oq-gem

Glossary for gem taxonomy

Authors: Luke Allen, Andrew Charleson, Svetlana Brzev, and Charles Scawthorn

This online Glossary explains around 400 terms contained in the GEM Building Taxonomy v 2.0 and nearly 700 images.

The terms have been listed in alphabetical and numerical order. Text description of each term is accompanied by illustrations (photos and/or drawings) where possible.

We welcome contributions in the form of photographs or images, illustrating glossary terms. If you have any questions you can also contact us at buildingtaxonomy@globalquakemodel.org


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Non-ductile [DNO]

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Steel members and steel reinforcing are not designed nor constructed to undergo plastic deformation before failure under earthquake loads. In the event of over-load during an earthquake structural members are expected to suffer brittle failure. For example, moment frames with weak columns and strong beams are non-ductile because once the columns are damaged they usually are unable to resist gravity loads.  Reinforced concrete frames will also be classified as non-ductile if beam and column ties have 90 degree rather than 135 degree hooks, and if there is insufficient quantity and spacing of shear reinforcement to prevent shear failure before flexural failure.

Unreinforced masonry buildings usually demonstrate non-ductile performance in earthquakes.

DNO_Colombia_WHE11_1

Details of a non-ductile reinforced concrete frame at critical locations:  beam-column joint, beam and column (L.G. Mejia, Colombia, World Housing Encyclopedia Report 11)

DNO_Colombia_WHE11_2

Widely spaced transverse reinforcement (ties in columns and stirrups in beams) are characteristic for non-ductile reinforced concrete frame; this isometric drawing shows a possible seismic strengthening technique (L.G. Mejia, Colombia, World Housing Encyclopedia Report 11)

DNO_Brzev_Pao_1

Ties in reinforced concrete columns: a) 135 degree hooks (ductile detailing), and b) 90 degree hooks (non-ductile detailing) (Brzev, S. and Pao, J. Reinforced Concrete Design: A Practical Approach, Pearson Learning Solutions, 2012)

DNO_India_Bhuj_Murty_1

DNO_India_Bhuj_Muty_2

Failure of reinforced concrete columns at the ground floor level of a building with the soft storey irregularity in the 2001 Bhuj, India earthquake; the columns were characterized by non-ductile details, such as widely spaced ties and 90 degree hooks in ties (C.V.R. Murty, EERI Reconnaissance Team)

DNO_Taiwan_Chi Chi_EERI_1

Failure at the base of a reinforced concrete column due to 90 degree hooks and widely spaced ties was observed in the 1999 Chi Chi, Taiwan earthquake; use of 90 degree hooks is a feature of non-ductile concrete construction (EERI Reconaissance Team)

DNO_USA_Northridge_BAREP_1

Older steel moment frame buildings were damaged in the 1994 Northridge, California earthquake due to non-ductile beam-column connections and weld fractures (EERI and Bay Area Regional Earthquake Preparedness Project, CAL-OES)

DNO_Haiti_EERI_Lang_1

Damage of a poorly constructed confined masonry building in the 2010 Haiti earthquake; this is considered a non-ductile performance (A. Lang, EERI Reconnaissance Team)

DNO_Algeria_Brzev_1

Unreinforced masonry buildings often show non-ductile performance and suffer damage in major earthquakes, such as the 2003 Boumerdes, Algeria earthquake (S. Brzev)