Damage to concrete structures due to the 1994 Northridge earthquake

1995 ◽  
Vol 22 (2) ◽  
pp. 361-377 ◽  
Author(s):  
Denis Mitchell ◽  
Ronald H. DeVall ◽  
Murat Saatcioglu ◽  
Robert Simpson ◽  
René Tinawi ◽  
...  
Keyword(s):  
Seismic Design ◽  
Precast Concrete ◽  
Concrete Structures ◽  
Shear Walls ◽  
Northridge Earthquake ◽  
Short Columns ◽  
Gravity Load ◽  
Current Design ◽  
Design Earthquake ◽  
1994 Northridge Earthquake

Observations on damage to concrete structures, due to the 1994 Northridge earthquake, are reported from a Canadian code perspective. Most of the damaged structures were older, nonductile, structures that do not conform to current design and detailing requirements. Concern is expressed about the seismic hazard of older Canadian structures having similar deficiencies. A significant number of parking structures suffered extensive damage and a number of precast concrete parking structures collapsed. Deficiencies in these structures include lack of proper diaphragm connections, a mix of gravity load columns with ductile framing, inappropriate number and distribution of shear walls, torsional effects caused by ramps, and the creation of short columns due to geometric features. This earthquake also demonstrated the deficiencies in connections of pre-1973 tilt-up structures. Key words: seismic design, earthquake, Northridge, structures, codes, concrete, precast concrete.

Seismic strengthening of pin-connected precast concrete structures with external shear walls and diaphragms

PCI Journal ◽  
2009 ◽  
Vol 54 (1) ◽  
pp. 88-99 ◽  
Author(s):  
Hasan Kaplan ◽  
Halil Nohutcu ◽  
Nihat Çetinkaya ◽  
Salih Yılmaz ◽  
Hasan Gönen ◽  
...  
Keyword(s):  
Precast Concrete ◽  
Concrete Structures ◽  
Shear Walls ◽  
Seismic Strengthening

Seismic weaknesses of some residential wood framed buildings: confirmations from the 1994 Northridge earthquake

1995 ◽  
Vol 22 (2) ◽  
pp. 403-414 ◽  
Author(s):  
André Filiatrault ◽  
Chris K. A. Stieda
Keyword(s):  
Seismic Design ◽  
Earthquake Engineering ◽  
Residential Construction ◽  
Northridge Earthquake ◽  
Wood Structures ◽  
Canadian Association ◽  
Epicentral Region ◽  
The U.S ◽  
Construction Practice ◽  
1994 Northridge Earthquake

As part of the reconnaissance team of the Canadian Association for Earthquake Engineering (CAEE), the authors visited the epicentral region of the January 17, 1994, Northridge earthquake. This paper reviews the various potential weaknesses of some residential timber framed buildings. The damage observed during the Northridge earthquake as a result of these weaknesses is used to illustrate the need to introduce engineering concepts in the seismic design and retrofit of residential wood structures. Typical mitigation procedures to strengthen and increase the earthquake safety of wood buildings are discussed. Recognizing the close similarity between residential construction practice in Canada and the U.S., the information presented is topical for Canadian engineers, architects and owners. Key words: earthquake, seismic, timber, wood framed buildings.

scholarly journals Influence of shear flexibility in structural shear walls on pushover analysis

Mechanika ◽  
2020 ◽  
Vol 26 (2) ◽  
pp. 146-152
Author(s):  
Mário Rui Tiago Arruda ◽  
Bruno Lopes ◽  
Mário Ferreira ◽  
Tadas Zingaila
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Seismic Design ◽  
Pushover Analysis ◽  
Concrete Structures ◽  
Shear Walls ◽  
Reinforced Concrete Structures ◽  
Structural Walls ◽  
Shell Elements ◽  
N2 Method

The aim of this work is to show the main differences which exist, taking in to account the influence of the type of finite element used, when performing pushover analysis of reinforced concrete structures. The non-linear analysis was performed using FE software SAP2000, and the results were extracted from models including Frame and Shell elements, respectively. Several reinforced concrete structures were modelled with Frame elements and Shell elements, which will be further presented. Therefore, it was possible to validate the results obtained from the analysis, also to identify certain restrictions according to the type of finite element used in the modelling of the resistant walls. In the first phase, three isolated structural walls were modelled with distinct geometries. The first one presents a rectangular shape, the second – “L” shape and the third one “U” shape. The application of pushover analysis through the different examples presented in this document, intends to validate the results obtained for the Shell elements. Subsequently, the same kind of analysis was performed on a building. These examples intend to show that the performance of ductility is strongly dependent from the type of element, which is not taken into account in the pushover analysis nowadays. N2 method was applied to all examples, in order to understand the differences in the structures seismic design, according to the type of element used in the modelling. The results are compared, and the differences are identified. As well as, the limitations of applicability of Shell elements in the modelling of structural walls were determined.

