Clean Coal Silos, Mount Thorley

The clean coal silos at Mount Thorley Warkworth near Singleton. Following a health check by Vinsi Engineers, Structial were engaged  to undertake minor repairs and re-coating of the twin silos that were subject of a major repair project back in 2007. Brendan Walsh, Structial GM,  was the project manager  back in 2007 and remembers it well as it was in June 2007 that the Pasher Bulker ran aground on Nobby’s Beach in Newcastle. The same storm caused major flooding of the compound around  the clean coal silos causing the site to be evacuated. Refuge was taken in the nearby Willows Café at Broke where burgers and beers helped our team ride out the storm.

Grain Silos, Burren Junction

Late in 2020 Structial despatched a crew to northern NSW’s wheat belt, to complete upgrade works on GrainCorp’s Burren Junction wheat silos. Situated 51km west of Wee Waa, the project provided plenty of logistics challenges, but the team proved to be up to the task as major concrete repairs were completed both inside and outside of the 25m high concrete silos. Replacement train loading chutes were fabricated and installed through newly formed openings. Post tensioning specialists VSL were engaged by Structial to supply and install post tensioned cables to the repaired structures.

Rill Tower Concrete Repairs, Centennial Coal

Structial’s Hunter Valley crew headed south in September to complete a shutdown project at Centennial Coal’s Springvale colliery just outside of Lithgow. With two teams working round the clock, major concrete repairs, using Bluey Australia HB55, were completed to the rill tower which, after almost 30 years of continuous operation, was definitely in need of some TLC. Continuous erosion of the concrete surfaces by the coal flowing through the tower had exposed areas of reinforcement which were then subject to further impact damage by the dozers working on the clean coal pad. Detailed planning and superb execution by the project team provided the right outcome. The job was finished on time and to the required standard with nil safety incidents. Great work HV team.

18-20 Newton St, Alexandria

THE PROBLEM
18-20 Newton Street Alexandria is a complex of 32 units situated on a former industrial site in the inner western suburbs of Sydney. Completed in 2001, the three buildings that comprise the development developed severe structural issues determined to be due to differential settlement between areas of the complex founded on deep piles and those areas at the perimeters of the complex that were founded on a combination of strip footings and ground beams. Additionally, the complex suffered water damage throughout, due to poorly executed waterproofing. Also, numerous general building defects existed, such as defective cavity flashing, drummy and cracked render and internal defects.

THE PROCESS
Owing to the need to stabilize the building prior to reinstating finishes, the process was managed in a strict sequence that allowed settlement times before loading the new piles. After the client’s consulting engineer had given the go-ahead, the piles were loaded, and jacking took place, to transfer the building load to the new substructure.
The reinstatement of external structures and finishes was then undertaken including reinstatement of the road, footpaths, nature strip and the reinstatement of the interior of the residential units.
The owners also took the opportunity to redesign the internal courtyard of the building to include a community garden and barbecue area for the enjoyment of the residents.

THE SOLUTION
To prevent further subsidence, a foundation solution consisting of 11m deep large diameter continuous flight augered piles was installed around the complex. Load was transferred to the piles via pile-caps and tie beams and the building’s exterior facade was reinstated.
In conjunction with the foundation works, the waterproofing deficiencies were rectified, and an internal works programme was completed including works to all the occupied units.

HVO – Workshop Slabs

THE PROBLEM
The Hunter Valley Operations vehicle maintenance workshop has serviced thousands on mining vehicles since its construction and has deteriorated significantly overtime.

It was identified from core samples that oils and other chemicals had leached through the cracks into the soil below and that the works would require more than just a new slab to be poured.

THE PROCESS
Structial began the process by installing sound barrier curtains in the middle of the workshop so that half of the facility could remain active during the works.

We demolished the existing slab using excavator mounted breakers and removed the contaminated soil below to make way for a new base. Additionally, the new slab was thicker and reinforced with steel rail line tracks to take the load of the vehicles ensuring the slab would last.

Whistler St Car Park, Manly

THE PROBLEM

Whistler St Car Park by Manly Beach was built in the early 1970’s and was constructed using a one-way ribbed slab system with perimeter concrete parapet upstands. The perimeter upstands were deemed to be non-compliant to the current design code and spalling concrete was also becoming a problem for the structure. A feature of ribbed slab construction is the ability to reduce the slab thickness.  In the case of Whistler St. Car Park, the slab thickness on the north and south elevations was in the order of just 100mm. A design solution was therefore required to enable new crash barriers to be secured to the structure in a manner that satisfied the requirements of AS1170.1 for Type F light vehicle loading.

THE PROCESS

Northern Beaches Council selected Structial for the project following a competitive tender process based on a design & construct approach. Structial won the tender and based their programme on completing the work in 3 main stages to enable the car park to remain largely in operation during the works. Each stage was completed using an external perimeter scaffold that was largely used to enclose the work areas whilst large concrete saws were used to cut off the existing parapet walls. During off-peak times the removed wall sections were transported down through the car park using a tele handler that loaded them onto waiting trucks. B Class overhead protective hoardings were used to safeguard the general public       at the north and south end of the car park.

