DS-4.9 Further Considerations

The following shall also be considered as part of the design process:

DS-4.9.1 Bridges.
DS-4.9.2 Culverts.
DS-4.9.3 Urban Roadside Barriers and Guardrail Design.
DS-4.9.4 Streetscaping.
DS-4.9.6 Network Utilities.
DS-4.9.7 Road Zone Occupancy.

DS-4.9.1 Bridges

The following shall apply:

Concept approval is required from Council before undertaking bridge design.
Detailed design shall be required at the time of Development Works Approval. Where no Development Works Approval is required as part of a Resource Consent, then Council approval shall be obtained at a time required by Council and before construction of the system.
Bridge design shall conform with the technical requirements of NZTA Bridge Design Manual and be undertaken by an appropriately qualified Chartered Professional Engineer. Reference shall also be made to the Austroad Guides AGBT series for bridge technology.
The width between kerbs and wheel guards shall be in accordance with the NZTA Bridge Design Manual.
All bridges, box culverts and other culverts over 1.0mØ may be subject to a building consent under the Building Act.
Bridges shall be designed to:
1. Be capable of carrying a design loading of HN-HO-72 (public road bridges).
2. Be capable of carrying a design loading of 0.85 (HN-72) (private road bridges) and as shown in the TNZ Bridge Manual: Appendix D :Lightly Trafficked Rural Bridges, June 2003.
3. Have bridge clearances to waterways that shall be approved by Bay of Plenty Regional Council but shall provide not less than 600mm freeboard for a 1% AEP flood event.
4. Provide full clearance for the passage of all vehicles permitted to operate on public roads under the Transport Act 1962, when bridges are provided above traffic lanes.
5. Provide safe passage of all pedestrians and cyclists.
Where bridges exist along private way/ROW alignments that are to be upgraded for private ways approved as a condition of Resource Consent, the bridge shall be examined by a Chartered Professional Engineer who shall determine:
1. The capability of the bridge structure and foundations to support the design loadings (or restricted loadings).
2. The serviceability of the structure and what measures may be required to upgrade the bridge to last another 50 years.
3. Appropriate signs to advise of loading and speed limitations.
In some circumstances on private ways an alternative crossing such as a ford may be required for vehicles which exceed width or loading limitations.
1. For a culvert, the design shall allow for the passage of a 10 year flood event without heading up, and for a 100-year flood by heading up to a maximum level 0.5m below the road surface as per the NZTA Bridge Manual.
For roads with a use of less than 750vpd as a minimum, the design shall allow for the passage of a 10 year flood and heading up to a maximum level of 0.5m below the road surfaces and for a 100 year flood by overtopping the embankment to a maximum depth of 0.2m. Where the road crosses a defined flood plain and overtopping is to be provided for, specific design shall be provided to the satisfaction of Council. If the heading up condition is considered, the design shall ensure embankment stability under flood conditions and adequate protection to safeguard against piping. This clause includes accessways and rights of\- way. Heading up shall be considered in all cases where fallen trees are able to enter the water course.
In all cases where heading up or overtopping is a design feature, attention shall be given to back water effects upstream to ensure that adjoining land is not adversely affected by flooding.
Culverts beneath carriageways shall not be less than 300mmØ.
Installation of bridges or culverts on natural watercourses are generally subject to a Bay of Plenty Regional Council Resource Consent or, in some cases, the works may be covered as a Permitted Activity. Design and construction of these shall comply with all requirements of the Resource Consent or permitted activity criteria.

The advice of Bay of Plenty Regional Council shall be sought at an early stage in the design process.

For roads to be vested in Council, existing bridges or culverts not meeting this standard shall be upgraded to the standard or replaced with structures complying with the standard.

DS-4.9.2 Culverts

Drawing Ref: T443

The following shall apply:

Culverts shall cross the road as directly as possible and in no case at less than 60° to the road centreline.
The inlet and outlet of the culvert shall be at least 1.5m beyond the feather edge and preferably further to reduce the traffic hazard and provide adequate support to the road shoulder.
Culverts shall be reinforced concrete. Where alternate materials are being proposed, this will require specific approval from Council.
Care shall be taken to prevent scour in channels downstream of culvert outfalls and the construction of stormwater fluming may be necessary. Where culvert or road cut out discharges are to occur into private land, the written approval of the private landowner shall be obtained before construction and evidence of this provided to Council.
If necessary a stormwater treatment device designed and installed in accordance with the Auckland Regional Council Technical Publication 10 Design Guidelines for Stormwater Treatment Devices or other accepted design procedures may be necessary until the upstream catchment road works have stabilised.

DS-4.9.3 Urban Roadside Barriers and Guardrail Design

The following shall apply:

NZTA Road and Traffic Standards RTS 11 – Urban Roadside Barriers and Alternative Treatments shall be the basis for urban guardrail design.
Guardrails shall be designed by an experienced Chartered Professional Engineer in accordance with the current NZTA Specification M23 and the current State Highway Geometric Design Manual. The end assembly shall comply with NZHRP 350 TL-3 unless specifically approved by the Council.
Where roads, private ways or other vehicular or pedestrian access, whether public or private, run parallel with land which drops on one or both sides, the sides shall be provided with safety barriers to protect pedestrian or vehicular traffic.
Safety barriers for pedestrian access shall comply with the design requirements of the Approved Document D1 of the New Zealand Building Code as referred to in NZS 4404.
All signage shall comply with the Traffic Control Devices Rule 54002.

DS-4.9.4 Streetscaping

Refer to:

DS-2 Streetscape.

DS-4.9.5 Streetlighting and Traffic Signals

The following shall apply:

The design of traffic signals for local roads shall follow the requirements of the Council Traffic Systems Design and Implementation Guidelines. Where not specified a recognised design standard and/or design method approved by Council shall be utilised.
For traffic signals on state highways, discussion shall be held with NZTA and their requirements met.