Rebuilding the Garden CityImpacts to the Canterbury BuiltEnvironmentJohn Hare, Holmes Consulting Group,Christchurch
Outline1.   Brief summary of findings2.   Overview of damage, by building type3.   Summary of outcomes4.   Discussion5.   ...
Conclusions• The Christchurch Earthquakes have provided some  valuable lessons on building performance – especially  concr...
Conclusions• Proximity issues should be considered, especially  for critical facilities• Other hazards must be considered,...
Damage•   Residential•   Heritage•   Commercial – Low and Medium Rise•   Commercial – High Rise•   Infrastructure         ...
Damage•   Residential•   Heritage•   Commercial – Low and Medium Rise•   Commercial – High Rise•   Infrastructure         ...
Shaking Damage                 7
Shaking Damage                 8
Shaking Damage                 9
Shaking Damage     Rolleston Courts        Cambridge Courts                        10
Shaking Damage                 11
Shaking Damage                 12
Liquefaction/Lateral Spread                    13
Liquefaction/Lateral Spread                    14
Liquefaction/Lateral Spread                    15
Liquefaction/Lateral Spread                    16
Cliff tops             17
Cliff tops             18
Cliff tops             19
Cliff Collapse                 20
Cliff Collapse                 21
Rockfall           22
Rockfall           23
Rockfall           24
Rockfall           25
Damage•   Residential•   Heritage•   Commercial – Low and Medium Rise•   Commercial – High Rise•   Infrastructure         ...
Christchurch Cathedral                   27
Christchurch Cathedral                   28
St Pauls Church. Madras Street                   29
Press Company                30
Press Company                31
Knox Church              32
Arts Centre – College Hall                    33
Arts Centre – Clock Tower                   34
Arts Centre - Observatory                    35
Arts Centre - Observatory                    36
Basilica           37
Durham Street Methodist Church                  38
Damage•   Residential•   Heritage•   Commercial – Low and Medium Rise•   Commercial – High Rise•   Infrastructure         ...
Colombo Street                 40
Manchester Street                    41
Tuam Street              42
Colombo Street                 43
Worcester Towers                   44
CTV      45
CTV      46
CTV      47
PGC Building               48
PGC Building               49
Crowne Plaza               53
CDHB Carpark               57
CDHB Carpark               58
CDHB Carpark               59
CDHB Carpark               61
Anonymous!             62
Harcourts            63
123 Victoria Street                      64
65
Damage•   Residential•   Heritage•   Commercial – Low and Medium Rise•   Commercial – High Rise•   Infrastructure         ...
Grand Chancellor                   69
Grand Chancellor                   70
Grand Chancellor                   71
Grand Chancellor                   72
Grand Chancellor                   73
Copthorne            74
Copthorne            75
Copthorne            78
Forsyth Barr               80
Forsyth Barr               81
Gallery apartments                     88
Gallery Apartments                     89
Damage•   Residential•   Heritage•   Commercial – Low and Medium Rise•   Commercial – High Rise•   Infrastructure         ...
Bridges          91
Bridges          92
In-ground services                     93
Roading          94
OverallOutcomes   95
Immediately following the Feb 22 earthquake• 185 people dead  –   115 in CTV building  –   18 in PGC building  –   5 throu...
Demolitions, CBD and suburbs                  Partial      Demolish   TotalCivil Defence       66           241       307O...
General Observations - Commercial• Commercial  – Most modern buildings performed as expected,    with a few exceptions  – ...
Building Performance• Approx 8,000  commercial  buildings in Chch• Approx 1200  currently slated  for demolition   – 900 i...
100
101
102
103
104
Why? 105
Context – Built environment• Settled in mid-1800s• Construction types   – First buildings in timber from 1840’s   – Stone ...
Context – Christchurch building profile • Commercial                                                  Residential         ...
Earthquake shaking in two events                                      5% Damped Spectra (North-South)                     ...
Why?• Ductility and Capacity design – design for  damage• Ground ‘failure’   – Liquefaction   – Differential settlement   ...
Why?• Levels of insurance cover   –   Chile         27%   –   Mexico        21%   –   California    17%   –   Italy       ...
Insurance• Overall insured losses estimated at  $30B – 3rd largest insurance event of  its kind.• Process difficult   – Sl...
General Observations - Residential• Houses performed well structurally   – Light wood-framed construction – no collapses, ...
Land Zones             115
Repairs• EQC cover from $10,000-$100,000   – Fletcher EQR   – 31,010 homes repaired to end Jan 2013   – 65,000+ to go…..• ...
