S1 Operational Principles

S1 Operational Principles

S1.1 General

This Specification incorporates new terminology introduced under the European EN 13108 series of standards for asphalt, the term asphalt in this case referring to mixtures of bituminous binder and aggregate. These became effective in January 2008. Readers and practitioners should therefore be familiar with the new terms used in this Specification, as follows:

"asphalt concrete" replaces the previous
(bituminous mixtures)
"coated materials to BS4987"
"base" replaces the previous "base (roadbase)"

Readers and practitioners should note that reference to "asphalt" is NOT limited to "hot rolled asphalt".

S1.1.1 An Undertaker executing road works shall carry out the excavation and reinstatement in accordance with this Specification. Where this Specification allows alternatives, the Undertaker shall select one of the permitted options. Regardless of which alternative is selected, the Undertaker shall guarantee the performance of the reinstatement to the relevant standards, for the relevant guarantee period.

S1.1.2 The reinstatement shall be carried out using a permitted method incorporating the highest degree of immediate permanent reinstatement appropriate, in the opinion of the Undertaker, to the prevailing circumstances.

S1.1.3 An interim reinstatement shall normally be made permanent within six months. This period may be extended, by agreement, for an additional six months. Throughout the period in which an interim reinstatement is insitu, the performance requirement within S2 of this document applies

S1.1.4 The requirements and standards in this Specification apply to roads which are maintainable or prospective public roads. In the case of all other roads, only those relevant parts of this Specification relating to "Surround to Apparatus" and "Backfill" shall apply. Surfacing layers, if any, shall be reinstated, as far as is reasonably practicable, to match the existing construction. In all cases, reinstatement must be undertaken to the reasonable satisfaction of the appropriate Authority.

S1.2 Guarantee Period

S1.2.1 The Undertaker shall ensure that the interim reinstatement conforms to the prescribed standards until the permanent reinstatement is completed, and that the permanent reinstatement conforms to the prescribed standards throughout the guarantee period.

S1.2.2 The guarantee period shall begin on completion of the permanent reinstatement and shall run for two years, or three years in the case of deep openings. It should be noted that completion of the permanent reinstatement, rather than the giving of information to the Authority that the reinstatement is completed, is the event that triggers the start of the guarantee period. Failure to give this information is an offence under Section 129(6) of the Act and it is the onus of the Undertaker to provide evidence of the date of completion of any given reinstatement for liability guarantee purposes.

S1.3 Road Categories

S1.3.1 Roads are categorised by this Specification into five types, each with a limiting capacity expressed in millions of standard axles (msa) as shown in Table S1.1.

Table S1.1 Road Categories
Road Category Traffic Capacity
Type 0 Roads carrying over 30 up to 125 msa
Type 1 Roads carrying over 10 up to 30 msa
Type 2 Roads carrying over 2.5 up to 10 msa
Type 3 Roads carrying over 0.5 up to 2.5 msa
Type 4 Roads carrying up to up 0.5 msa

S1.3.2 Roads carrying more than 125 msa are not included in this Specification. Reinstatement designs for such roads shall be agreed between the Undertaker and the Authority, on an individual basis.

S1.3.3 Road categories defined in Table S1.1 are based on the expected traffic to be carried by each road over the next 20 years. Each Authority shall categorise its road network on this basis and the Undertaker shall use the most current information available from the Authority. Where an Authority does not classify its roads as required by this Specification, the Undertaker shall determine the classification of these roads, as necessary, and provide a copy of the classification to all parties concerned.

S1.3.4 Valid traffic flows shall be assessed by accurately monitoring commercial vehicles in excess of 1.5 tonnes unladen weight. Traffic growth rates shall be determined from the average of at least three separate assessments carried out over at least three years. Where traffic growth rates are expected to increase significantly, as a result of changing traffic patterns, only predictions generated from a recognised planning process may be used. A zero traffic growth rate shall be assumed until accurate information is available.

S1.3.5 The reinstatement shall be designed using materials specified in Appendices A1, A2, A9 and A11. The overall layer thickness shall be as specified in Appendices A3 to A7 for the various categories of carriageway, footway, footpath, cycle track, verge or unmade ground, and shall be compacted to the requirements of Section S10 and Appendix A8.

S1.4 Footway, Footpath and Cycle Track Categories

Footways, footpaths and cycle tracks are categorised by this Specification as follows:

S1.4.1 High duty - those designated as principal routes and used by an exceptionally large number of pedestrians and/or cyclists.

S1.4.2 High amenity - routes surfaced with one of the following surfacings, and which have been constructed and maintained to a high standard:

1) Surfaces chosen specifically for decorative purposes, with special colours, textures or surface finishes.

2) Flexible surfaces with a particular texture or distinctive coloured finish. Such surfaces will usually be situated in conservation, leisure or ornamental areas, pedestrian precincts or where an Authority has maintained high quality paving.

S1.4.3 Other - those that are neither high duty nor high amenity.

S1.4.4 Where a Road Authority is able to demonstrate that a high amenity or high duty footway has been constructed and maintained to a standard in excess of that prescribed in Sections S2.2 and S2.3 and registered accordingly then in these instances the reinstatement shall meet the Road Authority's standard of maintenance and their declared intervention criteria.

