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Assessing Structural Integrity: Pitt Street Hotel

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Assessing Structural Integrity: The 372-382A Pitt Street Hotel Redevelopment

In the heart of Sydney, redevelopment projects blend heritage preservation with modern innovation. Well Smart Group engaged BCRC Durability Consultants to assess the structural conditions at 372-382A Pitt Street, an ambitious project involving significant redevelopment while retaining a historic façade.

Project Scope and Purpose

The redevelopment includes the construction of a new 60-storey hotel tower with a 4-storey mixed-use podium. BCRC’s inspection focused on the structural integrity of the retained front 6 metres of the existing buildings, including the façade. Comprehensive site assessments were conducted using a combination of advanced non-destructive (NDT) and destructive testing methods.

Key Inspection Methods

BCRC’s thorough assessment employed:

  1. Visual and thermal imaging inspections
  2. Ground Penetrating Radar (GPR) for concrete cover and reinforcement detection
  3. Core sampling for compressive strength and chemical analyses
  4. Masonry tests, including compressive strength, mortar scratch tests, and bond wrench tests
  5. Foundation assessments through visual inspection and coring

Enhanced Structural Condition Assessment and Targeted Remediation Measures

Façade and Masonry Walls
The façade demonstrates overall structural soundness, constructed using traditional staggered brick bonding. While the absence of modern cavity ties presents an opportunity for moisture control improvements, the structure remains fundamentally intact.
To ensure optimal long-term performance, the following enhancements are being implemented:

·       Façade Upgrades: Immediate repair works include sealing of cracks, selective brick replacement, and the application of advanced waterproofing solutions to prevent moisture ingress.

·       Masonry Wall Rehabilitation: Despite adequate compressive strength, areas exhibiting cracked bricks and deteriorated mortar joints are undergoing repointing and localised brick replacement, reinforcing both strength and appearance.

Concrete Slabs
The concrete slabs exhibit adequate structural capacity, indicating sound original construction.
In order to maximise service life and mitigate isolated issues, the following steps are underway:

·       Contamination Control: Localised remediation is being conducted on the affected unit to address potential contamination.

·       Corrosion Prevention: With chloride and carbonation levels found to be low, corrosion risk is currently minimal; however, monitoring systems are being introduced to ensure early detection of any future changes.

·       Structural Reinforcement Planning: A load-bearing capacity assessment has been conducted to identify potential issues and rectify them.

Foundations
The existing continuous strip footings beneath the retained sections were found to be stable and performing well. Minor cracking has been noted and will be monitored as part of ongoing maintenance, ensuring early intervention if required.

Ongoing Recommendations and Durability Strategy
To support continued structural integrity and long-term resilience, BCRC has developed a proactive remediation and maintenance strategy that includes:

·       Prompt façade and masonry repairs to improve moisture resistance and visual integrity.

·       Localised concrete remediation in the affected unit to eliminate contamination risks.

·       Continued condition monitoring across all critical structural elements throughout the redevelopment phase, ensuring adaptive management of the asset’s condition.

Future Outlook

By proactively addressing these recommendations, the 372- 382A Pitt Street redevelopment will successfully integrate historical architecture with contemporary construction practices. Ensuring structural durability remains paramount for the success of this iconic project.

For expert advice on durability and structural assessment, contact BCRC Durability Consultants today.

Assessing Structural Integrity

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Safeguarding a Sydney Icon: Darling Harbour Structural Investigation

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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.

Structural Investigation Darling Harbour Promenade

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Ensuring Structural Integrity: Narrabri Bridge Inspection Project

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Ensuring Structural Integrity: Narrabri Bridge Inspection Project

Bridges form a vital part of our transport network, and maintaining their structural health is crucial for public safety and infrastructure longevity. BCRC Durability Consultants recently conducted an extensive inspection on the Narrabri Bridge, located on the Newell Highway (HW17) in Narrabri, NSW, at the request of Transport for NSW (TfNSW).

Here’s an insight into the project, its findings, and recommended actions.

