Big Culvert

INFRAPIPE makes the biggest culverts in New Zealand (up to 3.2 metres in diameter) and the second biggest in the Southern Hemisphere (3.5metres). It uses the KRAH helical wound machine to produce pipes with an effective length of 5.8m (total length 6m) with an SN rating from 2 to 40+.

An HDPE stormwater pipe has the best asset life – and Whole Life Cost – for the following reasons:

These studies and meta-study confirm the life of HDPE as 100+ years.

Many culverts are just plain tubes, but for a growing number of applications the pipe is the backbone but not the entirety of a stormwater management system. For full details read this document   because INFRAPIPE can incorporate any of the elements shown below:

And do so quickly, effectively and economically – and INFRAPIPE will even handle the design for you. Submit the plan and they can return a file with what connections need to be done where, because there are less connections with INFRAPIPE!

It is impossible to overstate the value of ease of installation for culvert projects. Here are some of the reasons that time is of the essence:

• Less time = less water – from the ground, the sky or the existing channel.
• Less digger time = less diesel, less servicing.
• Less staff time = less costs.
• Less P & G and site costs.
• Less time on site = less problems!

Why is INFRAPIPE the easiest solution to install:

• Pipes come in 5.8m or 11.8m lengths – joins reduced by 58%.
• Pipes fit easily – they are machined to fit.
• Pipes are six times lighter than concrete so they are easy to manoeuvre and easy to join.

A 600mm class 2 concrete pipe has an effective length of 2440mm and a weight of 663kg.

An SN4 INFRAPIPE has an effective length of 5800mm and a weight of 97kg.

Weight per metre – INFRAPIPE 16.7kg Concrete 271 kg

Bends and other modifications

HDPE is easy to cut, easy to weld and completely sealed and homogenous once modified. This enables the designer to accommodate a range of functions such as:

• Angled entry so that an inflow can be received
• Vertical bends so that flow can be further directed once on the lower side of an embankment or hill, moving the outflow away from the critical areas.
• Horizontal bends to take the most appropriate route
• Horizontal bends to improve the converging angle of connections and maximise hydraulic efficiency

Therefore – culverts do not need to be straight!

Traditional stormwater design, driven by the constraints of concrete, relies on manholes for changes of direction and draws straight lines between them. INFRAPIPE KRAH culverts can easily add bends of any angle at any point to allow culverts to follow the lie of the land, skirt around obstacles or other services and take the most economical path. This has the following benefits:

• Less pipe length.
  • • Therefore less excavation.
• Less pipe depth (and hence strength).
  • • Therefore less excavation.
• Less manholes.
  • • Therefore less excavation.
• Less work on connections.
• Smaller site footprint, easier access.
• Less remediation.

Environmental protection

INFRAPIPE can incorporate fish baffles or ladders or any other protections required for the flora and fauna of New Zealand. In addition, scour blocks or surge protectors can also be fitted in the factory or onsite.

A 10mm concrete pipe abrades at 0.7mm/100kcycles. For an 8mm inner layer INFRAPIPE, the abrasion is 0.2mm/100kcycles. The life of the concrete therefore is 14,280 kcycles, the life of the INGFRAPIPE is 40,000 kcycles.

The Darmstadt procedure, which has been the standard for abrasion testing since the 1960s, simulates the abrasion and resulting wear of liners and pipes that would occur in actual operating conditions by tilting a pipe section containing a mix of sand, gravel and water through 22.5degrees above and below the horizontal for at least 100,000 cycles. The results for PP or PE pipe show a greater resistance to abrasion and hence operating life.