Infrastructure Rebuild• Progress (Nov 2012)   –   Completed 206 projects, totalling $80M   –   88 projects underway, total...
Preparedness• Training of engineers• Strengthening of Buildings - DO IT!!!!  It is too late after the earthquake   – Stren...
Shoring – how to                   120
...and how not to                    121
...and how not to                    122
Heritage Apartments                  124
208 Madras Street                    125
CCC Tuam Street                  126
Christchurch Art Gallery• Temporary use as  emergency operations  centre                    127
Issues affecting    recovery      128
Temporary Facilities                       129
130
131
Residential• Availability of land   – Valuations based on 2008     values   – New sections inflated in price• Insurance   ...
DBH Map 2                  133            133
Commercial• Prior to earthquake:   –   4M sq ft of commercial office in CBD   –   2.75M sq ft needed   –   Class A office ...
Planning• City plan rewrite   – Height limits?   – Urban planning     considerations• Land ownership   – Mainly small,    ...
Central City Map                   136
New Building Design• Owners’ expectations  – Make it like a hospital in    Wellington!  – Low damage design  – Existing Us...
Building Evaluation & Repair• Detailed Engineering  Evaluations  – For all non-residential    structures  – Approx 2000 su...
Detailed Engineering Evaluation Procedure – What is it?• Developed by Engineering Advisory Group  (to DBH)• Process of ins...
Canterbury Earthquakes Royal Commission(CERC)• Seven volumes of report,  covering:   – Seismicity and soils   – Performanc...
NZ Wide – Earthquake Prone Buildings• Consultation process  underway following  CERC report• Dilemma   – %NBS?   – Or some...
EPB Myth No 1 – Capacity Matters• Current criteria for EPB – 33%NBS• But what causes failure of buildings in  earthquake? ...
Guess some scores            9%                    143
Guess some scores           67%                    144
NZ Wide – Codes and Standards• Following CERC  MBIE  Updated  code  – When? Next 2-4 years?  – Submissions?  – Long proc...
Conclusions•   The Christchurch Earthquakes have provided some valuable lessons    on building performance – especially co...
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Rebuilding the Garden City (Impacts to the Canterbury Built Environment) - John Hare

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2013 EERI Annual Meeting Session: Christchurch Earthquakes Workshop

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  • The Christchurch Earthquakes Workshop, Seattle, Feb 12, 2013 John Hare, Holmes Consulting Group, Christchurch
  • The Christchurch Earthquakes Workshop, Seattle, Feb 12, 2013 John Hare, Holmes Consulting Group, Christchurch These are all over Christchurch, particularly in older suburbs. House on right is historic homestead close to epicentre. Ironically, many chimneys no longer operative due to Chch clean air regulations, btu had not been removed. Many houses with this sort fo damage otherwise ok.
  • The Christchurch Earthquakes Workshop, Seattle, Feb 12, 2013 John Hare, Holmes Consulting Group, Christchurch S38/39 Initiated by: CERA – 774 Owner – 137 Process: Structural engineers assessment of each building within the cordon and subsequent report on findings (‘scored” according to risk of collapse/public safety/potential occupancy risk, etc) Report and decision made under CER Act communicated to owner about what is to be done Owner selects option to owner-initiate or CERA to manage Initially CERA took the lead in determining demolition of dangerous buildings, but as time progressed, it has often been a building owner’s insurer’s engineers that have alerted CERA to buildings damaged to below one-third Building Code. Process: Structural engineers assessment of each building within the cordon and subsequent report on findings (‘scored” according to risk of collapse/public safety/potential occupancy risk, etc) Report and decision made under CER Act communicated to owner about what is to be done Owner selects option to owner-initiate or CERA to manage Initially CERA took the lead in determining demolition of dangerous buildings, but as time progressed, it has often been a building owner’s insurer’s engineers that have alerted CERA to buildings damaged to below one-third Building Code.
