Built to withstand the toughest forces of nature

Visually stunning, 20 Customhouse Quay, the 14-storey office building on the Wellington waterfront, is perhaps, technologically, the most advanced structural solution for high-rise buildings in New Zealand.

Designed to survive a one in 500 year earthquake with no structural damage, the building is estimated to meet 180 percent of the building code.

It features base-isolating technology, which substantially reduces the forces exerted on a building during an earthquake.

The distinctive diagrid structure (diagonallybraced columns) supports the base isolation with a significantly stronger tower frame than conventional design techniques.

It is one of the tallest buildings in New Zealand to utilise this design method. Diagrid framework is considered much stronger but also uses approximately 20 percent less steel than conventional building designs. Diagrid design eliminates most internal columns in the building thus providing large floor areas.

It also reduces the movement experienced in the building during an earthquake. Wellington-based structural steel fabricators MJH Engineering carried out the structural steelwork on this landmark project.

The company was engaged at the early stages by the developers Newcrest and worked closely with Newcrest, Scarbro Construction and Wallace Builders throughout the design and build of the project. This close working relationship from the early stages is something that MJH Engineering project manager Mark Shirtliff says was beneficial.

“With the project having many large steel components, we assisted the design team working through buildability issues. From the early stages we were involved in ensuring compliant material availability and allocating the appropriate labour resources to carry out the project to meet both quality standards

and programme,” Mark says.

He says the project had its challenges but was an exciting one to be involved in. “The key to the project running successfully was a combination of shop drawing and fabrication accuracy, machining all of the diagrid nodes and CHS braces, along with commencing fabrication at an early stage in the project to ensure supply of fabricated steel could meet the programme of the site installation.”

He says the man hours to make some members were significantly higher than the installation of the members. “With regard to installation, although it was intense it ran extremely well, due to many of the hardyards being worked through, co-ordinated and resolved prior to hitting the site.”

MJH Engineering has been one of New Zealand’s leading structural steel fabricators for over 30 years.

The company specialises in a wide range of steel work, including industrial warehouses, commercial buildings, multi-storey tower blocks, steel art works, residential buildings and seismic strengthening projects.

Over those 30 years the company has been involved in a diverse range of projects, including the ASB Sports Centre Wellington, Wellington Motorway Gantries, Manakau Institute of Technology (MIT) Auckland, Clyde Quay Apartments Wellington, Victoria University Gateway, and the Control Tower at Wellington International Airport.

The team at MJH Engineering offers a full range of capabilities, and includes estimators, quality surveyors, a comprehensive shop drawing department, fabrication team, installation team, plus a crane hire and a maintenance division.

MJH is SCNZ Steel Fabricator certified (SFC) to Category 3, which awards them with an independent certification that their quality management systems consistently result in compliant fabricated steelwork.

They have two large workshops, covered and craned, with NC beamdrill and saw, CNC plasma and profile cutting, CNC plate drilling, and CNC pipe cutter, plus a machine shop with a Berardi large 5 axis milling machine, and a paint shop for abrasive blasting and painting.

Mark says it is MJH Engineering’s experience, capabilities and reputation that has enabled them to secure contracts such as 20 Customhouse Quay.

“MJH has a strong relationship with engineers and clients, therefore we are known for good quality and capacity to get through projects. This is the first time we have worked with both Newcrest and Scarbro and it has been a success.”

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