The August 17, 1999, Kocaeli (Turkey) earthquake — damage to structures

2001 ◽  
Vol 28 (4) ◽  
pp. 715-737
Author(s):  
Murat Saatcioglu ◽  
Denis Mitchell ◽  
René Tinawi ◽  
N John Gardner ◽  
Anthony G Gillies ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Precast Concrete ◽  
Steel Structures ◽  
Masonry Structures ◽  
Industrial Facilities ◽  
New Construction ◽  
Design Earthquake ◽  
Code Provisions ◽  
Construction Practice

The 1975 Turkish code provisions are first reviewed to provide the background for design and detailing of structures prior to the earthquake. The performance of reinforced concrete and masonry structures is described indicating many of the deficiencies in design, detailing, and construction execution. The behaviour of precast concrete structures, steel structures, and industrial facilities is also presented. The provisions of the 1997 Turkish building code are summarized and a description of new construction provides evidence of both excellent and poor construction practice. Some examples of retrofitting of damaged structures soon after the earthquake are also presented.Key words: seismic design, earthquake, Kocaeli, structures, codes, concrete, precast concrete.

Analytical study on seismic force modification factors for cross-laminated timber buildings

2013 ◽  
Vol 40 (9) ◽  
pp. 887-896 ◽  
Author(s):  
Shiling Pei ◽  
Marjan Popovski ◽  
John W. van de Lindt
Keyword(s):  
Seismic Design ◽  
Analytical Study ◽  
Planning Process ◽  
Shear Walls ◽  
Building Performance ◽  
Structural System ◽  
Cross Laminated Timber ◽  
Process Use ◽  
Seismic Force ◽  
Design Earthquake

With two producers in operation and over 20 buildings already constructed or in planning process, use of cross-laminated timber (CLT) is gaining popularity in Canada. Since CLT as a structural system is currently not included in the National Building Code of Canada (NBCC), one of the most important issues are the values for the force modification factors for seismic design of CLT structures when NBCC equivalent static force procedure is used. In this study, a test-calibrated numerical model for CLT shear walls was applied to develop the design resistances for typical CLT wall configurations. An estimation of a possible range of Rd-factors was obtained by developing design variations for three multi-storey CLT apartment buildings. By specifying the desired seismic performance in terms of inter-storey drift, it is concluded that an Rd-factor of 2.0 will likely provide desirable building performance during the design earthquake level event in Vancouver, B.C.

Safety of gravity-load columns in shear wall buildings designed to Canadian standard CSA A23.3

2010 ◽  
Vol 37 (11) ◽  
pp. 1451-1461 ◽  
Author(s):  
Perry Adebar ◽  
Poureya Bazargani ◽  
James Mutrie ◽  
Denis Mitchell
Keyword(s):  
Nonlinear Analysis ◽  
Plastic Hinge ◽  
Shear Walls ◽  
Canadian Standard Association ◽  
Design Rule ◽  
Seismic Demands ◽  
Gravity Load ◽  
Load Carrying ◽  
Bar Buckling ◽  
Design Earthquake

It has been a Canadian code requirement for 25 years to check whether concrete gravity-load columns can tolerate the building deformations due to the design earthquake; but the way this has typically been done using linear analysis significantly underestimates the seismic demands on gravity-load columns. Concern about the safety of gravity-load columns over the plastic hinge height of concrete shear walls, particularly elongated wall-like gravity-load columns, has resulted in new design requirements in Update No. 3 of Canadian Standard Association (CSA) A23.3–04 issued in August 2009. The current paper provides the background to these new requirements. If nonlinear analysis is not done, closely spaced seismic hoops shall be provided in all columns and walls that support gravity loads, and these members shall meet the same limit on maximum compression strain depth as concrete shear walls. The results of nonlinear analyses were used to validate this simple design rule, and to investigate factors that increase seismic demands on gravity-load columns such as diagonal cracking of concrete shear walls, localized damage of columns from cover spalling and bar buckling, and larger first storey heights. Nonlinear analysis has shown that 2.4 m (8 ft) long columns can lose over 50% of their axial load carrying capacity at an inelastic drift ratio of only 1%.

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