  • The Christchurch Earthquakes Workshop, Seattle, Feb 12, 2013 John Hare, Holmes Consulting Group, Christchurch
  • Rebuilding the Garden City (Impacts to the Canterbury Built Environment) - John Hare

    1. 1. Rebuilding the Garden CityImpacts to the Canterbury BuiltEnvironmentJohn Hare, Holmes Consulting Group,Christchurch
    2. 2. Outline1. Brief summary of findings2. Overview of damage, by building type3. Summary of outcomes4. Discussion5. Some lessons learnt6. Issues for the recovery7. Recap conclusions 2
    3. 3. Conclusions• The Christchurch Earthquakes have provided some valuable lessons on building performance – especially concrete structures – More research is required• Our older building stock needs greater consideration – A capacity based evaluation only identifies part of the problem – Our buildings’ vulnerabilities need to be better understood• Faster action is required to address these issues – A passive approach is too slow and ineffective 3
    4. 4. Conclusions• Proximity issues should be considered, especially for critical facilities• Other hazards must be considered, eg rockfall, lateral spread• Training is required to maximise preparedness – Of engineering profession – Of the general public 4
    5. 5. Damage• Residential• Heritage• Commercial – Low and Medium Rise• Commercial – High Rise• Infrastructure 5
    6. 6. Damage• Residential• Heritage• Commercial – Low and Medium Rise• Commercial – High Rise• Infrastructure 6
    7. 7. Shaking Damage 7
    8. 8. Shaking Damage 8
    9. 9. Shaking Damage 9
    10. 10. Shaking Damage Rolleston Courts Cambridge Courts 10
    11. 11. Shaking Damage 11
    12. 12. Shaking Damage 12
    13. 13. Liquefaction/Lateral Spread 13
    14. 14. Liquefaction/Lateral Spread 14
    15. 15. Liquefaction/Lateral Spread 15
    16. 16. Liquefaction/Lateral Spread 16
    17. 17. Cliff tops 17
    18. 18. Cliff tops 18
    19. 19. Cliff tops 19
    20. 20. Cliff Collapse 20
    21. 21. Cliff Collapse 21
    22. 22. Rockfall 22
    23. 23. Rockfall 23
    24. 24. Rockfall 24
    25. 25. Rockfall 25
    26. 26. Damage• Residential• Heritage• Commercial – Low and Medium Rise• Commercial – High Rise• Infrastructure 26
    27. 27. Christchurch Cathedral 27
    28. 28. Christchurch Cathedral 28
    29. 29. St Pauls Church. Madras Street 29
    30. 30. Press Company 30
    31. 31. Press Company 31
    32. 32. Knox Church 32
    33. 33. Arts Centre – College Hall 33
    34. 34. Arts Centre – Clock Tower 34
    35. 35. Arts Centre - Observatory 35
    36. 36. Arts Centre - Observatory 36
    37. 37. Basilica 37
    38. 38. Durham Street Methodist Church 38
    39. 39. Damage• Residential• Heritage• Commercial – Low and Medium Rise• Commercial – High Rise• Infrastructure 39
    40. 40. Colombo Street 40
    41. 41. Manchester Street 41
    42. 42. Tuam Street 42
    43. 43. Colombo Street 43
    44. 44. Worcester Towers 44
    45. 45. CTV 45
    46. 46. CTV 46
    47. 47. CTV 47
    48. 48. PGC Building 48
    49. 49. PGC Building 49
    50. 50. Crowne Plaza 53
    51. 51. CDHB Carpark 57
    52. 52. CDHB Carpark 58
    53. 53. CDHB Carpark 59
    54. 54. CDHB Carpark 61
    55. 55. Anonymous! 62
    56. 56. Harcourts 63
    57. 57. 123 Victoria Street 64
    58. 58. 65
    59. 59. Damage• Residential• Heritage• Commercial – Low and Medium Rise• Commercial – High Rise• Infrastructure 68
    60. 60. Grand Chancellor 69
    61. 61. Grand Chancellor 70
    62. 62. Grand Chancellor 71
    63. 63. Grand Chancellor 72
    64. 64. Grand Chancellor 73
    65. 65. Copthorne 74
    66. 66. Copthorne 75
    67. 67. Copthorne 78
    68. 68. Forsyth Barr 80
    69. 69. Forsyth Barr 81
    70. 70. Gallery apartments 88
    71. 71. Gallery Apartments 89
    72. 72. Damage• Residential• Heritage• Commercial – Low and Medium Rise• Commercial – High Rise• Infrastructure 90
    73. 73. Bridges 91
    74. 74. Bridges 92
    75. 75. In-ground services 93
    76. 76. Roading 94
    77. 77. OverallOutcomes 95
    78. 78. Immediately following the Feb 22 earthquake• 185 people dead – 115 in CTV building – 18 in PGC building – 5 through rockfall – 2 infants at home – 41 through falling masonry – 4 related effects, after the quake• 6,500 injured• 12,000 homes evacuated immediately 96
    79. 79. Demolitions, CBD and suburbs Partial Demolish TotalCivil Defence 66 241 307Owner initiated 166 233 399CER Act s.38/39issued 198 713 911Total 430 1,187 1,617 97