Project Overview – Narribri Bridge

The Narrabri Bridge comprises multiple sections constructed at different times, with our investigation focused on the western end completed in 1977. Now 47 years old, this reinforced concrete beam bridge spans Narrabri Creek, supported by prestressed girders on eight piers.

BCRC’s inspections targeted 4No. piers, utilising advanced non-destructive testing (NDT) techniques to identify potential defects without causing harm to the structure.

Advanced Inspection Techniques

To ensure a thorough understanding of the bridge’s condition, our team employed multiple NDT methods, including:

  1. Ground-Penetrating Radar (GPR): To detect reinforcement positions and internal
  2. Ultrasonic Pulse Echo (UPE) and Ultrasonic Pulse Velocity (UPV): To identify voids and cracks and assess concrete quality.
  3. Impact Echo (IE): To detect flaws or defects within the
  4. Rebound Hammer Testing: To evaluate surface hardness and estimate compressive

Structural Assessment Summary and Remediation Plan

The detailed structural investigation of 3No. Piers confirmed their excellent condition, with no significant internal defects or signs of concrete deterioration. These piers demonstrate reliable material performance and structural soundness, affirming the effectiveness of the original construction.

Targeted Remediation Strategy for the Fourth Pier Based on Advanced Diagnostic Techniques

The fourth pier was subject to a comprehensive assessment utilising both visual inspections and advanced non-destructive testing (NDT) methodologies. This integrated investigative approach proved highly effective in guiding a focused and informed remediation plan:

  1. Surface Condition Assessment and Treatment
    Visual inspections identified surface-level changes at the headstock and corbel faces, which provided early indicators for stress-related behaviour. These observations allowed for the timely application of specialised crack sealing techniques, effectively mitigating any risk of moisture ingress and maintaining the element’s long-term durability.
  2. Advanced Internal Diagnostics and Restoration
    NDT methods—including Ultrasonic Pulse Echo (UPE) and Impact Echo (IE)—were instrumental in detecting subtle internal variations near the girder connection zones. These findings informed the decision to conduct targeted core sampling, which validated the presence of isolated voids. As a result, precision pressure grouting (void injection) is being applied to restore internal continuity and enhance structural soundness.
  3. Material Performance Profiling and Strength Optimisation
    The core extraction process not only validated internal observations but also provided valuable compressive strength data. This enabled a tailored strength enhancement strategy, ensuring the pier’s capacity is brought in line with adjacent structures. The findings also support refinement of design assumptions for future asset maintenance and upgrades.

Proactive Structural Health Monitoring
Based on the detailed diagnostic outcomes, a long-term monitoring regime has been established. This includes scheduled inspections, condition tracking, and trend analysis, allowing for proactive maintenance and adaptive management of the pier’s condition over time.

Monitoring Structural Integrity for the Narribri Bridge

Through our comprehensive inspections and detailed analysis, we aim to help Transport for NSW ensure the continued safety and durability of the Narrabri Bridge. Regular monitoring, timely interventions, and advanced NDT methods will play critical roles in maintaining the structure’s longevity.

Get in touch with the BCRC team to learn more about bridge durability solutions or discuss similar projects.

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BCRC-Narribri-Bridge-structural-integrity
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Sydney Airport: Concrete Testing Insights

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Strengthening Sydney Airport: Concrete Testing Insights

Sydney Kingsford Smith Airport (SYD) is Australia’s busiest transportation hub. With thousands of aircraft movements daily, its three runways endure immense loads, making concrete durability a critical factor in long-term performance and safety.

To uphold stringent quality standards, BCRC Durability Engineers were engaged for expert inspection services to ensure the integrity of the Portland Cement Concrete (PCC) pavements used in runway construction.

