MANAGEMENT PLANNING
STRUCTURES GROUP
______
1 INTRODUCTION
The Structures Group of the Surrey Highways Service undertakes the management of the highway structure asset. Highway structures are defined as any bridge or other structure that impinges in any way within the footprint of the highway or that materially affects the support of the highway or land immediately adjacent to it that meets certain dimensional criteria. Highway structures include bridges, culverts, subways, footbridges and retaining walls. An important Structures Group goal is to:
“document that the assets for which it is responsible are being preserved at, or above, a series of key performance indicators originally established for the assets”
We will do this by preparing and working to the Asset Management Planning process that is set out in this document. This is the second edition of this document – the first was prepared in July 2004. It is recognised that the preparation of an Asset Management Plan is a continuous improvement process and it is anticipated that further versions of this Asset Management Planning document will be issued on an ongoing basis.
‘It is widely recognised that a well managed transport infrastructure is vital to the economic stability, growth and social well being of a country. Bridges and other highway structures are fundamental to the transport infrastructure because they form essential links in the highway network. It is not therefore in the public interest to allow highway structures to deteriorate in a way that compromises the functionality of the highway network, be it through restrictions or closures caused by unsafe structures or the disruption of traffic through poor planning of maintenance work.’ [Ref 1]
This Asset Management Planning document is based on the format recommended by the Code of Practice for the Management of Highway Structures (the Code) [Ref.1]. This document is part of a suite of resource management plans that support the corporate objectives of the County Council and the operational priorities of the Group:
· Surrey Highways Service Business Plan
· Annual Group Management Plan
· Quality Management System (QMS) documentation
The relationship between these various documents is shown in Figure 1. The overall process involved in the Management of Highway Structures is shown in Figure 2. A comprehensive review of the work of the Structures Group was carried out in the first quarter of 2008 and some of these processes will change in the near future.
Fig.1 – Key Documentation
Fig. 2 – The Management of Highway Structures
Note: Damage to County Property (DCP)
2 STRATEGIC GOALS AND OBJECTIVES
The overall policies and aims of the County Council are currently set out in the Manual of Policies and Standards (Maps) document. In addition, the Local Transport Plan (LTP) also sets out various criteria and objectives within the ‘Planning and Maintaining the Highway Network’ chapter. Successful management of the bridge stock is fundamental to the implementation of the LTP. There are five main themes within the LTP and the Structures Group contributes to these as follows:
Economy: the strategy takes account of the business needs of local communities in prioritising bridge management activities. Where weak bridges are on routes which provide access to business parks etc. weight restrictions would have a detrimental effect on the economy, so strengthening schemes receive a high priority rating.
Safety: the strategy principally contributes to this objective by ensuring that minimum levels of safety are maintained. In maintenance, the repair of safety-related defects and damages takes priority. In bridge strengthening schemes, highway safety improvements are included where possible.
Integration: a robust bridge stock is needed to deliver network flexibility requirements and accommodate bus routes which may be introduced to improve transport integration.
Accessibility: in strengthening and refurbishing, accessibility for vulnerable users is improved by adding footpaths and increasing width whenever possible. The maintenance of subway pumps, anti-slip surfacing, handrails and graffiti clearance are important to provide a pleasant environment, so that pedestrians are encouraged to use subways and footbridges. The 2002 Audit Commission Best Value inspection of the Transportation Service commended the Structures Group on the inclusion of parapet enhancement measures in bridge strengthening schemes.
Environment: environmental considerations, heritage value and conservation are taken into account in the selection of materials and methods of working for strengthening and reconstruction projects.
The Highways Service priorities for 2007/08 include to ‘Improve the Highway Network’, ‘Improve Road Safety and Security’, ‘Enhance the Environment and Quality of Life’ and to ‘Provide Services to People and Communities in a Way that Meets their Needs’. The work of the Structures Group contributes to all of these Service wide priorities.
The Highways Act 1980 requires that roads are maintained to allow the passage of all Construction and Use vehicles i.e. those up to 40/44 tonnes. Therefore, the primary service standard is to maintain bridges to allow the passage of such vehicles, including smaller vehicles with 11.5 tonnes axles, unless a permanent weight restriction has been imposed at a particular bridge.
In particular, Section 41 (1) of the Highways Act states:
The Authority who are for the time being the highway authority for a highway maintainable at the public expense are under a duty, ……, to maintain the highway.
The Act includes provisions for enforcing liability for maintenance (Section 56) that can be determined by a magistrates court. The Act provides a general power to improve highways (Section 62) including the provision of subways (Section 69), footbridges (Section 70) and the construction and reconstruction of bridges (Sections 91 and 92). More detailed sections of the Act grant the power to construct bridges over navigable water courses (Section 106).
The Act grants the power to remove unauthorised structures (Section 143), to licence the construction of a bridge over the highway (Section 176) and to control the construction of scaffolding (Section 169) and cellars (Section 179). The Act also grants powers to control the construction of retaining walls near streets (Section 167). Furthermore, bridgeworks shall not be carried out unless approved by the county council (Section 195), a duty delegated to the Technical Approval Authority.
The serviceability standards for the bridge stock will be maintained by seeking to achieve average and critical values of between 90 and 94 in accordance with the CSS Bridge Condition Indicator system [Ref. 2]. This reflects the usual practice of adopting a ‘good’ standard as an optimum level of service determination [Ref. 3]. Service standards will be further developed as the family of national performance indicators described below is implemented.
