Seismic performance of single-storey light timber-framed buildings braced …

Research papers, University of Canterbury Library

Light timber framed (LTF) structures provide a cost-effective and structurally efficient solution for low-rise residential buildings. This paper studies seismic performance of single-storey LTF buildings sheathed by gypsum-plasterboards (GPBs) that are a typical lining product in New Zealand houses. Compared with wood-based structural panels, GPBs tend to be more susceptible to damage when they are used in bracing walls to resist earthquake loads. This study aims to provide insights on how the bracing wall irregularity allowed by the current New Zealand standard NZS 3604 and the in-plane rigidity of ceiling diaphragms affect the overall seismic performance of these GPB-braced LTF buildings. Nonlinear time-history analyses were conducted on a series of single-storey baseline buildings with different levels of bracing wall irregularities and ceiling diaphragm rigidity. The results showed significant torsional effect caused by the eccentric bracing wall layout with semi-rigid/rigid ceiling diaphragms. On average, bracing wall drift demand caused by the extreme bracing wall irregularities was three times of that in the regular bracing wall layout under the rigid diaphragm assumption. This finding agreed well with the house survey after the 2011 Canterbury Earthquake in which significantly more damage was observed in the houses with irregular bracing wall layouts and relatively rigid diaphragms. Therefore, it is recommended to limit the level of bracing wall eccentricity and ensure the sufficiently rigid diaphragms to avoid excessive damage in these LTF buildings in future events.

Photograph by Jocelyn Kinghorn 1861

Images, UC QuakeStudies

Damage to a residential house. A relatively intact wall is being supported with wooden bracing.

Photograph by Jocelyn Kinghorn 073

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Steel bracing erected against the wall of a damaged building to prevent any further damage.

Photograph of 191 Armagh Street (12)

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A photograph of the front of 191 Armagh Street, with wooden bracing holding the wall together.

Photograph of Deans farm buildings, 29 Kahu Road (7)

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A photograph of the steal bracing holding up the walls of Deans farm buildings on Kahu Road.

Koen Broekema's Photograph 154

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A close up of the entrance to the cathedral. Bricks have fallen from the wall causing damage to the balustrade. Bracing has been placed against the front wall to limit further damage.

Photograph by Jocelyn Kinghorn 2648

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Damaged building in Christchurch central, steel bracing and scaffolding are used to support the walls on the building.

Koen Broekema's Photograph 020

Images, UC QuakeStudies

The front of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the front wall to limit further damage.

Koen Broekema's Photograph 135

Images, UC QuakeStudies

The front of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the front wall to limit further damage.

Koen Broekema's Photograph 057

Images, UC QuakeStudies

The front of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the front wall to limit further damage.

Photograph by Jocelyn Kinghorn 421

Images, UC QuakeStudies

A house with wooden bracing supporting the front wall. On the fence are tape and spray painted USAR codes.

Koen Broekema's Photograph 087

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A close up of the damaged stonework of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the wall to limit further damage.

Koen Broekema's Photograph 036

Images, UC QuakeStudies

A close up of the front of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the front wall to limit further damage.

Koen Broekema's Photograph 027

Images, UC QuakeStudies

A close up of the damaged stonework of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the wall to limit further damage.

Koen Broekema's Photograph 072

Images, UC QuakeStudies

A close up of the front of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Bracing has been placed against the front wall to limit further damage.

Koen Broekema's Photograph 084

Images, UC QuakeStudies

A close up of the front of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the wall to limit further damage.

Photograph of Deans farm buildings, 29 Kahu Road (3)

Images, UC QuakeStudies

A photograph of Deans farm buildings on Kahu Road. Steel bracing has been used to hold the walls together.

Photograph of Deans farm buildings, 29 Kahu Road (2)

Images, UC QuakeStudies

A photograph of Deans farm buildings on Kahu Road. Steel bracing has been used to hold the walls together.

Photograph of Deans farm buildings, 29 Kahu Road (1)

Images, UC QuakeStudies

A photograph of Deans farm buildings on Kahu Road. Steel bracing has been used to hold the walls together.

Photograph of Deans farm buildings, 29 Kahu Road (11)

Images, UC QuakeStudies

A photograph of Deans farm buildings on Kahu Road. Steel bracing has been used to hold the walls together.

Photograph of Deans farm buildings, 29 Kahu Road (4)

Images, UC QuakeStudies

A photograph of Deans farm buildings on Kahu Road. Steel bracing has been used to hold the walls together.

Photograph of Deans farm buildings, 29 Kahu Road (6)

Images, UC QuakeStudies

A photograph of Deans farm buildings on Kahu Road. Steel bracing has been used to hold the walls together.

Photograph by Eroica Ritchie 148

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The west face of the damaged ChristChurch Cathedral. Steel bracing supports the wall where the Rose Window has collapsed.

Koen Broekema's Photograph 104

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The front of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the wall to limit further damage. The Citizens' Memorial statue stands to the left.

Koen Broekema's Photograph 132

Images, UC QuakeStudies

The front of Christ Church Cathedral. The upper part of the front wall has crumbled leaving the inside space exposed. Steel bracing has been placed against the front wall to limit further damage. The Citizens' Memorial statue stands to the left.

Koen Broekema's Photograph 122

Images, UC QuakeStudies

The front of Christ Church Cathedral showing its broken tower. Bracing has been placed on the front wall to limit further damage.

Christchurch Press Image: John Kirk-Anderson 2010:09:09 15:17:08

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Bracing on a damaged section of the payroll office wall at The Press, following the Canterbury earthquakes".

Christchurch Press Image: John Kirk-Anderson 2010:09:09 15:15:42

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Photograph captioned by Fairfax, "Bracing on a damaged section of the payroll office wall at The Press, following the Canterbury earthquakes".

Photograph by Jocelyn Kinghorn 484

Images, UC QuakeStudies

Detail of earthquake damage to the Cranmer Centre. Bricks have fallen from the wall, exposing the inside rooms. Wooden bracing supports the building.

Photograph by Jocelyn Kinghorn 2437

Images, UC QuakeStudies

Reconstruction work on Our City-O-Tautahi, located in the former Municipal Chambers. Extensive bracing can be seen on front wall of the building.