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Performance of Masonry Structuresin Christchurch, New Zealand 

during the 2010/2011 Earthquakes

Arturo E. Schultz

Department of Civil Engineering

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Contributors

Dmytro Dizhur                Charlotte Knox         Hossein Derekhshan             Najif Ismail                        Lisa Moon

Auckland, NZ                   Auckland, NZ                 Aurecon, NZ                    Auckland, NZ               Adelaide, Australia

Jason Ingham                        Mike Griffith

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

NZ URM Building Stock

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Tectonic Activity in New Zealand

Japan

Taiwan

Chile

California

New Zealand

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

2010/2011 Earthquakes

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Sept & Oct 2010

Nov & Dec 2010

Jan & Feb (15th) 2011

Feb 22nd – Mar 28, 2011

Earthquake Sw

arm

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Areas surveyed

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

URM = 52%

Of URM, 48% red

Red URM = 24.8%

Some buildings worse than appear from street front

Say about 1 in 3 redoverall

CBD Building Damage Survey after 22 Feb. 2011 

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Out‐of‐plane failures

Diaphragm flexibility responsible for failureNote the anchorages into roof diaphragm

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Pier failures

Diagonal pier failure reasonably well understoodSpandrel failure over arched windows requires more attention

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Spandrel failures

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Pounding damage

Widespread examples of pounding damage

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Pounding damage

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Mixed Mode failure(In‐plane, Out‐of‐plane, corner effects)

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Awnings/canopies and anchorage failures

Failures observed at bothends of braces

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Cavity construction often lackedheader bricks to tie the wythes

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

StoneUnrein. (?) concreteBrickPlaster

St James  Church (1926), Riccarton; wall composition23017022010

Damage to rubble masonry construction in Holy Trinity church (1872), Avonside

Damage to brick masonry in St Luke’s church (1859), Christchurch

Damage to a gable in St James church (1926), Riccarton

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

The Christchurch Cathedral

[1888] [February 2011]

The Cathedral was designed by the Englishman G.G. Scott and work began on it in 1863. The tower and spire, paid for by the Rhodes family, are complete in the photograph but were damaged multiple times by earthquakes in 1881, 1888 and 1901.

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

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Spectra for 22 Feb. 2011 Ground Motions

CENTRAL CITY AND NZS1170 SPECTRACLASS D DEEP OR SOFT SOILLarger 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)

NZS1170 2500-yr Class D

NZS1170 500-yr Class D Deep orSoft Soil

CHHC_MaxH_FEB

CCCC_MaxH_FEB

CBGS_MaxH_FEB

REHS_MaxH_FEB

GM_Larger_FEB

Capacity

Demand

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Poor quality of diaphragm timber

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Poor quality of mortar

Many samples tested Compression strengths were 1.0 – 1.5 MPa(150 – 200 psi)

= co + µ∙v

v is low  Vertical acc’s high

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Is this what we should expect?

• Yes. URM buildings consistently collapse inlarge earthquakes

• The NZ URM building stock is analogous tothat of other European colonies. Past failureselsewhere have relevance to NZ.

• Unretrofitted URM buildings were loaded toabout 6 times their calculated capacity.

• Why did not ALL URM buildings collapsecompletely?

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Short duration of ground shaking(Less than 10 seconds of string ground shaking on both occasions)

0 10 20 30 40 50 60-0.30

-0.15

0

0.15

0.30

Time(s)

Acc

elera

tion(g

)

N64E

4 Sept 2010

22 Feb 2011

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Progressive Damage from Repeated Events

[1906] [2010]

[Sept.  [Feb. 2010] 2011]

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

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Progressive Damage from Repeated Events

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Implications for NZ and elsewhere?

• The URM building stock in NZ is remarkably homogeneous & similar to that in central US

• Similar outcomes can be expected anywhere in NZ and central US after a large earthquake

OPTIONS:

1.Do nothing

2.Seismic improvement

3.Demolition

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Steel strong backs generally performed well

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Steel Frames

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

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Shotcrete 

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

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Textile Reinforced Mortar

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Excellent success of horizontal and vertical post‐tensioning

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Floor Diaphragm Retrofits

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Unsuccessful Parapet Strengthening

Wall has detached from struts

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Unsuccessful Retrofit Diaphragm Connections

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Through Plate Anchor Failures

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Failure of epoxy bonded connections

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Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

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Field Study of Adhesive Anchor Performance

Anchor Test 054 / Building A / Adhesive 1 / Sleeved / Straight / 16mm / 400mm depth

Performance of Masonry Structures in Christchurch,New Zealand during the 2010/2011 Earthquakes

Arturo E. Schultz

Conclusions & Recommendations• Massive loss of architectural heritage: “Christchurch now has no 

earthquake‐prone buildings”. What about the central US?

• Clear lesson for NZ and central US regarding earthquake prone buildings”: Improve or remove! 

• Negative impacts from the Christchurch experience:

– Futility is spreading: public lacks of confidence in URM

– Insurance companies claim that they will not insure strengthened URM buildings

– Buildings are being demolished that would previously not have been ‘red‐carded’

• Better knowledge of URM buildings and materials needed.

• Success of a number of retrofit technologies was shown.

• Retrofit diaphragm connections require further study.