General consultation with the public regarding their interest in highway matters rarely includes reference to highway structures. Public consultation, which supported the development of the first edition of the Hertfordshire Asset Management Plan, showed that maintaining the safety of the bridge stock was a primary public objective and Surrey residents are unlikely to have different views. Local scheme specific consultations show that the public are rightly concerned about the way works are carried out and how they are involved in the process. We have local performance indicators that seek to address this matter.
3 ASSET INVENTORY
This asset grouping comprises bridges (both vehicular and pedestrian), culverts, subways (and their associated pumps) and retaining walls. Bridges are of various types and spans but their construction is mainly concrete, steel or masonry / brick. The asset group includes right of way structures as well as those on main roads. In particular, highway structures are specifically defined as:
· Bridges, culverts, chambers or subways under or over the highway with a composite span of 0.9 metres or more.
· Retaining walls, where the height of retained fill measured between lower ground level and upper ground level is 1.37 metres (4’ 6”) or more.
· Miscellaneous structures:
· Reinforced earth embankments 1.37 metres or more in height and where the angle of the side slopes is greater than the natural angle of repose of the embankment material
· High mast lighting columns 20 metres or more in height
· Structural aspects of sign and signal gantries as defined in HA Standard BD63
· Structural aspects of traffic signal mast arm assemblies as described in HA Standard BD88
We carry out inspections of all SCC owned highway structures. Within the County there are also a significant number of structures carrying highways and other transport systems that are owned by other statutory bodies such as the Highways Agency, Network Rail and utility companies. We carry out superficial inspections of these structures, where appropriate, to safeguard highway users.
Details of the asset are recorded on the Bridge Management System (BMS), supplied by Futuris, and known as Bridgestation. Much of this data is readily accessible via the County GIS system or by SAMS. The extent of the current inventory is indicated in Tables 1, 2 and 3. An indication of construction materials and year of construction are included in Tables 4 and 5.
The Project Manager makes additions and changes to the asset inventory following significant maintenance work, completion of developer schemes, creation of new assets or ‘discovery’ of an existing bridge or retaining wall. The inspection process is also used to check the validity of data held on individual structures. Details of the attributes recorded during the inspection process are included in section 4.1. The reliability of bridge data is high but there is still a need to improve the extent of the data regarding retaining walls. Monies had been allocated in 2007/08 to continue additional survey work for this asset sub-group but have now been withdrawn.
Table 1 – Asset by Type and District (all owners)
Bridge / Culvert / Footbridge / Subway / Ret Wall / Other / TotalElmbridge / 70 / 11 / 33 / 5 / 4 / 2 / 125
Epsom and Ewell / 29 / 7 / 14 / 1 / 11 / 3 / 65
Guildford / 192 / 59 / 133 / 17 / 47 / 15 / 463
Mole Valley / 166 / 44 / 220 / 9 / 18 / 7 / 464
Reigate and Banstead / 90 / 22 / 44 / 8 / 25 / 5 / 194
Runnymede / 47 / 17 / 40 / 1 / 2 / 0 / 107
Spelthorne / 55 / 20 / 34 / 9 / 1 / 1 / 120
Surrey Heath / 61 / 16 / 49 / 7 / 4 / 9 / 146
Tandridge / 122 / 56 / 191 / 3 / 21 / 5 / 398
Waverley / 157 / 65 / 181 / 2 / 38 / 1 / 444
Woking / 55 / 17 / 43 / 1 / 10 / 1 / 127
1044 / 334 / 982 / 63 / 181 / 49 / 2653
Source: Bridge Management System (May 2007)
Table 2 – Asset by Type and Road Hierarchy (all owners)
Bridge / Culvert / Footbridge / Subway / Ret Wall / Other / TotalPrimary / 73 / 28 / 12 / 21 / 27 / 10 / 171
Principal / 123 / 55 / 21 / 13 / 45 / 10 / 267
Non Principal / 223 / 91 / 18 / 6 / 35 / 7 / 380
Unclassified / 264 / 93 / 11 / 6 / 62 / 15 / 451
Row / 294 / 63 / 878 / 8 / 12 / 6 / 1261
Private / 27 / 2 / 2 / 0 / 31
Other / 40 / 2 / 40 / 9 / 1 / 92
1044 / 334 / 982 / 63 / 181 / 49 / 2653
Source: Bridge Management System (May 2007)
Table 3 – Asset by Type and Owner
Bridge / Culvert / Footbridge / Subway / Ret Wall / Other / TotalSCC (Structures) / 544 / 296 / 565 / 43 / 153 / 31 / 1632
Network Rail / 357 / 2 / 48 / 19 / 10 / 436
Other / 143 / 36 / 369 / 1 / 28 / 8 / 585
1044 / 334 / 982 / 63 / 181 / 49 / 2653
Source: Bridge Management System (May 2007)
Table 4 – SCC Asset by Construction Material (approximate)
Prestressed / Reinforced Concrete / Metal Troughing / Steel Composite / Lattice Plate and Steel Girders / Masonry Arches / Timber46 / 347 / 46 / 24 / 95 / 433 / 457
Source: Adapted from Ref.4
Table 5 – SCC Asset by Year of Construction (approximate)
Pre 1820 / 1820 - 1840 / 1840 – 1860 / 1860 - 1880 / 1880 - 1900 / 1900 - 1920 / 1920 - 1940 / 1940 - 1960 / 1960 - 1980 / 1980 - 2000100 / 100 / 150 / 200 / 200 / 225 / 150 / 100 / 100 / 123
Source: Adapted from Ref. 4