Alpine Fault Scenario EQ QC Project FP2 Research 1

Alpine Fault Scenario – FP2 research Damage indices (LSN) ESA CHC Failure ALPINE FAULT SITE EFFECTS (LOCAL SOIL CONDITIONS) 2

Two Approaches Simplified analysis (conventional engineering tool) Advanced analysis (top-end research / eng. Tool) Input required: PGA contour maps (FP1) Output: LIQ damage maps (indicators of liquefaction- induced damage to land, buildings and infrastructure, in generic terms)  in absolute terms and relative to CES Input required: Acceleration time history (FP1) Output: Acc. TH, response spectra, detailed soil and site response, dynamic animations (disp. & PWP)  an extension to FP1 GM simulations LSN – damage maps 3

SIMPLIFIED METHOD: Input – PGA contours 4

SIMPLIFIED METHOD: over 20,000 CPTs Area based 5

SIMPLIFIED METHOD: Output Damage Index Maps (e.g. LSN map) 6

The Liquefaction Ground Damage Model Moderate to Severe Liquefaction land damage (LSN) Minor to Moderate None to Minor Multiple CPT (or SPT) in the area indicate some spatial variability. Some areas have more spatial variability than others. Depends on geological processes that laid down the sediment. Increasing earthquake shaking (PGA) A different set of curves for each area

The Liquefaction Ground Damage Model A different set of curves for each area due to: Soil composition Soil density Depth to groundwater Spatial variability Top set of curves are in an area of dense beach sands whereas the bottom set of graphs is for fine loose easturine deposited soils

The Liquefaction Ground Damage Model Shaking

The Building Foundation Differential Settlement Model Ground damage Shaking Liquefaction land damage (LSN) Building Foundation Differential Settlement None to Minor Minor to Moderate Moderate to Severe 95 %ile 85 %ile 50 %ile Based on building differential settlement survey data obtained from buildings affected by the CES CES = 2010-2011 Canterbury Earthquake Sequence These curves apply to light weight houses with shallow foundation systems with either concrete slabs or perimeter concrete ring beam (typically 300mm wide by 600mm high) supporting a timber floor with internal short posts nominally embedded 200 to 300mm into the ground. 15 %ile 5 %ile

The Building Foundation Differential Settlement Model Ground damage Foundation damage Shaking

The Building Loss Ratio Model Ground damage Foundation damage Shaking Building Foundation Differential Settlement Building Loss Ratio Type C Type B Building Loss Ratio = Building repair cost / building value (or replacement cost). So a value of 1 = total loss and a value of 0.1 = $30,000 damage to a $300,000 house. Type C = 100mm thick concrete slab foundation Type B = perimeter concrete ring beam (typically 300mm wide by 600mm high) supporting a timber floor with internal short posts nominally embedded 200 to 300mm into the ground TC3 = stiff / robust foundation system - either a 400mm thick waffle slab or timber floor with deeper joists – such that any differential settlement from liquefaction results in planar (i.e. flexure) movement only. Policy dependent. In NZ replacement policies are “as good as new” means typically > 50mm of differential settlement results in requirement to relevel. The repair costs depending on the type of foundation system used. The building loss model has to be locally adapted for local construction typology and also policy Based on building damage repair costs obtained from buildings affected by the CES TC3

The Building Loss Model Ground damage Foundation damage Financial loss Shaking A different set of curves for each area due to: Soil composition Soil density Depth to groundwater Spatial variability Based on building differential settlement survey data obtained from buildings affected by the CES Based on building damage repair costs obtained from buildings affected by the CES

Model outputs for a given MW and PGA 15th percentile 50th percentile 85th percentile M7; 0.3g M7; 0.7g

The Liquefaction Module Framework Ground damage Foundation damage Financial loss Shaking Pipe damage ?

ADVANCED ANALYSIS: 55 Christchurch Sites 16

Representative Soil Profiles YY1 profile NN2 profile 17

Numerical Models 18

Effective Stress Analyses (1/2) Acceleration TH EPWP TH 19

Effective Stress Analyses (2/2) 20

OUTPUT Simplified analysis (conventional engineering tool) Advanced analysis (top-end research / eng. Tool) LIQ damage maps (LSN, LPI, etc.) - indicators of liquefaction-induced damage to land LIQ-induced damage to buildings and infrastructure, in generic terms)  through ‘vulnerability/fragility relationships AF-induced damage relative to CES Acc. TH, response spectra, Detailed soil and site response (in absolute terms and relative to CES) Dynamic animations (disp. & PWP)  an extension to FP1 GM simulations LSN – damage maps 21