Steel Multi-plate Structures

Corrugated galvanised steel culverts have been used around the world for well over 100 years and are a proven option for typical civil infrastructure applications. Steel Multi-plate is a cost-efficient culvert offering up to 50-year design life in low corrosion environments in New Zealand.

For more information on the durability, performance and methods for predicting the service life of CSP's range of Multi-plate structures click here.

For more demanding applications CSP also offers products with extended service life - Aluminium Multi-plate (75 years) and Multi-plate 100+ (100 years). Steel Multi-plate culverts can span up to 8m (depending on the loading and backfill). For spans exceeding 8m refer to CSP's SuperCor™ information.

Application Versatility

The versatility of Multi-plate structures is limited only by engineering inventiveness. Traditional uses include culverts - small and large, bridges, storm drains, pedestrian and stock underpasses. However, other applications include mine and tunnel portal protection, conveyor housings, water tanks, caissons, underground storage facilities, and even wineries.


Cost Benefits

Steel Multi-plate installation can provide many advantages:

  • Cost-efficient and convenient culvert option offering service life of up to 50 years
  • Culverts are designed by Project Engineers, however, CSP can review the structural design and issue Producer Statement PS2 (Design Review).
  • Fast economical job completion.
  • Simple assembly – please note the project requires engineering supervision and the backfilling of the structure requires skill and experience.
  • Low equipment costs for assembly due to lightweight of average plate, i.e. less than 150kg.
  • Pre-assembly reduces inconvenience and cost to maintain existing services.Ease of Installation

Easy installation

Easy installation of Steel Multi-plate culverts offers very real benefits to specifiers in both normal and difficult situations. The easily handled corrugated plate system can be erected on-site - an ideal solution for remote areas where access is difficult - or delivered to site fully assembled if access and transport regulations allow, where fast job completion is vital.

Multi-plate structures derive their strength through interaction of the surrounding backfill. Design and supervision of this should be conducted by an experienced engineer. The site engineer is to ensure that assumptions made at the design stage are present on-site and that backfilling is in accordance with the specification.

Note: Multi-plate structures are not stocked items. A lead time for manufacture can be provided following the design and consultation process.


Design, manufacture and Installation requirements for Steel Multi-plate structures are specified in AS/NZS 2041: Buried Corrugated Metal structures. This is a joint Australian and New Zealand Standard and has several parts. Those applicable to Steel Multi-plate are as follows:

  • AS/NZS 2041.1:2011 Buried Corrugated Metal Structures - Part 1 Design Methods
  • AS/NZS 2041.2:2011 Buried Corrugated Metal Structures - Part 2 Installation Methods
  • AS/NZS 2041.6:2011 Buried Corrugated Metal Structures - Part 6 Bolted Plate Structures