Quick Enquiry Call Us

Search

If you cant find what you’re after please don’t hesitate to contact us.

Select Region

Please select the global region website you'd like to view.

Asia
Japan

Quick Enquiry

Submit your enquiry using our online form and include a brief message about the type of issues you are experiencing. One of the Mainmark experts will contact you as soon as possible.

Hidden
This field is for validation purposes and should be left unchanged.

Project Profile N19A006

Teretek® Remediates Sydney Harbour Seawall

Sub-industry
Seawalls
Problems
Erosion
Location
NSW
Year
2010
Solutions
Void Filling
Technology
Teretek®

The problem

An 18.5m long historic sandstone seawall protecting a waterfront apartment on Sydney Harbour had started to deteriorate. The seawall is situated on one of Australia’s busiest waterways, opposite the Sydney Opera House and Harbour Bridge, and is subjected to continuous water movement from all types of ocean vessels including ferries, ocean liners, boats and leisure crafts. Strong southerly winds, choppy waters, and tidal currents had impacted the wall, causing a substantial amount of erosion including a washout of fines between the seawall’s joints. Large cavities were identified along the seawall, with the worst affected areas at the highest and lowest tidal levels. The suction effect due to the tidal currents had also caused voids to form behind the wall, leading to the partial subsidence of a patio area facing the water’s edge. A complete restoration of the heritage wall, which dates back to the 1890s, was planned including repointing of the sandstone. However, before the work could commence, the seawall needed to be stabilised and the patio area re-supported. The seawall’s restoration contractor engaged Mainmark to provide a structural solution to fill the voids behind the sandstone blocks, re-support the seawall, and lift and relevel the patio area so it could be safely utilised by residents.

The solution

A solution that could withstand the harsh harbour environment was required to re-support the seawall, seal the gaps in the sandstone joints and fill voids behind the wall. The solution also needed to consolidate the ground beneath the sunken patio and return the area back to level. Due to the tides, a fast-acting and easy-to-apply solution with a fast cure time was needed. It was also critical that the solution had zero impact on the environment and did not pollute the harbour. Given the seawall’s location and heritage significance, the solution needed to comply with a 50-year design life..

The Result

Mainmark recommended Teretek® resin injection solution to remediate the seawall and re-level the patio. Teretek is an engineered polyurethane resin mix that, when injected into the ground, expands by chemical reaction which strengthens the ground and fills voids. Despite the seawall’s fragile state, Mainmark technicians were able to carefully inject the Teretek solution into the affected areas, which were between 2m and 3m below the edge of the patio terrace. A floating boom was placed into the water surrounding the wall to collect any waste, which could then be easily retrieved and removed without causing pollution. The contractors considered the inert Teretek® engineered resin a very safe and suitable solution compared to alternative cementitious materials that would have dissipated in the water. Teretek®’s easy application method and fast curing time enabled the team to complete the injection process within the very short window of time during low tide. Remediation of the 1.5m wide x 2.5m deep section of the seawall was successfully completed in one shift without the need to demolish, excavate, or rebuild the seawall. This was completed on a difficult access site by parking the Mainmark Rig at street level and injecting the resin via 80m hoses. Teretek resin is backed by a 50-year product warranty, which met the contractor’s requirement that the solution should comply with a 50-year lifespan, ensuring the heritage seawall will remain in place well into the future.

Resources

Project Resources & Downloads

Teretek® Remediates Sydney Harbour Seawall
Teretek®
Next Project

Bespoke Culvert Relining Delivers Engineered Solution for Major Infrastructure Project

Mainmark

© 2024 The Mainmark group of companies. ‘Mainmark®’, ‘Terefil®’, ‘Terefirm®’ and ‘Teretek®’ are trademarks of the Mainmark group of companies.

Mainmark Ground Engineering Pty Ltd
ABN: 51 606 182 503

ISO 9001
ISO 14001
ISO 45001

Residential

Commercial

Infrastructure

Mining

About Mainmark

Our team

Careers

Contact

Technologies

Media & Press

News

Awards

Privacy Policy

Terms and Conditions

Created by Codex

YouTube
Facebook
LinkedIn
Instagram