Given the proximity of retail and food outlets to the car park, measures were taken to reduce the noise originating from the construction operations, local businesses were kept appraised of progress throughout the process.

THE SOLUTION

Due to the thin car park slabs a bespoke bracket system was designed and installed which increased the torsional strength of the slab edges that ran perpendicular to the beams. Given the difficulties in materials handling around this congested site it was also important to develop a system for securing the Rhino Stop crash barriers that could be man handled into position. A two-part bracket system was engineered and installed that overcame the structural limitations of the slab edges following concrete repairs and coating of the slab edges.

Structial worked with the crash barrier supplier, Safe Direction, to overcome various detailed design issues to complete the project successfully in a highly active car park environment. The car park, once decried by locals as being run down, is now compliant and has a new look and lease of life.

68 Village Drive, Breakfast Point

Hermitage Hill Apartments
The Hermitage Hill Apartments is a 9 level block with 2 levels of basement parking. The works consisted of

• Window and door waterproofing
• Level 9 weatherboard wall repairs
• Balcony waterproofing
• Brickwork crack repairs
• and other miscellaneous repairs

The Marbury 174 Goulburn Street, Surry Hills

THE PROBLEM
The Marbury building was constructed in 2005. It consists of a reinforced concrete framework and a single skin panel wall internal/external wall system with a largely glazed façade.
It has suffered water penetration problems since construction. Severe leaks, originating from the glazing system, the single skin panel wall construction method and ineffective waterproofing of the main roof and podium level have detracted from the owner’s amenity and enjoyment of this major city centre high rise.
As below shown below, water penetration into the fabric of the panel wall system has caused deterioration of the gypsum outer casing. Delamination and blistering has occurred allowing moisture transmission into occupied spaces as the dividing walls are continuous from the exterior to the interior of the units.

THE PROCESS
Key to many rectification projects on existing structures and buildings is the choice of access and materials handling equipment. This is particularly the case in busy city centre locations and, even more so, when the building is fully occupied.
We devised an access and materials handling plan that provided them with good access to all work faces but also addressed the owners concerns with regards to loss of amenity and views during a lengthy rectification process.The access method chosen was to place mast climbing platforms on the main elevations. An overhead protective hoarding then doubled as a materials storage and delivery point with a mechanical hoist being used for vertical movement of materials to the podium.

THE SOLUTION
The problems at The Marbury necessitated extensive works. A holistic approach was taken that involved the removal and replacement of all windows and sliding doors with high quality, well rated, glazing products, the removal of all tiling and renewal of all waterproofing membranes on the balconies and podium areas. Additionally, all externally exposed dividing walls and column faces were overclad with a fibre-cement ‘rain screen’ cladding system to prevent moisture transmission into occupied spaces.

Crown Apartments, 27 River Street, Mackay

THE PROBLEM
Severe water penetration problems caused many of the residential units in the Crown apartment building in Mackay, far North Queensland, to become uninhabitable.
Poor construction practices and inadequate materials choices combined with the high rainfall, tropical temperatures and exposed location caused almost complete failure of the building envelope from a waterproofing and weather proofing view point.
Additionally, the passive fire systems within the building were found to be non-compliant. The Owners were also keen to ‘re-launch’ the building in the local property market and so upgraded it’s appearance.

THE PROCESS
Given that many units were unoccupied, we were able to accommodate a large crew from interstate within the building. Additionally, low occupancy simplified access issues, and enabled them to commence internal works quickly once external weather proofing was completed.
A large scaffold structure was utilised to complete the cladding and glazing works, providing good and safe access to the large crew needed to complete such a major over-cladding and re-glazing exercise.

THE SOLUTION
The widespread and generic nature of the defects found, determined that nothing short of a complete refurbishment of the buildings façade would suffice to restore the building to a premier position in the Mackay residential unit market.
We entered into a design and construct contract with the owners to construct a new rain screen cladding and glazing system for the building. The cladding consisted of the Hardies Exotec system coupled with new cyclone rated aluminium windows by G James.

Barry’s Fill Point, Hunter Valley

THE PROBLEM
Due to shifting mine operations, the heavy water cart fill point, at Coal &Allied’s Hunter Valley operations had to be relocated. Suitable locations were limited. The new location had to be close to main haul routes to reduce travel times and ideally would be at an elevated location to maximize gravity feed to the trucks and reduce pumping costs.
As usual on active mine sites, the work had to be conducted without disturbance of the ongoing mining operations and, in accordance with the stringent safety requirements of the mining company.
The project needed to be completed within a tight timeframe on a site that is badly affected by extremes of weather.

THE PROCESS
It was decided the project would be completed on an open book cost plus arrangement. This enabled the engineering team to commence work early on a concept design and to ‘firm up’ the basic design as the works commenced.
Assisted by daily feedback as to costs incurred, the engineering team was able to manage the project budget and tailor the engineering solutions to suit the available budget.

THE SOLUTION
Rio Tinto’s Projects Group engineers devised a scheme whereby an elevated structure would be erected in a central location adjacent to the main haul road.
The construction method used was to stack gabion baskets as a confining structure that was then filled with stabilised fill materials. A substantial reinforced concrete slab was then poured on the top of the structure before the three water retaining tanks were lifted into position.