QuakeCore Alpine Fault case study Thurst Area: Flagship 4 – Next Generation Infrastructure Project title: Performance of traditional versus low-damage floor systems in an AF scenario P.I. Tim Sullivan A.I. Ken Elwood

Background + + + Next Generation Infrastructure: A number of new construction technologies and details have been emerging over the past decade (or more for some technologies such as base isolation) in an effort to achieve low-damage building solutions. The uptake of these technologies has been reasonably slow and hence, Flagship 4 is exploring the potential benefits of using loss assessment to motivate the use of low-damage construction solutions. Existing fragility functions used for flooring systems in such procedures do not appear to be NZ specific. P[DS|EDP] 1.0 DS EDP Repair Cost (per unit area/vol) Extent of repairs DS2 DS1 Partition Damage Repair Re-routing wiring Beams Columns Partitions Glazing Ceiling Electrical HVAC + + + Component Inventory Damage Fragility Cost Distribution Damage Correlation

Background - continued Kaikoura Earthquake: Highlighted vulnerability of commercial buildings in Wellington. In particular, emphasized vulnerability of pre-cast flooring systems within moment resisting frames (that are prone to elongate in intense earthquakes). Important since precast floors are a predominant type of flooring system in NZ. Previous research into precast floor systems: Previous research (e.g. Matthews 2004, Fenwick et al. 2010) had highlighted the vulnerability of precast floor systems and identified reasons for this. It does not appear, however, that work has been done to identify fragility functions for such flooring systems. NZSEE assessment guidelines: The NZSEE recently published assessment guidelines that assist practitioners identify the strength and deformation capacity of a structure. Within these guidelines, simplified relationships are required to relate the deformation capacity of an element (such as a precast flooring unit) to the deformation capacity of the structural system. Pre-cast flooring

Project Aims Use the AF scenario to demonstrate: The difference (increase) in losses when using more realistic fragilities for NZ concrete commercial buildings compared with fragility curves based on US studies; and The difference (decrease) in losses (relative to estimate of losses in “a”) when using fragilities representative of floors in low-damage building systems for 5-10% of the building inventory (assumed uptake of low damage systems in 10-15 years).

Project Methodology Collect data relevant to fragility of precast floor systems from past testing. [UC postdoc] Collect data relevant to fragility of precast floor systems from Christchurch and Wellington buildings. [UA QuakeCoRE scholar] Collect data relevant to fragility of floors in low-damage building systems. [UC Masters student] Develop mechanics-based relationships between floor fragility and building system fragility. [UC Masters student and UC postdoc] Through discussions at QuakeCoRE workshop on low damage systems, estimate: - percent buildings to be replaced by low damage systems in next 10 years - expected improvement in fragility curves for typical low damage systems.

Project Outputs PART A - Discipline specific: Fragility of precast concrete floors typical of existing NZ buildings will be developed based on test data from UC and UA, in addition to data from Kaikoura earthquake. Fragility of floors in low-damage building systems through examination of existing test data and analytical studies. Means of relating floor fragility functions to building system fragility. PART B – Products provided for hazard-to-impact calculator: New building fragilities from Part A will be provided to Integration team for assessment of expected damage states and losses.

PART A – 1: Fragility of precast concrete floors typical of existing NZ buildings will be developed based on test data from UC and UA, in addition to data from Kaikoura earthquake. Matthews 2004

Fenwick et al. 2010

Fenwick et al. 2010 Various details reported – old and new. Impact on vulnerability/fragility?

Fenwick et al. 2010

Fenwick et al. 2010 Various details reported – old and new. Impact on vulnerability/fragility?

Fenwick et al. 2010 Various details reported – old and new. Impact on vulnerability/fragility? P[DS|EDP] 1.0 DS Drift Floor Fragility Curves

Loss assessment of various case study buildings Cross-Over with F4 Loss Assessment Project Loss assessment of various case study buildings Building type and geometry 4 storey residential 4 storey office building 12 storey office building 40 m (4-s) or 48 m (12-s) 24 m (4-s) or 32 m (12-s) Plan view (Structural layout not fixed) 1.8 m 2.7 m 0.7 m 0.2 m Floor slab Structural beam Ceiling Services (i.e. HVAC, pipework) Bracing 4.0 m 3.6 m Front Elevation (Structural layout not fixed) Floor level cross section

F4 Case study buildings Building locations NZS1170.5:2004, Section 3.1 Building locations Auckland, Christchurch, and Wellington NZS3101:2006, Table 2.5

Case study buildings Building Components Fragility? Flooring Retrieved from www.stahlton.co.nz on 26/02/2017) Building Components Flooring Fragility? Retrieved from www.comflor.co.nz on 26/02/2017) To be defined and will permit loss assessment comparisons of different building systems Retrieved from www.bancrete.com on 26/02/2017) Composite flooring: Steel buildings if not exposed Double Tee flooring: Reinforced concrete buildings Steel buildings if exposed

System displacement capacity? PART A – 3: Means of relating floor fragility functions to building system fragility. The final specific research output will be to provide means of relating local drift capacity of flooring system with global deformation capacity of building. Such relationships should be useful for seismic assessment of single buildings (NZSEE approach) or building stocks (using simplified displacement-based building fragility functions). System displacement capacity? Hn Height (hi) . Local damage to flooring h3 h2 h1 qc Lateral displacement

PART B – 1: New building fragilities from Part A will be provided to Integration team for assessment of expected damage states and losses.. Via collaboration within F4, building fragilities expected to be provided for: 4 & 12 storey office buildings – different fragilities for traditional structural systems and modern/low-damage systems 4 storey residential building – again different fragilities for traditional structural systems and modern/low-damage systems.