Comprehensive Durability Testing & Assessment by BCRC

BCRC’s review focused on three key stages:

1. Preliminary Investigation & Specification Review – Assessing compliance with Australian Standards.

2. Concrete Test Analysis – Evaluating sampling and testing procedures.

3. Concrete Cylinder Testing Inspection – Verifying laboratory testing accuracy.

Stage 1: Preliminary Investigation & Specification Review

Before conducting field tests and laboratory inspections, BCRC comprehensively reviewed project specifications and testing methodologies. This foundational stage ensured that all durability assessments aligned with industry best practices.

Durability Assessment – Key Findings:

1. Compliance with Australian Standards and relevant specifications

a. A thorough review provided clarity on how project specifications can align with Australian Standards and best practices for PCC pavements.

2. Concrete Mix Performance

a. A detailed review of mix designs, including material composition and water-cement ratios, indicated that the expected performance met project requirements.

3. Comprehensive Concrete Strength Analysis

A detailed analysis of test results provided evaluation on compliance with Australian Standards and project specifications for both compressive and tensile strength, with strength projections indicating sustained performance over the long term.

4. Risk Assessment

a. Potential risks affecting workability, strength, and durability were identified and addressed to ensure consistent performance across placements.

5. Standardized Testing Methodologies

a. A structured testing framework was developed to ensure consistency in both field and laboratory evaluations.

This initial phase provided valuable insights to refine the methodology for subsequent testing stages.

  • Sydney Airport Concrete Testing
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Stage 2. Sydney Airport Pavement Testing & Analysis

BCRC independently evaluated concrete sampling and testing procedures at Sydney Airport. BCRC conducted a site visit to provide expert guidance on several key aspects of concrete placement, testing, and quality control.

The recommendations focused on ensuring consistency, workability, and compliance with Australian standards, with particular emphasis on the following:

1. Maintaining Concrete Workability and Consistency

BCRC advised on strategies to maintain uniformity in concrete workability throughout placement. This included monitoring mix variations between deliveries, adjusting water content within allowable limits, and using appropriate admixtures to enhance workability while preventing segregation or excessive bleeding.

2. Specimen Preparation and Compliance with Australian Standards

To ensure reliable and representative testing, BCRC provided guidance on casting test specimens in accordance with Australian standards.

This included best practices for filling and compacting molds, the appropriate use of a vibrating needle to improve compaction, and proper curing conditions to achieve accurate strength results.

3. Enhancing Concrete Workability and guaranteeing that the required compressive strength is achieved

Recommendations were made on optimising concrete handling and placement techniques to improve workability without compromising strength. BCRC also emphasised the importance of robust quality control measures, including routine slump testing, temperature monitoring, and adherence to project-specific requirements to ensure that the concrete achieves the required compressive strength.

Through these recommendations, BCRC aimed to enhance the overall quality and durability of the concrete, ensuring it meets both project specifications and industry best practices.

Stage 3: Concrete Cylinder Testing Inspection

In the next phase, BCRC assessed compressive strength testing of concrete cylinders at the Laboratory.

With over 80 concrete lots poured since July 2023, robust testing is essential to ensure long-term serviceability.

The concrete mix underwent rigorous evaluation to verify:

  • Specification compliance
  • Testing accuracy across site and laboratory conditions
  • Variations in methodologies impacting results
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Concrete Testing – Key Industry Recommendation: Adopt Internal Vibration for Cylinder Casting (AS 1012.2)

Why Internal Vibration Matters:

1. Reduces internal defects, improving concrete matrix integrity.

2. Ensures uniform compaction, leading to more reliable test results.

3. Enhances strength consistency, minimising discrepancies across labs.

Implementing internal vibration techniques can significantly improve the reliability of compressive strength testing, enhance quality assurance, and reduce testing inconsistencies across major infrastructure projects.

Commitment to Quality, Durability & Cost-efficient solutions

The compliance assessment of the runway bays ensured that the structure met Australian standards while also identifying cost-saving opportunities for the client.

BCRC helped optimise construction practices, providing confidence that the project adhered to regulatory requirements without unnecessary expenses.

BCRC is dedicated to supporting infrastructure partners with expert durability assessments, materials testing reviews, and engineering solutions to ensure high-performance concrete structures.