Forensic analysis of Eccentrically Braced Frame Fracture during the 2/22/11 Christchurch, NZ

EarthquakeKyle Marshall, David Grilli, Graduate Student Researchers, UC DavisAmit Kanvinde, Associate Professor, UC Davis

The issue – first observed field fractures worldwide in an EBFParking garage, Christchurch Hospital, Christchurch, NZ

Data collected/synthesized

Experiments and simulations

Preliminary findings

Sponsor: National Science Foundation, Industry and New Zealand Partners: Geoff Bomba, Forell Elsesser Engineers, San Francisco, CA; Chris Allington, Holmes Consulting, Christchurch, NZ,

- Fractured components obtained- 3-d scans conducted to regenerate as-

built geometrical features- Building drawings, site ground

motions obtained - Nonlinear time history simulations

conducted to obtain link deformations

- Coupons extracted from components- Charpy V Notch, Stress Strain and

Fracture Mechanics Tests conducted- Material properties obtained from

these tests used in conjunction with deformation histories from frame simulations to conduct detailed fracture mechanics finite element simulations of components

- Steel meets toughness requirements- Demands are not entirely unexpected, although severe- Fracture is likely due to poor detailing- More stringent detailing guidelines and enforcement

would prevent such failure in the United States and elsewhere

Continuum FEM simulation of

fractured region