The Effectiveness of Retrofit Technologies in Wooden-Framed Houses in Well…

Research papers, University of Canterbury Library

New Zealand has a long tradition of using light timber frame for construction of its domestic dwellings. After the most recent earthquakes (e.g. Canterbury earthquakes sequence), wooden residential houses showed satisfactory life safety performance. However, poor performance was reported in terms of their seismic resilience. Although numerous innovative methods to mitigate damage have been introduced to the New Zealand community in order to improve wooden house performance, these retrofit options have not been readily taken up. The low number of retrofitted wooden-framed houses leads to questions about whether homeowners are aware of the necessity of seismic retrofitting their houses to achieve a satisfactory seismic performance. This study aims to explore different retrofit technologies that can be applied to wooden-framed houses in Wellington, taking into account the need of homeowners to understand the risk, likelihood and extent of damage expected after an event. A survey will be conducted in Wellington about perceptions of homeowners towards the expected performance of their wooden-framed houses. The survey questions were designed to gain an understanding of homeowners' levels of safety and awareness of possible damage after a seismic event. Afterwards, a structural review of a sample of the houses will be undertaken to identify common features and detail potential seismic concerns. The findings will break down barriers to making improvements in the performance of wooden-framed houses and lead to enhancements in the confidence of homeowners in the event of future seismic activity. This will result in increased understanding and contribute towards an accessible knowledge base, which will possibly increase significantly the use of these technologies and avoid unnecessary economic and social costs after a seismic event.

Central City Tour, 4 April 2011 - Photograph 47

Images, UC QuakeStudies

The clock tower at the Arts Centre supported by steel and wooden bracing to prevent further damage.

June 2011 Earthquake - Photograph 02

Images, UC QuakeStudies

Damage to a house in Richmond. Bricks have fallen from the walls, exposing the wooden framing beneath.

22 February Earthquake - Photograph 84

Images, UC QuakeStudies

Damage to Knox Church. Bricks and stonework have fallen from the gable ends of the church, exposing the wooden framework beneath.

22 February Earthquake - Photograph 86

Images, UC QuakeStudies

Damage to Knox Church. Bricks and stonework have fallen from the gable ends of the church, exposing the wooden framework beneath.

22 February Earthquake - Photograph 83

Images, UC QuakeStudies

Damage to Knox Church. Bricks and stonework have fallen from the gable ends of the church, exposing the wooden framework beneath.

22 February Earthquake - Photograph 82

Images, UC QuakeStudies

Damage to Knox Church. Bricks and stonework have fallen from the gable ends of the church, exposing the wooden framework beneath.

June 2011 Earthquake - Photograph 01

Images, UC QuakeStudies

Flooding and liquefaction surround a house in Richmond. Bricks have fallen from the walls of the house, exposing the wooden framework beneath.

Townsend Telescope: Part Photograph 21

Images, UC QuakeStudies

A photograph of a wooden knob from the Townsend Telescope. The knob broke off the telescope during the 22 February 2011 earthquake.

22 February Earthquake - Photograph 40

Images, UC QuakeStudies

A man stands on a wooden deck. There is a visible gap between the steps and the lower decking. The photographer comments, "Decks and steps have separated".

Central City Tour, 4 April 2011 - Photograph 48

Images, UC QuakeStudies

The clock tower at the Arts Centre supported by steel and wooden bracing to prevent further damage. The photographer comments, "A bike ride around the CBD. Arts Centre".

Henry Africa's Demolition - Photograph 21

Images, UC QuakeStudies

The damaged Richmond Methodist Church is supported by wooden bracing. The photographer comments, "The church is being repaired. A few doors down from Henry Africa's, the church has had significant damage too".

Central City Tour, 4 April 2011 - Photograph 61

Images, UC QuakeStudies

Military personnel sit outside a security checkpoint tent. In the background, the stone cladding of a gable end on the Cranmer Courts building has collapsed, exposing the wooden framework beneath.

22 February Earthquake - Photograph 80

Images, UC QuakeStudies

Damage to a wooden building on Bealey Avenue. Windows on the lower storey are covered in tarpaulins. The photographer comments, "One large timber building stands, the dust from a demolition can be seen at right".

