Nuflow protects Fremantle’s history by repairing arch culvert pipes

The repaired culvert drain 

Fremantle is a prominent port city in Western Australia. Its harbour is an important piece of infrastructure, doubling as a longstanding historical site and one of the largest cargo ports in the state. When refurbishments were conducted on heritage-listed buildings within the port, Nuflow Western Australia (WA) was brought in to address the existing drain and ensure that any refurbishment work would not jeopardise the area’s historic buildings. 

Old infrastructure puts a stop to renovations 

Part of the project included refurbishing a building for commercial tenants. This engineering team was required to replace damaged sheet piling that reinforced the building against the nearby ocean. However, installing new sheet piling would inevitably cause vibrations that risked damaging a 36m 1100 x 900mm brick stormwater culvert drain, which ran underneath the building. 

Constructed from brick, the asset was suspected to date back to the late 1800s when the port was first established. A camera inspection revealed that the culvert drain was severely damaged, with huge cracks along its surface and even whole bricks missing. The engineering team suspected that it would not be able to withstand the level of intervention needed to install sheet piling without collapsing and causing irreversible damage to the heritage-listed building above. 

So, they had to pause their renovation plans and find someone to help them with the culvert drain repair. However, they soon realised that the shape of the asset would make this difficult. 

damaged culvert drain
The damages to the brick culvert drain.

Culvert drain’s unique shape calls for a unique solution

Most drainage culvert drains are round, so most reliners are only equipped for this standard shape. However, the culvert drain running beneath the soon-to-be-renovated building were arched. This required a solution beyond the typical process, making it difficult to find someone able to deliver a suitable outcome. 

Luckily, the engineering team were referred to Nuflow WA. When Nuflow WA’s head reliner Steve saw the camera inspection footage, he knew they had the means and expertise to address the problem. Soon, they were on site conducting inspections and identifying the most effective solution and process. 

It was quickly determined that Sumoline would be the best product thanks to its strength and ability to structurally repair damaged infrastructure. Even if the pipe completely collapsed, the Sumoline resin would remain and keep things structurally sound. With the drain’s level of deterioration, this was a real possibility the team needed to account for. An added bonus was the solution’s ability to cure underwater, which would be especially useful since the team would be working with the tide. Nuflow WA also needed to develop a custom liner to cater for the unique size and shape of the arch culvert drain. Once this was all quoted, constructed and approved, Nuflow WA was able to get started.

A chilly preparation 

After their own camera inspection, the Nuflow WA team decided the best way to tackle the culvert drain was 6m at a time. However, before the relining process could begin, the technicians needed to ‘wet out the liner.’ This involves putting the resin into the liner before it can be pulled into the drain and cured.

When this is done in the sun it exposes the resin to UV, speeding up the curing process. This means the team would have to work very quickly, making the process difficult due to the sheer size of liner. Their solution was to change the climate using a 40-foot refrigerated container. Inserting the liner in this chilled environment meant the team had up to 2.5 hours to finish the job, as opposed to a one-hour time frame in the sun. 

fridge int

preparing the bladder for the culvert drain
The team preps the bladder inside the refrigerated container.

An ocean-assisted installation 

Once the liner was ready, it was time to get it into the culvert drain. Since it was around 300kg, this was a demanding process that required a lot of manpower. Installing this meant manoeuvring the liner from the container to the manhole access point, suspending it down the manhole and then positioning it into the culvert drain itself. The small access point and weight of the liner made manoeuvring difficult, but thanks to the team’s expertise they were up to the task.

After nine days of hard work, the final stages of the reline were complete. In order to prevent water from making its way between the Nuflow reline and the old culvert drain, installers finished off the end with Nuflow’s smooth trowel. The final result was a fully restored and refurbished brick culvert drain asset. 

The repaired culvert drain 
Nuflow’s work leaves the asset better than new. 
Blog Post Image

Repaired culvert drain get renovation back in action 

Thanks to Nuflow’s alternative no-dig solutions, the project engineers avoided the extremely expensive task of decommissioning the culvert drain by filling it with concrete and diverting stormwater elsewhere. They were also glad to be back on schedule without needing to worry about compromising the infrastructure below. Likewise, the port and the water authority were pleased to have everything back in working order. 

[H2] Let us solve your complex culvert drain problems  

Nuflow has the skills and know-how to assist with any manner of pipe issues. Our skills and experience across the industry of relining mean that we’re able to adapt these innovative solutions to suit your unique scenario. Save yourself time and expenses, and reach out to us today.

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