S1.5 Excavation and Trench Categories

Excavations and trenches are categorised by this Specification as follows:

S1.5.1 Small Excavations - all openings with a surface area of 2 square metres or less. For the purposes of this Specification, test holes up to 150 mm diameter are not excavations and shall be reinstated in accordance with the requirements of Section S11.

S1.5.2 Narrow Trenches - all trenches of 300 mm surface width or less, with a surface area greater than 2 square metres.

S1.5.3 Deep Openings - all excavations and trenches in which the depth of cover over the buried apparatus is greater than 1.5 metres. Trenches with a depth of cover that is intermittently more than 1.5metres for lengths of less than 5 metres are not deemed to be deep openings.

S1.5.4 Other Openings - all excavations and trenches with a surface area greater than 2 square metres.

S1.6 Alternative Options

S1.6.1 (i) An Undertaker may adopt an alternative Specification for materials, layer thickness and compaction methods to take advantage of new or local materials and/or alternative compaction equipment, subject to the prior agreement of the Authority, which shall not be unreasonably withheld. There shall be no departure from the performance requirements during the guarantee period.

(ii) An undertaker may use alternative excavation processes and equipment e.g. large diameter coring, subject to the prior agreement of the Authority.

(iii) Local agreements under this section only become valid when recorded using the procedure set out in Appendix 9.6

S1.6.2 Recycled, secondary or virgin materials, or any combination thereof, is permitted by this Specification, provided they meet the performance requirements and any compositional requirements detailed in this Specification for the relevant material layer.

S1.6.3 Stabilised materials shall be permitted for use as surround to apparatus, and at backfill and sub-base layers, provided they meet the relevant performance requirements of this Specification.

S1.6.4 (i) Alternative Reinstatement Materials are described in Appendix A9.

(ii) Approval Trials under Appendix 9 are recorded centrally in accordance with Appendix 9.6. This provides a record of new materials, their specifications and restrictions and those Authorities which permit them to be used.

S1.7 Immediate Works

S1.7.1 There are circumstances when it is necessary to immediately reinstate an excavation, regardless of the material availability etc., purely to enable traffic or pedestrian movement to occur on a traffic sensitive route. In such circumstances, reinstatements may be completed using excavated or other materials, properly compacted in 100 mm layers, with a minimum surfacing thickness of 40 mm of bituminous material.

S1.7.2 All materials so placed which do not comply with the requirements of this Specification shall be re-excavated and reinstated, to the appropriate interim or permanent standard as specified, as soon as practicable, but within 10 working days, or as agreed with the Authority following the completion of the immediate works.

S1.8 Apparatus within Road, Footway and Cycle track Structures

S1.8.1 Undertakers apparatus greater than 20mm external diameter will not be permitted within road, footway or cycletrack structures unless special circumstances exist (for example shallow cover over culverted watercourses, utility apparatus, etc). In these special circumstances the utility must consult with the Authority whose approval shall not be unreasonably withheld.

S1.8.2 Apparatus of 20 mm external diameter or less shall not be permitted above or within 20 mm of the following levels within a road structure, see Figure S1.1:

1) The Base/binder course interface in a flexible structure.

2) The underside of the concrete slab in a rigid structure.

3) The underside of the complete construction (formation layer) in a modular structure (refer to Appendices A6.1 to A6.3).

Figure S1.1

S1.8.3 Where other existing apparatus or surrounds occur within the road structure, the method of reinstatement shall be determined by agreement.

S1.9 Geosynthetic Materials, Geotextiles and Reinforcement Grids

S1.9.1 Where the Authority knows of the existence of any of the above materials in areas likely to be affected by an Undertaker's work, they should inform the Undertaker, prior to the commencement of works, and/or place information detailing these as a Special Engineering Difficulty on the Gazetteer, so that an appropriate reinstatement method can be agreed.

S1.9.2 If the Undertaker is not informed of the existence of any of the above materials prior to the commencement of his works, but encounters them during the works, he should inform the Authority immediately so that an appropriate reinstatement method can be mutually agreed. In these circumstances, the Undertaker shall not be liable for the repair of any damage caused to geosynthetic materials, geotextiles or reinforcement grids if their existence was not known.

S1.10 Trees

S1.10.1 When working near trees, the National Joint Utilities Group (NJUG) publication Volume 4 "NJUG Guidelines for the Planning, Installation and Maintenance of Utility Apparatus in Proximity to Trees" should be followed. The publication gives comprehensive advice and should be followed in its entirety. Relevant extracts are reproduced in Notes for Guidance NG1.10.

S1.10.2 In addition to the recommendations of the NJUG guidelines, the use of tree root barriers may be considered. Specialist advice from an Arboriculturist should be sought.

S1.11 Conciliation and Arbitration

S1.11.1 This Specification is intended to provide sufficiently detailed guidance to enable agreement on its operation and implementation to be reached at local level. Authorities and Undertakers should always use their best endeavours to achieve a solution to disputes without having to refer them to conciliation. This might be achieved by referring the issue to management for settlement.

S1.11.2 If, however, agreement cannot be reached, the provisions set out in the Code of Practice for the Co-ordination of Road Works and Works for Road Purposes and Related Matters should be followed.