Chambers Silencio Ensemble Photograph 27

Images, UC QuakeStudies

A photograph of wooden mallets lying at the feet of a musician at 'Silencio Ensemble', an outdoor acoustic performance using tubular bells and road cones. The performance was part of FESTA 2012.

Central City Tour, 4 April 2011 - Photograph 16

Images, UC QuakeStudies

A spray-painted message on a wall of Englefield Lodge reads "We will try to save this house." Wooden bracing supports the wall. The photographer comments, "A bike ride around the CBD. Englefield, Christchurch's oldest house in Fitzgerald Ave".

Central City Tour, 4 April 2011 - Photograph 62

Images, UC QuakeStudies

A crane sits beside the damaged Cranmer Courts building. The stone cladding of a gable end of the building has collapsed, exposing the wooden framework beneath. The photographer comments, "A bike ride around the CBD. Cranmer Courts, Montreal St".

22 February Earthquake - Photograph 78

Images, UC QuakeStudies

A news crew have set up a satellite dish on the side of the road in Stoneyhurst Street. In the background is the rubble of a demolished wooden building. The photographer comments, "TV crews set up near Bealey-Papanui corner - these were in Stoneyhurst St".

UC Restarts - Photograph 27

Images, UC QuakeStudies

A damaged wooden footbridge across the Avon River beside University Drive is blocked off with sheets of plywood and danger signs. The photographer comments, "The University restarts its teaching, and the techies in e-learning move out of NZi3. The bridge to the Rec Centre".

22 February Earthquake - Photograph 79

Images, UC QuakeStudies

A news crew have set up a satellite dish on the side of the road in Stoneyhurst Street. In the background a digger sits beside the rubble of a demolished wooden building. The photographer comments, "TV crews set up near Bealey-Papanui corner - these were in Stoneyhurst St".

Canterbury Earthquake September 2010 - Photograph 13

Images, UC QuakeStudies

Damage to a house in Richmond. Part of the brick wall has slumped to one side, leaving a visible gap between the wall and a windowframe. Broken wooden framing can be seen in the gap. The photographer comments, "Cracking in the external brickwork".

Canterbury Earthquake September 2010 - Photograph 24

Images, UC QuakeStudies

Damage to a house in Richmond. Bricks have fallen from a wall, exposing the wooden framing beneath. The photographer comments, "The foundation and a section of the wall of the dining room have shifted and cracked. The dining room floor is very springy".

June 2011 Earthquake - Photograph 04

Images, UC QuakeStudies

Damage to a house in Richmond. Bricks have fallen from the walls, exposing the wooden framing beneath. Power lines between the house and a power pole have been stretched taut. The photographer comments, "The house and power pole have moved, stretching power lines taut as a guitar string".

Central City Tour, 4 April 2011 - Photograph 15

Images, UC QuakeStudies

Damage to Englefield Lodge on Fitzgerald Avenue. A pile of bricks lies in front of the house, windows are boarded up, and wooden bracing is propping up the walls. A spray-painted message on a wall reads "We will try to save this house." The photographer comments, "A bike ride around the CBD. Englefield, Christchurch's oldest house, in Fitzgerald Ave".

June 2011 Earthquake - Photograph 15

Images, UC QuakeStudies

Damage to a house in Richmond. Bricks have fallen from the walls onto the driveway, and a large gap between the concrete foundation and the wooden framing shows how much the house has moved. The photographer comments, "The foundations and brick cladding moved, but the timber wall remained in position. The gap grew to over 400mm by the time the house was demolished.

Bike Ride in the East Side - Photograph 42

Images, UC QuakeStudies

Damage to a house in Richmond. The foundation is all that remains of one room, and the exposed interior wall has been covered with builders' paper for protection. Weeds grow between cracks in the concrete patio. The photographer comments, "Revisiting our abandoned house. Cracked patio. The wooden floor is all that remains of a sunny living space with bifold doors, opening the house to the garden. This was so broken on 4/9/10 that it was immediately demolished".