Seismic design of steel buildings: lessons from the 1995 Hyogo-ken Nanbu earthquake

Past and current seismic design provisions for steel structures in Japan are presented and compared with Canadian requirements. The performance of steel framed structures during the January 17, 1995, Hyogo-ken Nanbu earthquake is described. Numerous failures and examples of inadequate behaviour could be observed in buildings of various ages, sizes, and heights, and braced with different structural systems. In moment resisting frames, the damage included failures of beams, columns, beam-to-column connections, and column bases. Fracture of bracing members or their connections was found in concentrically braced frames. The adequacy of the current Canadian seismic design provisions is examined in view of the observations made. Key words: earthquake, seismic design, steel structures.

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Code-Oriented Methodology for the Seismic Design of Regular Steel Moment-Resisting Braced Frames

Earthquake Spectra ◽

10.1193/032012eqs100m ◽

2014 ◽

Vol 30 (4) ◽

pp. 1683-1709 ◽

Cited By ~ 11

Author(s):

Edgar Tapia-Hernández ◽

Arturo Tena-Colunga

Keyword(s):

Seismic Design ◽

Time History ◽

Federal District ◽

Design Parameters ◽

Braced Frames ◽

Steel Buildings ◽

Moment Frames ◽

Concentrically Braced Frames ◽

Design Spectrum ◽

Moment Resisting

In order to help improve the seismic design of regular steel buildings structured with ductile moment-resisting concentrically braced frames (MRCBFs) using the general design methodology of Mexico's Federal District Code (MFDC-04), suitable design parameters were first assessed using the results of pushover analyses of 13 regular MRCBFs. In order to insure collapse mechanisms consistent with the assumptions implicit in a code-based design (strong-column/weak-beam/weaker-brace), it is proposed to relate the minimum strength ratio for the resisting columns of the moment frames and the bracing system. Improved equations are proposed for a more realistic assessment of ductility and overstrength factors. In a second stage, the effectiveness of the improved methodology was assessed with the design of six regular steel buildings with MRCBFs. Buildings were evaluated by performing both pushover and nonlinear time-history analyses under ten selected artificial ground motions related to the corresponding design spectrum.

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Assessment of First Generation Performance-Based Seismic Design Methods for New Steel Buildings, Volume 2: Special Concentrically Braced Frames

10.6028/nist.tn.1863-2 ◽

2015 ◽

Cited By ~ 2

Author(s):

John L. Harris III ◽

Matthew S. Speicher

Keyword(s):

Seismic Design ◽

First Generation ◽

Design Methods ◽

Braced Frames ◽

Steel Buildings ◽

Concentrically Braced Frames ◽

Concentrically Braced ◽

Performance Based Seismic Design

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Steel structures damage from the Christchurch earthquake series of 2010 and 2011

Bulletin of the New Zealand Society for Earthquake Engineering ◽

10.5459/bnzsee.44.4.297-318 ◽

2011 ◽

Vol 44 (4) ◽

pp. 297-318 ◽

Cited By ~ 34

Author(s):

Charles Clifton ◽

Michel Bruneau ◽

Greg MacRae ◽

Roberto Leon ◽

Alistair Fussell

Keyword(s):

Steel Structures ◽

Braced Frames ◽

Concentrically Braced Frames ◽

Eccentrically Braced Frames ◽

Satisfactory Performance ◽

Concentrically Braced ◽

Earthquake Series ◽

Moment Resisting ◽

Industrial Storage ◽

Storage Racks

This paper presents preliminary field observations on the performance of selected steel structures in Christchurch during the earthquake series of 2010 to 2011. This comprises 6 damaging earthquakes, on 4 September and 26 December 2010, February 22, June 6 and two on June 13, 2011. Most notable of these was the 4 September event, at Ms7.1 and MM7 (MM as observed in the Christchurch CBD) and most intense was the 22 February event at Ms6.3 and MM9-10 within the CBD. Focus is on performance of concentrically braced frames, eccentrically braced frames, moment resisting frames and industrial storage racks. With a few notable exceptions, steel structures performed well during this earthquake series, to the extent that inelastic deformations were less than what would have been expected given the severity of the recorded strong motions. Some hypotheses are formulated to explain this satisfactory performance.

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Performance of steel structures during the 1994 Northridge earthquake

Canadian Journal of Civil Engineering ◽

10.1139/l95-046 ◽

1995 ◽

Vol 22 (2) ◽

pp. 338-360 ◽

Cited By ~ 113

Author(s):

Robert Tremblay ◽

André Filiatrault ◽

Peter Timler ◽

Michel Bruneau

Keyword(s):

Current Knowledge ◽

Steel Frames ◽

Steel Structures ◽

Northridge Earthquake ◽

Braced Frames ◽

Concentrically Braced Frames ◽

Load Paths ◽

Concentrically Braced ◽

Moment Resisting ◽

Observed Damage

The performance of concentrically braced steel frames and moment resisting steel frames during the January 17, 1994, Northridge, California, earthquake is examined. Most of the observations made during the reconnaissance visits confirmed the current knowledge on the inelastic response of these structural systems. This permits the anticipation of proper seismic behavior for buildings designed according to the seismic provisions that have been recently introduced in the Canadian building code and standard for steel structures. In some cases, however, the observed damage raised concerns that should be addressed in future investigations or next editions of these codes. Preventing potentially hazardous nonstructural damage, avoiding premature nonductile failures anywhere along the lateral load paths, limiting structural and nonstructural damage due to brace buckling, and accounting for the vertical ground motion are among those issues. Key words: earthquake, seismic, steel, concentrically braced frames, moment resisting frames, weld.

