RESTORATION AND UPGRADE OF THE ORIGINAL CARPARK STRUCTURE
Owned by QIC (Queensland Investment Corporation) Westpoint Blacktown is a large shopping centre situated in Western Sydney. It was first opened in 1973, and then refurbished and expanded in 2006, making it one of the biggest shopping centres in Sydney.
MPN undertook the challenging restoration and upgrade of the original carpark structure at Westpoint Blacktown. The two original car parking blocks built in the early 1970’s were approaching the end of their design life with signs of deterioration, so investigations were carried out into their structural integrity. MPN undertook a structural assessment of the building which included extensive site surveys and inspections, in-depth desktop reviews of available documentation and a longevity study (with the aid of Mahaffey Associates). Rigorous investigations included concrete core samples and pulse echo ultrasound to ascertain concrete strengths, carbonation testing, exposing existing reinforcement to verify details and corrosion levels, geotechnical testing of founding materials, weld testing of existing steel connection samples and the examination for the presence of sufficient grout within every post-tensioned duct. The results of this exhaustive effort to ascertain the integrity and capacity of the structure justified the subsequent comprehensive upgrade project to give this structure another life.
KEY PROJECT DETAILS
MPN successfully undertook the design and inspections of the following rectification works:
- Column strengthening of slender blade columns with in-built sliding “v” joints, with minimal disruption to car parking layouts
- Grouting of unbonded PT tendons/ducts
- Installation of over 1200 steel beams to increase slab capacity
- Installation of shear walls for lateral earthquake bracing with minimal disruption to car parking layouts
- Structural steel strengthening of perimeter vehicle barriers
- Injection/pressure grouting of flexural slab cracks
- Reinforcement corrosion treatment and grout patching of spalling concrete
- Application of epoxy Waterproof membrane to exposed slab surfaces to reduce water ingress and corrosion
- Application of new Acrylic coating to slab soffits to prevent further carbonation where concrete cover was non-compliant
- Upgrades to existing and design of new plant and mechanical rooms to improve ventilation and remove exhaust fumes
- Structural transfer of 5 carpark levels over an existing/live substation