Tobias Smith , GM, Prestressed Timber Ltd - Speaking at Seismics and the City 2015

PreStressed Timber Limited – info@prestressedtimberltd.co.nz
Smart and Sustainable Buildings for
New Zealand
Dr. Tobias Smith
General Manager, PreStressed Timber Ltd., Christchurch, New Zealand

The Christchurch Earthquake
Main quake:
4 September 2010, 4.30am. M 7.1.
No deaths www.all-geo.org

CENTRAL CITY AND NZS1170 SPECTRA
CLASS D DEEP OR SOFT SOIL
Larger Horizontal Components
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Period T(s)
SA(T)(g)
NZS11
NZS11
Soft S
CHHC
CCCC
CBGS
REHS
GM_L
Design spectrum1.0
0.5
1.5
0.0
Spectralacceleration(g)
0.0 1.0 2.0 3.0 4.0
Building period (s)

Damage to the city

What does Christchurch Look like now?
Courtesy of W. Y. Kam

Timber Structures in the CHCH EQ
What does Christchurch look like now?
Courtesy of W. Y. Kam

PreStressed Timber Limited – info@prestressedtimberltd.co.nzCourtesy of M. Taylor

Timber Structures in the CHCH EQ
What does Christchurch look like now?
Courtesy of M. Taylor

Current seismic design practice
Our current design choices
Earthquake engineering philosophy
Minor earthquake No damage
Moderate earthquake Repairable damage
Big earthquake No deaths, Damage is ok
Not good enough
Society wants more

Our current design choices
This building displayed almost
prefect ‘good’ seismic behavior
Courtesy of S. Pampanin

This was our choice for Christchurch following a major earthquake
Repair is just too expensive,
and people are nervous about the results
Courtesy of A. Buchanan
Is this Smart? Or Sustainable?

We need to shift the goal posts
Updating our thinking to performance based design
Higher expectations of modern society ( “the three Ds”):
• No victims nor collapse (Deaths)
• Minimum level of damage or direct costs (Damage = Dollars)
• Minimum business interruption and recovering (indirect) costs (Downtime)

PREStressed – LAMinated Timber:
GLUe – LAMinated: GLULAM
CROSS-LAMinated: CROSS-LAM
Smith et al.

“Bill and Ben at 10” TVNZondemand

Pres-Lam
Damage Limiting System
(c/o Miss S. Nakaki) (Palermo et al. 2005)
• Originally conceived for reinforced concrete (PRESSS)
• Combination of post-tensioning cable and (in high siesmic areas) internal or external
reinforcing
• Separates ductility from material damage

Demolish
Repair
Pres-Lam – now that’s Smart
Damage Limiting System
Pres-Lam changes the way in which a system remains following earthquake loading, replacing
damaged reinforcing following a major event
Courtesy of S. PampaninCourtesy of A. Buchanan

Testing of Pres-Lam Systems
Wall systems
Pres-Lam walls with internal and external reinforcing.
Testing has also been performed on the transfer of forces within a Pres-Lam frame,
Economics of connections.
Sarti et al. Moroder et al.

Testing of Pres-Lam Systems
Moment Cross-Lam Stairwell
Dunbar et al.

Pres-Lam in Practice
The first Pres-Lam Building in the World
Courtesy of A. Buchanan
Architect: Irving Smith Jack, Engineer: Aurecon

The first Pres-Lam Building in the World
Photo: Irving Smith Jack Architects
Architect: Irving Smith Jack, Engineer: Aurecon

The first Pres-Lam Auditorium in the World
Photo: Carterton District Council
Architect and Engineer: Opus International

A gravity dominated Pres-Lam Frame Architect: Athfeild Architects, Engineer: Dunning Thornton Consultants
Photo: Trends Magazine NZ
Photo: Trends Magazine NZ

Other Examples of Pres-Lam
Concrete Columns,
Timber Beams and
Base Isolated
Cross-Lam Panels
incorporating
sections of LVL
Pres-Lam Frames only
Architect: Rick Proko, Engineer: Ruaumoko
Architect: Design Base, Engineer: Nelson Timber Solutions
Architect: Sheppard and Rout, Engineer: Kirk Roberts

Current Trends in Timber Design
The World’s getting Taller
Reiulf Ramstad Arkitekter As
mgb ARCHITECTURE + DESIGN Equilibrium,
LMDG Ltd, BTY Group
SOM Skidmore Owings and Merrell
Norway Canada USA
Barentshus Tower Tall wood proposal Timber Tower Chicago

These aren’t just pipe dreams
55 m - 15 storey - All timber building – Pres-Lam walls

1. Time and cost of construction
2. Renewable resource
3. Carbon negative
4. Light weight
5. Lovely appearance
6. Excellent performance
Why is wood smart?
Re-building Christchurch

Half of national wood production is
exported as logs
Is that smart?
Why not export pre-manufactured
buildings?
Forestry in New Zealand

Exporting Kiwi Technology and Timber
A timber building
• Grown in New
Zealand
• Processed in New
Zealand
• Pre-fabricated in
New Zealand
• Ground broken in
Japan to be erected
in June

Conclusions

Conclusions
The more trees we plant, and grow,
and harvest, and use, and replant, the better
for our health, wealth, and a sustainable planet

The Largest Pres-Lam Building
Photo: Conorboyd Photography
Architect and Engineer: Opus International

Tobias Smith , GM, Prestressed Timber Ltd - Speaking at Seismics and the City 2015

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Tobias Smith , GM, Prestressed Timber Ltd - Speaking at Seismics and the City 2015