scholarly journals Damage to Steel Buildings Observed after the 2011 Tohoku-Oki Earthquake

2013 ◽  
Vol 29 (1_suppl) ◽  
pp. 219-243 ◽  
Author(s):  
Taichiro Okazaki ◽  
Dimitrios G. Lignos ◽  
Mitsumasa Midorikawa ◽  
James M. Ricles ◽  
Jay Love
Keyword(s):  
Seismic Design ◽  
Tsunami Wave ◽  
Structural Performance ◽  
Building Structures ◽  
Braced Frames ◽  
Steel Buildings ◽  
Ground Acceleration ◽  
The City ◽  
Insight Into ◽  
Foundation Failure

A joint U.S.–Japan reconnaissance team examined the damage to steel building structures caused by the 2011 Tohoku-oki earthquake. In the city of Sendai, where the peak horizontal ground acceleration exceeded 1 g, the majority of steel buildings performed well. Buildings that used older cladding systems for external finish sustained damage to their claddings even if their structural performance was excellent. Damage to a few braced frames offer insight into the seismic design of bracing connections. In areas attacked by the violent tsunami, many steel buildings stood upright after the tsunami subsided, although these buildings lost much of their external and internal finishes along with their contents. These steel buildings did not provide safe shelter for tsunami evacuation when the building submerged under the tsunami wave. A number of buildings suffered foundation failure, which was likely caused by scouring or liquefaction or a combination of multiple effects.

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

2014 ◽  
Vol 30 (4) ◽  
pp. 1683-1709 ◽  
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.

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

1996 ◽  
Vol 23 (3) ◽  
pp. 727-756 ◽  
Author(s):  
Robert Tremblay ◽  
Andre Filiatrault ◽  
Michel Bruneau ◽  
Masayoshi Nakashima ◽  
Helmut G. L. Prion ◽  
...  
Keyword(s):  
Seismic Design ◽  
Steel Structures ◽  
Structural Systems ◽  
Braced Frames ◽  
Steel Buildings ◽  
Concentrically Braced Frames ◽  
Framed Structures ◽  
Concentrically Braced ◽  
Moment Resisting ◽  
Column Bases

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.

Structural performance of buildings during the 30 November 2018 M7.1 Anchorage, Alaska earthquake

2021 ◽  
pp. 875529302110435
Author(s):  
Wael M Hassan ◽  
Janise Rodgers ◽  
Christopher Motter ◽  
John Thornley
Keyword(s):  
Structural Damage ◽  
Seismic Vulnerability ◽  
The United States ◽  
Structural Performance ◽  
Single Family ◽  
Steel Buildings ◽  
Test Bed ◽  
Building Stock ◽  
Ground Acceleration ◽  
Nonstructural Components

Southcentral Alaska, the most populous region in Alaska, was violently shaken by a Mw 7.1 earthquake on 30 November 2018 at 8:29 am Alaska Standard Time. This was the largest magnitude earthquake in the United States close to a population center in over 50 years. The earthquake was 46 km deep, and the epicenter was 12 km north of Anchorage and 19 km west of Eagle River. The event affected some 400,000 residents, causing widespread damage in highways, nonstructural components, non-engineered and older buildings, and structures on poorly compacted fills. A few isolated serious injuries and partial collapses took place. Minor structural damage to code-conforming buildings was observed. A significant percentage of the structural damage was due to geotechnical failures. Building stock diversity allows use of the region as a large test bed to observe how local building practices affected earthquake damage levels. The prevailing peak ground acceleration (PGA) was 0.2–0.32 g, causing shaking intensity at most sites of 50%–60% of the ASCE 7-16 design basis earthquake acceleration. Thus, the seismic vulnerability of building stock in the region was not truly tested. Reinforced concrete buildings had minor structural damage, except in a few cases of shear wall and transfer girder shear cracking. Fiber-reinforced polymer (FRP)-retrofitted buildings performed satisfactorily. Concrete-masonry-unit (CMU) masonry buildings experienced serious structural damage in many cases, including relatively newer buildings. The earthquake caused widespread structural damage in non-engineered buildings (primarily wood and CMU masonry) that exist widely in the region, especially in Eagle River. Of these, non-engineered single-family wood buildings had the heaviest structural damage. No structural damage could be observed in steel buildings. The aftershock sequence, which included 7 M5+ and 50 M4+ events, exacerbated structural damage in all types of buildings. The present study is based on the EERI field reconnaissance mission conducted by the authors following the earthquake. Based on the observed damage and structural performance, seismic risk mitigation recommendations are suggested.

