Case Studies Project Archive
Crack Stitching Application
Problem. The old Goodlet and Smith Brickworks, a thriving and well-known brick manufacturing operation during the late 1800's, was to be restored and converted to become the centrepiece of a modern residential development comprising over 300 new mixed residential dwellings. However, the tall brick chimney stacks were unstable and potentially dangerous due to extensive vertical cracking, the likely result of past lightning strikes.
Solution. With minimal disturbance to the original building fabric, HeliBar stainless steel reinforcing bars were installed to stitch the cracked masonry. After chasing out the appropriate mortar beds the HeliBars were bonded into position to provide a secure and reliable solution, stabilize the stacks and spread structural loads to help prevent any future cracking.
Problem and Solution. Some years ago, St Brigid's church in Coogee, NSW, underwent its first major restoration since its construction in 1921. A striking building with brick decoration in Byzantine style, St Brigid's is heritage listed but has suffered from the coastal salt spray and vibrations from pounding surf and low flying aircraft which have caused extensive deterioration of the masonry.
As part of the A$1m refurbishment a combination of DryFix and ResiTies were installed to secure the prominent tower. Constructed from multiple brick skins, the bell tower is 570mm thick at ground level and steps down to 230mm at level six and 110mm at the top level. The wall ties had either failed through corrosion or did not extend the width of the walls. The new stainless steel Helifix ties,ranging in length from 180mm to 520mm, were installed through to the innermost skin to stabilise the tower and, with extensive repointing, full structural integrity was restored.
Problem. During a refurbishment programme, over 20 residential blocks of three and four storeys, belonging to the Department of Housing, were discovered to be suffering from wall tie failure due to the corrosion of the original galvanized wire ties.
Solution. DryFix remedial wall ties were the obvious replacement ties to be used. They not only provided an economical solution to the problem of the failed ties but as they could be rapidly and efficiently installed during a short contract period the contractor was able to utilize the same scaffolding as the window replacement company to provide further overall savings.
Problem. As part of the Sydney Aircraft Noise Insulation Project (S.A.N.I.P.), a large number of buildings, including schools, churches, nursing homes and private houses, have been furnished with sound reducing insulation in their roofs and walls. During the installation of these materials many of the buildings were also found to be suffering from wall tie corrosion.
Solution. In order to secure the masonry of buildings at risk and to ensure that the new additional loads did not aggravate the problem, a number of the buildings underwent wall tie replacement programmes using either DryFix or RetroTie remedial wall ties depending on the construction materials.
Problem. A heritage listed hi-rise office tower in Sydney was in danger of losing some of its marble facade cladding due to the failure of the original fixing system.
Solution. The DryFix system was used to secure the 25mm thick marble panels to the substrate. Outside office hours, to minimize noise to the building occupants, small (6.5mm diameter) pilot holes were drilled, at an angle, through the marble and into the substrate. Due to their rapid and quiet installation, the DryFix pins themselves were able to be power-driven into position during normal work hours and were automatically countersunk below the face of the marble. After sealing and making good there was virtually no sign of the work that had been carried out.
Problem. The Sydney Opera House was the subject of a major rerfurbishment project prior to the 2000 Sydney Olympic games. During the refurbishment project, contractors discovered that, due to corrosion, many of the structural piers that support the concrete panels that comprise the opera house forecourt required the installation of new concrete caps and the problem of how to secure these new caps came to the fore. Of concern to the project engineers and contractors was the need to find a means of fixing these new caps in such a way that they could accommodate the two tonnes of load that would ultimately be exerted upon them.
Solution. Following extensive trials, DryFix ties were chosen because of their strong mechanical fixing properties and because they are made from marine grade 316 stainless steel. Consequently their long term performance was more certain than other fixing methods that were considered. The speed and simplicity of DryFix installation was seen as an added bonus by the contractors responsible for their installation.