Resurrection of Christchurch Art Gallery wins international award Tuesday, 05 July 2016

The post-earthquake resurrection of Christchurch Art Gallery has won the International Project of the Year at the 2016 Ground Engineering Awards.

The project saw Mainmark re-support and re-level the 33,000 tonne gallery in 52 days, rectifying foundation damage caused by the 2010 and 2011 earthquakes in Christchurch, New Zealand.

The Christchurch Art Gallery was resurrected using Jet Grouting and JOG Computer Controlled Grouting to re-support and re-level the 6,500 square metre foundations, without requiring excavation or the occupants or exhibits to vacate.

During the seismic events of 2010 and 2011, Christchurch was struck by thousands of earthquakes including one with the highest peak ground accelerations ever recorded (2.2 g). The Art Gallery was badly damaged by the February 2011 earthquake and experienced 150 mm of differential settlement – up to 182 mm subsidence in some places.

In 2015, the Christchurch City Council embarked on plans to repair the foundation damage. The requirement was to raise and re-level the gallery, a large multi-storey, glass-fronted, concrete-framed building of heavy construction, with underground car-parking and plant rooms.

Mainmark prepared and strengthened the foundations, creating cementitious grouted subsoil columns by Jet Grouting. Re-levelling then followed, by incrementally injecting a proprietary cementitious grout using JOG Computer-Controlled Grouting technology to produce the controlled lifting pressures required.

JOG Computer-Controlled Grouting is a unique process of multi-point, cementitious levelling of large and complex structures by computer-controlled equipment.

A high pressure, low volume computer-controlled grout pump circulates cementitious grout to as many as 128 injection points. The grout is circulated to each injection point in the quantity required at the moment it is required. This way the structure is raised evenly and gradually without any undue stress on any part.

Where the site and project require it, grout monitors may be established. These are an automated robotic, station based wireless monitoring system, which monitor and report levels and inclination data from a complete network of points over the entire footprint of the building being levelled. Reporting is done constantly and in real time to fine tune the injection program. The cementitious re-levelling of huge and complex buildings is controlled to the millimetre and results are achieved in a short time.

The building was lifted with the art gallery staff in situ – only the basement carpark was not in use. A bespoke monitoring system was also developed to digitally visualise the building’s lifting movement in real time using data from measuring instruments throughout the building, allowing precise adjustments throughout the process.

Mainmark worked with the project’s engineering team to re-support and re-level the Gallery, restoring its design levels to +/- 10 mm across the entire foundation. Christchurch’s gallery is the largest building globally to be lifted and re-levelled to this extent, utilising innovative ground strengthening.

The Ground Engineering Awards celebrate engineering excellence with 15 award categories spanning innovation, project and stakeholder management, sustainability, health and safety and technical excellence.

The International Project of the Year Award recognises projects that have delivered geotechnical innovation that stands out on the international stage for credentials in sustainability, health and safety, and value engineering.

Before the awards, all finalists attended face-to-face judging by members of the 43-strong jury, made up of clients, contractors, consultants and academics. Image: Screen grab from Mainmark video]

[Image: Screengrab from Mainmark video]

Don't forget to register for the Australian Engineering Conference 2016 in Brisbane on November 23-25.