Whanganui's Sarjeant Gallery redevelopment: Structural engineer says amazing building is worth saving

Structural engineers Hayden Young and Philip Yong assess the Sarjeant Gallery's walls. Photo / Supplied

Combining old with new is a challenge, but worth doing says the lead structural engineer working on the Sarjeant Gallery's redevelopment.

Philip Yong was on site examining the 100-year-old building, assessing which materials will be required with the right characteristics and strength to support the building.

There are two parts to the redevelopment project.

One is earthquake strengthening and restoration of the existing 1919 building and another is the construction of a new wing behind the gallery with a linking structure between the two.

The structural engineer is a key component in the building construction process, responsible for the design and physical integrity of the building.

Yong said a challenge is allowing for inter-building movement between the existing building and the new extension.

The buildings are very different.

The old building is rigid with stiff and brittle walls, whereas a modern building is more ductile.

He used the analogy of a crunchie bar snapping and a moro bar stretching in an earthquake.

Yong has experience with projects of immense scale and complexity, including the design of Nam Cheong station in Kowloon, the massive southern terminus of the KCRC West Rail in Hong Kong.

He has also been involved in specialist investigations looking at the long term performance of ageing structures, including the Auckland Harbour Bridge.

He has been working with the Sarjeant Gallery since 2014.

Now into the detailed design phase, Yong and his firm are working to understand the constraints of the project, such as build-ability and preserving the building's heritage.