A Discussion on some Key Issues for Seismic Design of Concentrically Braced Frames According to Canadian and Chinese Codes

2010 ◽  
Vol 163-167 ◽  
pp. 211-221
Author(s):  
Wen Yuan Zhang ◽  
Constantin Christopoulos
Keyword(s):  
Seismic Design ◽  
Braced Frames ◽  
Capacity Design ◽  
Concentrically Braced Frames ◽  
Main Design ◽  
Seismic Force ◽  
Concentrically Braced ◽  
Key Issues ◽  
Design Requirements ◽  
Insight Into

To gain further insight into the seismic design of concentrically braced frames as defined by the Canadian and Chinese codes, a comparison of the main design requirements contained in each code is carried out in this paper. The comparison emphasizes on the differences existing in these two code provisions, and the reasons behind them. The issues that are examined include the seismic force resisting systems for braced frames, the height restrictions, the force transferred to the beams in chevron configurations, the slenderness ratios of the bracing members, the width-to-thickness ratios of the brace sections, and the influence of brace connections on the columns. Some additional issues that still remain undefined on the seismic response of these systems and some proposals for further studies are also discussed. It is concluded through this comparison that a number of modifications are still required in order to fully implement a capacity design approach of these systems in both codes.

Assessment of Performance-Based Seismic Design Methods in ASCE 41 for New Steel Buildings: Special Moment Frames

2018 ◽  
Vol 34 (3) ◽  
pp. 977-999 ◽  
Author(s):  
John Harris ◽  
Matthew Speicher
Keyword(s):  
Seismic Design ◽  
Performance Metrics ◽  
Structural Performance ◽  
Steel Buildings ◽  
Moment Frames ◽  
Component Level ◽  
Existing Building ◽  
Special Moment Frames ◽  
Steel Building ◽  
Performance Based Seismic Design

This paper presents the results of a study investigating the correlation between the anticipated seismic performance of an ASCE 7 code-compliant steel building with special moment frames and its predicted performance as quantified using ASCE 41 analysis procedures and structural performance metrics. Analytical results based on component-level performances at the collapse prevention structural performance level indicate that special moment frames designed in accordance with ASCE 7, and its referenced standards, have difficulty satisfying the acceptance criteria in ASCE 41 for an existing building intended to be equivalent to a new building.

scholarly journals Special Moment Resistant Steel Buildings

2021 ◽  
pp. 444-448
Author(s):  
Deepan Dev B ◽  
Dr V Selvan
Keyword(s):  
Pushover Analysis ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Building Structures ◽  
Braced Frames ◽  
Steel Buildings ◽  
Braced Frame ◽  
Moment Resisting ◽  
Frame Systems ◽  
Nonlinear Time History

The seismic response of special moment-resisting frames (SMRF), buckling restrained braced (BRB) frames and self-centering energy dissipating (SCED) braced frames is compared when used in building structures many stories in height. The study involves pushover analysis as well as 2D and 3D nonlinear time history analysis for two ground motion hazard levels. The SCED and BRB braced frames generally experienced similar peak interstory drifts. The SMRF system had larger interstory drifts than both braced frames, especially for the shortest structures. The SCED system exhibited a more uniform distribution of the drift demand along the building height and was less prone to the biasing of the response in one direction due to P-Delta effects. The SCED frames also had significantly smaller residual lateral deformations. The two braced frame systems experienced similar interstory drift demand when used in torsional irregular structures.

Accounting for overstrength in seismic design of steel structures

1998 ◽  
Vol 25 (1) ◽  
pp. 1-15 ◽  
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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