    80. 80. General Observations - Commercial• Commercial – Most modern buildings performed as expected, with a few exceptions – Most modern of modern buildings (post-1995) performed well – More damage to irregular and older structures – Unstrengthened/unsecured masonry buildings essentially destroyed – Well strengthened masonry buildings performed moderately well to very well 98
    81. 81. Building Performance• Approx 8,000 commercial buildings in Chch• Approx 1200 currently slated for demolition – 900 in CBD – 300 outer• These numbers likely to rise 99
    82. 82. 100
    83. 83. 101
    84. 84. 102
    85. 85. 103
    86. 86. 104
    87. 87. Why? 105
    88. 88. Context – Built environment• Settled in mid-1800s• Construction types – First buildings in timber from 1840’s – Stone and brick buildings 1850s to 1935 • 96 Stone masonry = 1/3 of all NZ stone masonry – RC and Steel from early 1900s – Most residential construction timber frame• Seismic design provisions from 1935 – First specific seismic code 1965 – Capacity Design introduced 1976 – Non-specific timber and RM construction 1980s – Full modern provisions from 1995 106
    89. 89. Context – Christchurch building profile • Commercial Residential Unreinforced masonry Reinforced MasonryWalls and Braced Unstrengthened Frames Masonry Strengthened Masonry Moment Frames Timber frame Holmes Consulting Group (estimate) Beattie (BRANZ) 108
    90. 90. Earthquake shaking in two events 5% Damped Spectra (North-South) 5% Damped Spectra (West-East) 1.80 1.60 1.80 Christchurch Botanic Gardens S01W Christchurch Botanic Gardens N89W Christchurch Botanic Gardens N89W Christchurch Hospital N01W Christchurch Hospital S89W 1.60 1.40 Christchurch Hospital S89W Christchurch Resthaven N02E 1.60 Christchurch Resthaven S88E Christchurch Resthaven S88E Christchurch Cathedral College N26W Christchurch Cathedral Cathedral College N64E Christchurch College N64E NZS1170 Spectra, Z=0.3, Soil Class D, IL2, ULS 1.40 NZS1170 Spectra, Z=0.22, Soil Class D, IL2, ULS 1.40 1.20 NZS1170 NZS1170Z=0.3, Soil Class SoilIL2, ULS IL2, ULS Spectra, Spectra, Z=0.3, D, Class D, NZS1170 NZS1170Z=0.22, Soil Class Soil Class D, IL2, ULS Spectra, Spectra, Z=0.22, D, IL2, ULS 1.20 1.20 1.00 Acceleration (g)Acceleration (g) Acceleration (g) 1.00 1.00 0.80 0.80 0.80 0.60 0.60 0.60 0.40 0.40 0.40 0.20 0.20 0.20 0.00 0.00 0.00 0.00 1.00 2.00 3.00 4.00 5.00 6.00 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 5.00 5.00 6.00 Period (Seconds) Period (Seconds) (Seconds) Period September 4th February 22nd 109
    91. 91. Why?• Ductility and Capacity design – design for damage• Ground ‘failure’ – Liquefaction – Differential settlement – Tilt up to 1 in 150 acceptable?• Low cycle fatigue – How much life is left in that steel? – Testing showing many buildings have exceeded half of the reinforcement strain capacity• Repair costs – >70% of value - gone 111
    92. 92. Why?• Levels of insurance cover – Chile 27% – Mexico 21% – California 17% – Italy 14% – Japan 12-17% – Turkey 4% – Haiti 1% – New Zealand 80% Source: Swiss Re 112
    93. 93. Insurance• Overall insured losses estimated at $30B – 3rd largest insurance event of its kind.• Process difficult – Slow settlements – Communication between clients and insurers, insurers and reinsurers• But what in the future? – Higher cost of insurance – Tighter conditions – Less availability 113
    94. 94. General Observations - Residential• Houses performed well structurally – Light wood-framed construction – no collapses, generally repairable• Most failures due to ground performance• 561,000 tons of silt removed• 7,860 houses declared ‘red zone’, i.e. Government buy-back of land, relocate• 6,315 residential owners agreed to sell to government so far (as at Dec 2012)• 10,000 people estimated to have left Christchurch• Unclear how many coming back, or when 114
    95. 95. Land Zones 115
    96. 96. Repairs• EQC cover from $10,000-$100,000 – Fletcher EQR – 31,010 homes repaired to end Jan 2013 – 65,000+ to go…..• Private Insurers above $100,000 – More than 12,000 homes estimated as major repairs or rebuild – Most spread over 12 insurers 116
    97. 97. Infrastructure Rebuild• Progress (Nov 2012) – Completed 206 projects, totalling $80M – 88 projects underway, totalling $220M – Further projects in train for total of $1.5B – 11 miles of fresh water pipe laid – 30 miles of wastewater pipe laid – 2 miles of stormwater pipe laid – 19 acres of road pavement laid – 745 miles (of 1006) of wastewater pipe videoed – 415 miles (of675) of stormwater pipe videoed• Total cost expected to exceed $5B 117
