Case Studies Project Archives
Archive No. 2
Problem. This high-rise office tower near circular quay in Sydney was in danger of losing some of its facade cladding due to the failure of the original fixing system.
Solution. The DryFix thin panel pinning system was chosen as the simplest, most reliable and economical method for securing the cladding to the substrate. To minimize noise and inconvenience to the occupants, small pilot holes were drilled, at an angle, outside office hours, through the cladding and into the substrate. several thousand short DryFix pins were able to be power-driven into position during normal work hours, however, due to their easy installation.
Problem. Cracks developed in the masonry of this apartment block in Bellevue Hill as a result of brick growth and a lack of movement joints in the outer wall.
Solution. The repair detail for the building required the installation of expansion joints at several locations around its external wall. Having checked the security of the connection between the external and internal walls, 20mm wide vertical slots were cut through the external facing to create the movement joints. At regular intervals across the slots, mortar beds were cut out and the sections of wall tied together using short lengths of 6mm HeliBar. These were bonded into the mortar beds with one end of each bar being encased in a plastic sleeve to allow movement. The expansion joints were then filled with a fexible sealant and the slots rendered over.
Residential Apartment Block, Randwick, NSW
DryFix Applications
2005 | Top
Problem. Corrosion in the mortar beds of the original galvanised wire wall ties in this 1940's red brick apartment block in Randwick resulted in the bowing and near collapse of the building's outer masonry leaves.
Solution. The quickest and most cost-effective means of replacing the wall ties and preventing serious structural collapse was to install stainless steel DryFix remedial wall ties. Using the Helifix Power Driver attachment fitted to a light-weight SDS hammer drill, the DryFix ties were driven into position on all elevations of the building, via small pilot holes, to provide a secure and reliable mechanical connection between the cavity walls.
Problem. The large basement storage rooms in the south-east corner tower in the Natural History Museum, London, were suffering from various failed arches, cracking in the walls and ceiling and a cross wall separated from the external wall. These all possibly resulted from the foundations being affected by a number of recent dry English summers combined with the loadings on the vaulted arch brickwork from the ground floor display areas above.
Solution. To reinstate the failed arches HeliBars were bonded into the soffit masonry above the arches and tied into spandrel brickwork to spread the loads. Long series CemTies were then installed, in pre-drilled clearance holes, through the ring brickwork and into the masonry above and the cracks injected with cementitious grout. The cracks in the walls and ceiling were raked out and stitched with HeliBars and the cracks injected with CrackBond epoxy resin. The cross wall was reconnected to the external wall using 2m-long grouted CemTies. These concealed, non-disruptive repairs provided the most effective form of repair without having to introduce any other structural elements.
Problem. Built by convict labour in the1880's, St George's Cathedral in the heart of Perth, WA, was the subject of an extensive restoration project. The building suffered from cracking, movement and structural damage, much of it a result of the 1960's earthquake, which affected many of the city's original buildings.
Solution. HeliBar reinforcement and CemTies were installed to stabilise the masonry arches and structure of the building. Long clearance holes were drilled through the arch brickwork and into the masonry above. CemTies were then installed to secure the arches. Helibars, installed into the masonry above the arches and around the cathedral's many magnificent windows were used to provide horizontal restraint and distribute structural loads. After re-pointing and the removal of intermediary bracing, little evidence of the presence of Helifix CemTies and HeliBars remains.
Prince Henry Hospital, Little Bay, NSW
2005 | Top
Problem. The Prince Henry Hospital at Little Bay, NSW, was closed down in 1990. The 84-hectare site is now part of a large development. The site is being transformed into a residential area that will ultimately comprise of over 400 homes, apartments, shops and offices. The early stages of the project involved restoring and repairing many of the original buildings on the site which were suffering from wall tie corrosion and cracking.
Solution. Several thousand DryFix remedial wall ties were used to retie the walls of the existing buildings, while the Helibeam system was used to provide structural stabilility to unstable walls.
Problem and Solution. Once decribed as "the finest Roller Skating Rink in the Colony", the Trocadero in Newtown, NSW, opened in 1889. Now owned by the Anglican Church, the building, which has for some time been left in a state of disrepair, was recently the subject of significant preservation works. The works included Helifix crack stitching and reinforcement to parts of the building to repair and stabilise some of the more severely affected areas of the brickwork from cracking and movement, particularly around the arches and weak points throughout the structure.
Problem. This historical masonry aqueduct had developed a number of large cracks due to foundation settlement and the corrosion of structural steel components within the masonry.
Solution. CemTies were installed to cross stitch cracks, and stabilise and retie the brickwork. The corroded steel was removed to prevent further expansion and masonry cracking.
Residential Apartments, Norfolk, UK
Helibeam, Crack Stitching and BowTie Applications
HeliNews UK 2006 | Top
References: Helibeam, Crack Stitching and BowTie
Problem. This three-storey, brick built, Victorian semi-detached property was suffering from severe cracking to the front elevation after its drains had failed and caused subsidence below the front corner of the building.
Solution. After the drains had been repaired, the Helibeam System was installed to restore full structural integrity to the building. Pairs of HeliBars were bonded with HeliBond grout into channelled-out mortar beds at three levels, two between the ground and first floor windows and one above the first floor window. These HeliBars, running the complete width of the front elevation and the entire length of the return wall, formed masonry beams to distribute the loads, provide horizontal restraint and tie the brickwork together.
To stitch the crack next to the upper-storey window, single HeliBars were installed at five levels and returned half a metre around the corner. To provide lateral restraint, BowTies were driven into the floor joist ends between the two storeys and BowTies into the sides of the ceiling joists. After repairing the crack itself and making good, little evidence of the concealed repairs remains.
Problem. The corrosion and failure of the original ties in the Manning Building at Monash University resulted in the dangerous bowing of the outer walls.
Solution. The quickest and most cost-effective means of replacing the wall ties and preventing serious structural collapse was to install stainless steel ResiTies. Clearance holes were driven through the brick face and into the concrete backing material. Resin was then injected into the holes in the concrete. The ResiTies were then pushed into position and the outer holes filled with resin to provide a secure and durable connection.
