Heavy rain in Tbilisi and Batumi regularly shows how many storm collectors are undersized. When a new district, highway or industrial park needs a stormwater collector or culvert above DN 1000, designers have traditionally chosen reinforced concrete or corrugated steel. Today, large-diameter HDPE corrugated pipe is often the faster, lighter and longer-lasting option. This article explains when large-diameter corrugated pipe makes sense and how to specify it.
What is structured-wall HDPE pipe?
HDPE corrugated pipe has a smooth inner wall for good flow and a ribbed or corrugated outer wall for ring stiffness. It is made to EN 13476-3 in stiffness classes SN4, SN8 and SN12. The pipe is light, and most of its strength comes from the soil around it: correctly backfilled, the pipe and soil work together as one structure.
GON's large-diameter range covers:
| Parameter | Range |
|---|---|
| Diameter | 100 – 3000 mm |
| Wall thickness | 1.3 – 14 mm |
| Length | 6 m |
| Ring stiffness | SN4 – SN12 |
| Standard | TS EN 13476-3:2018+A1 |
Locally made corrugated pipe generally goes up to about DN 1600. For collectors from DN 1800 to DN 3000, GON's range covers the sizes that are hard to source in Georgia.
HDPE vs concrete vs steel at large diameters
| Criterion | HDPE corrugated | Reinforced concrete | Corrugated steel |
|---|---|---|---|
| Weight (DN 2000, per 6 m) | Light – small crane or excavator | Very heavy – large crane | Medium |
| Joints | Couplings with rubber seals, watertight | Mortar or rubber joints; leak risk | Bolted bands |
| Corrosion / H₂S | Fully resistant | Attacked by sewer gas | Needs coating |
| Abrasion (gravel, sand) | Excellent | Good | Moderate |
| Installation speed | Fast, short sections | Slow | Medium |
| Service life | 50–100 years | 50+ years | 25–50 years |
For storm collectors that carry sand and stones from hillside streets, HDPE's abrasion resistance and smooth bore are clear advantages.
Specifying the stiffness class
- SN4 – green areas, low cover, no traffic.
- SN8 – the standard choice under roads and parking with normal cover depth.
- SN12 – deep trenches, heavy traffic, poor native soil or shallow cover under highways.
Your structural designer should confirm the class with a ring-deflection check (usually below 6% long-term) based on cover depth, traffic load and soil type.
Typical applications
- Storm collectors for new residential districts and boulevards
- Road and highway culverts
- Retention and attenuation tanks made from large pipe sections
- Relining old concrete or masonry collectors (slip-lining)
- Irrigation and melioration channels in enclosed pipe
What to write in the BOQ
*"Structured-wall HDPE corrugated pipe to EN 13476-3, DN/ID 2000, SN 8, 6 m lengths, with couplings and EPDM seals; laid on 150 mm granular bedding with granular surround compacted to 95% Standard Proctor to 300 mm above crown; long-term deflection ≤ 6%."* State the SN class for each section, as cover depth and traffic change along the route.
Quick selector
- District storm main DN 1200 under a road, 2–4 m cover → SN8.
- Highway culvert DN 2000, 1 m cover, heavy traffic → SN12 + well-compacted granular surround.
- Park drainage collector DN 1000, no traffic → SN4.
GON project experience
GON supplies corrugated HDPE pipe and has delivered manholes and rain gratings for Tbilisi road works on Akaki Tsereteli Avenue, Tskneti Highway, Kakheti Highway and 9 April Street. Combining pipe, manholes and gratings from one supplier simplifies storm-network packages for contractors.
Related products: HDPE corrugated pipes · Cast-iron manholes · Rain gullies & gratings · Concrete collectors
Further reading: Corrugated HDPE: SN 4, SN 8 or SN 12?
Can HDPE pipe carry sewage as well as stormwater?
Yes. EN 13476 pipes are designed for non-pressure drainage and sewerage, and HDPE is resistant to sewer gases.
How are large-diameter pipes joined?
With couplings and EPDM seals, or by extrusion welding for special connections and manholes.
What lead time should we plan?
The very largest diameters may be supplied to order rather than from stock. Share your schedule early and GON will confirm availability and the delivery window.
Get a project quote
Send your storm-network drawings or BOQ to sales@gon.ge or call +995 595 818 800. GON delivers to projects in Tbilisi, Batumi and across Georgia.
GON supplies drainage, water, gas and road-infrastructure products to contractors, utilities and IFI-funded programmes across Georgia.