    98. 98. Preparedness• Training of engineers• Strengthening of Buildings - DO IT!!!! It is too late after the earthquake – Strengthen EPBs – 67% if possible – Secure non-structural elements – Re-evaluate critical weakness – more later• Proximity effects• Communication to the public – What to do – Expectations for buildings – Self-reliance 119
    99. 99. Shoring – how to 120
    100. 100. ...and how not to 121
    101. 101. ...and how not to 122
    102. 102. Heritage Apartments 124
    103. 103. 208 Madras Street 125
    104. 104. CCC Tuam Street 126
    105. 105. Christchurch Art Gallery• Temporary use as emergency operations centre 127
    106. 106. Issues affecting recovery 128
    107. 107. Temporary Facilities 129
    108. 108. 130
    109. 109. 131
    110. 110. Residential• Availability of land – Valuations based on 2008 values – New sections inflated in price• Insurance – Insurers still not re-entering market with confidence• Sale of properties – Only to certain buyers – Repairs still to be completed limiting sales• Standards for repair and rebuild 132
    111. 111. DBH Map 2 133 133
    112. 112. Commercial• Prior to earthquake: – 4M sq ft of commercial office in CBD – 2.75M sq ft needed – Class A office space about $30/sq ft – Class B office space about $22-25/sq ft• Post earthquake – Many tenants relocated out of CBD to office parks on leases of 4 years plus – Some businesses relocated out of city – Current demand estimate 1.8M sq ft – New building rentals $45/sq ft (class A) 134
    113. 113. Planning• City plan rewrite – Height limits? – Urban planning considerations• Land ownership – Mainly small, closely held ownership – Amalgamation of titles? 135
    114. 114. Central City Map 136
    115. 115. New Building Design• Owners’ expectations – Make it like a hospital in Wellington! – Low damage design – Existing Use rights – Individual owner vs institutional developer• Building Code updates? 137
    116. 116. Building Evaluation & Repair• Detailed Engineering Evaluations – For all non-residential structures – Approx 2000 submitted, 1000 approved• Temporary stability concerns• Strengthening design loads 138
    117. 117. Detailed Engineering Evaluation Procedure – What is it?• Developed by Engineering Advisory Group (to DBH)• Process of inspection, review and reporting – Qualitative Procedure – Quantitative Procedure – not always required• Documents available at www.sesoc.org.nz – Engineers briefed at CSG meetings – Process is an overlay to work completed already, not necessarily additional 139
    118. 118. Canterbury Earthquakes Royal Commission(CERC)• Seven volumes of report, covering: – Seismicity and soils – Performance of CBD buildings – Low damage design technology – Earthquake Prone Buildings – CTV collapse – Roles and responsibilities – Summary and recommendations 140
    119. 119. NZ Wide – Earthquake Prone Buildings• Consultation process underway following CERC report• Dilemma – %NBS? – Or something else? 141
    120. 120. EPB Myth No 1 – Capacity Matters• Current criteria for EPB – 33%NBS• But what causes failure of buildings in earthquake? – Refer DEEs and IEPs…. 142
    121. 121. Guess some scores 9% 143
    122. 122. Guess some scores 67% 144
    123. 123. NZ Wide – Codes and Standards• Following CERC  MBIE  Updated code – When? Next 2-4 years? – Submissions? – Long process……• SESOC – Practice Note – Design Of Conventional Structural Systems Following The Canterbury Earthquakes – Available for use now – Uptake? 145
    124. 124. Conclusions• The Christchurch Earthquakes have provided some valuable lessons on building performance – especially concrete structures – More research is required• Our older building stock needs greater consideration – A capacity based evaluation only identifies part of the problem – Our buildings’ vulnerabilities need to be better understood• Faster action is required to address these issues – A passive approach is too slow and ineffective• Proximity issues should be considered, especially for critical facilities• Other hazards must be considered, eg rockfall, lateral spread• Training is required to maximise preparedness – Of engineering profession – Of the general public 146

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