Safeguarding a Sydney Icon: Harbourside Promenade Structural Investigation

Darling Harbour, one of Sydney’s iconic locations, is undergoing transformation and modernisation. As part of this exciting journey, Mirvac engaged BCRC Durability Consultants to perform an extensive investigation of the Harbourside Promenade, ensuring the safety and longevity of this prominent waterfront structure.

Project Background – Darling Harbour Promenade

The Harbourside Promenade structure, constructed in the late 1980s, comprises steel piles, headstocks, edge beams, precast planks, and cast-in-situ reinforced slabs. Following the demolition of an existing arcade, Mirvac sought BCRC’s expertise to assess structural conditions and durability aspects critical for future redevelopment.

BCRC’s Comprehensive Inspection Approach

Our detailed structural assessment utilised cutting-edge methods:

1. Visual and Drummy Surveys: Identifying spalled concrete, corrosion, and structural
2. Ground Penetrating Radar (GPR): Measuring concrete cover and reinforcing steel
3. Half-Cell Potential Testing: Assessing the likelihood of active
4. Concrete Core Sampling and Laboratory Testing: Evaluating compressive strength, carbonation depth, and chloride ion ingress.
5. Corrosion Assessment of Steel Piles: Including Cathodic Protection

Major Findings and Remediation Measures

To enhance the long-term performance and structural integrity of the facility, several targeted remedial actions were successfully designed and implemented:

1. Concrete Rehabilitation: Deteriorated concrete areas, particularly those exhibiting spalling and exposed reinforcement at critical zones such as headstocks and slab edges, were comprehensively addressed. Damaged sections were carefully removed, cleaned, and repaired using durable repair mortars, restoring both structural function and protective cover.
2. Chloride Mitigation: In response to localised elevated chloride concentrations indicating potential durability concerns, especially in areas with reduced projected service life, a proactive approach was taken. Surface-applied corrosion inhibitors and chloride-resistant repair systems were introduced to extend the life expectancy of affected zones and mitigate future corrosion risks.
3. Steel Pile Protection: Significant progress was made in addressing steel pile corrosion, particularly at pile-headstock interfaces. Surface corrosion was removed, and protective coatings were applied. The design also incorporated provisions for long-term durability, including allowance for the future installation of cathodic protection systems where deemed necessary.
4. Seawall Stabilisation and Structural Review: Observed movement and cracking in sections of the seawall prompted a detailed structural engineering review. Remedial strengthening works were implemented, which included crack injection, joint reformation, and localised structural realignment, ensuring improved stability and reduced risk of further movement.

A Proactive Future

The Harbourside Promenade is poised to remain a cherished Sydney landmark through meticulous assessment and recommended interventions.

BCRC Durability Consultants remain committed to delivering solutions that ensure structural integrity and long-term durability for generations to come.

To explore durable structural solutions or discuss similar projects, reach out to BCRC today.