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On California Structural Steel Seismic Design

Earthquake Spectra ◽

10.1193/1.1585407 ◽

1986 ◽

Vol 2 (4) ◽

pp. 703-727 ◽

Cited By ~ 3

Author(s):

Egor P. Popov

Keyword(s):

Structural Steel ◽

Seismic Design ◽

Steel Frames ◽

Steel Structures ◽

Concentrically Braced Frames ◽

Concentrically Braced ◽

Moment Resisting ◽

The Usa ◽

Major Attention ◽

Eccentric Bracing

A number of new code developments, largely initiated in California, are taking place in the USA for the seismic design of steel structures. The principal ones are reviewed and commented upon in the paper. Key experimental support for some of the changes is indicated. Major attention is directed to the three main types of steel construction: moment-resisting frames, concentrically braced steel frames, and, the relatively new method for seismic design, eccentric bracing. Some of the proposed and possible practical improvements in moment-resisting connections are given; the reasons for some concern over the use of concentrically braced frames for severe seismic applications are discussed; and a brief overview on the application of eccentrically braced steel frames is presented. The paper concludes with a few remarks on future trends and needs in structural steel seismic design.

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Accounting for overstrength in seismic design of steel structures

Canadian Journal of Civil Engineering ◽

10.1139/l97-045 ◽

1998 ◽

Vol 25 (1) ◽

pp. 1-15 ◽

Cited By ~ 18

Author(s):

M A Rahgozar ◽

J L Humar

Keyword(s):

Seismic Design ◽

Slenderness Ratio ◽

Steel Structures ◽

Building Structures ◽

Braced Frames ◽

Concentrically Braced Frames ◽

Moment Resisting Frames ◽

Moment Resisting ◽

Design Loads ◽

Reserve Strength

Observations during many earthquakes have shown that building structures are able to sustain without damage earthquake forces considerably larger than those they were designed for. This is explained by the presence in such structures of significant reserve strength not accounted for in design. Relying on such overstrength, many seismic codes permit a reduction in design loads. The possible sources of reserve strength are outlined in this paper, and it is reasoned that a more rational basis for design would be to account for such sources in assessing the capacity rather than in reducing the design loads. As an exception, one possible source of reserve strength, the redistribution of internal forces, may be used in scaling down the design forces. This is because such scaling allows the determination of design forces through an elastic analysis rather than through a limit analysis. To assess the extent of reserve strength attributable to redistribution, steel building structures having moment-resisting frames or concentrically braced frames and from 2 to 30 storeys in height are analyzed for their response to lateral loading. A static nonlinear push-over analysis is used in which the gravity loads are held constant while the earthquake forces are gradually increased until a mechanism forms or the specified limit on interstorey drift is exceeded. It is noted that in moment-resisting frames the reserve strength reduces with an increase in the number of storeys as well as in the level of design earthquake forces. The P→Δ effect causes a further reduction. In structures having braced frames the main parameter controlling the reserve strength is the slenderness ratio of the bracing members. In these structures, reserve strength is almost independent of both the height of the structure and the effect of building sway. Key words: seismic design, overstrength factor, reserve strength owing to redistribution, steel moment-resisting frames, steel-braced frames, push-over analysis.

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On California structural steel seismic design

Bulletin of the New Zealand Society for Earthquake Engineering ◽

10.5459/bnzsee.20.1.7-21 ◽

1987 ◽

Vol 20 (1) ◽

pp. 7-21

Author(s):

Egor P. Popov

Keyword(s):

Structural Steel ◽

Seismic Design ◽

Steel Frames ◽

Steel Structures ◽

Concentrically Braced Frames ◽

Concentrically Braced ◽

Moment Resisting ◽

The Usa ◽

Major Attention ◽

Eccentric Bracing

A number of new code developments, largely initiated in California, are taking place in the USA for the seismic design of steel structures.  The principal ones are reviewed and commented upon in the paper. Key experimental support for some of the changes is indicated. Major attention is directed to the three main types of steel construction: moment resisting frames, concentrically braced steel frames, and, the relatively new method for seismic design, eccentric bracing. Some of the proposed and possible practical improvements in moment-resisting connections are given: the reasons for some concern over the use of concentrically braced frames for severe seismic applications are discussed; and a brief overview on the application of eccentrically braced steel frames is presented. The paper concludes with a few remarks on future trends and needs in structural steel seismic design.

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