Chapter F9 Improvement of roads

F9.3 W/C 322: Replacement of bridges and structures

Definition: work category 322

Replacement of bridges and other structures

This work category provides for the upgrade or replacement of existing bridges and other road structures, including culverts having a cross-sectional area of 3.4 square metres or greater, where this is the main purpose of the work.

Examples of qualifying activities

Examples of qualifying activities include:

• replacing a structurally inadequate bridge
• replacing a bridge for non-structural reasons, such as inadequate width or waterway
• modifying an existing bridge to increase its structural capacity to a level higher than originally provided
• widening an existing bridge
• approach work estimated to cost less than $50,000
• replacing retaining structures, including sea walls, that support a road
• replacing tunnels
• sealing bridge approaches on unsealed roads, dependent on the following conditions:
  • the approach sealing is limited to a maximum distance of 50 metres from each abutment
  • the seal continues over the entire structure to ensure consistency of skid resistance.

In locations where sealing costs are high, some alternative to sealing should be considered. The use of pavement stabilisers may be used as an economic alternative to sealing and may be included in the cost of the work.

The cost of proposed replacement must be checked against the NZTA's policy on uneconomic roading facilities.

Reference: For detail on uneconomic roading facilities, see section F10.13.

Exclusion: work category 322

This work category excludes:

• the provision of a new bridge or other structure where no structure presently exists - these are funded under work category 323: new roads
• replacement of a cattle stop - this is funded under work category 215: structures component replacements.

Bridge standards

New or replacement bridges involving funding from the NZTA must conform to the design and loading requirements of Transit New Zealand's Bridge manual. The NZTA may approve a specific departure from these design standards in terms of its policy on uneconomic roading facilities.

Reference: For detail on uneconomic roading facilities, see section F10.13.

At an RCA's discretion, single-lane bridges on low traffic volume roads in remote areas may be designed for a live load equivalent to class I without overload provision.

Retaining structures

The cost of maintaining existing retaining structures as necessary for the operation, protection or support of a road is funded under the work category 114: structures maintenance.