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.

Amplified Seismic Loads in Steel Moment Frames

2016 ◽  
Vol 847 ◽  
pp. 222-232
Author(s):  
Bora Aksar ◽  
Selcuk Dogru ◽  
Bulent Akbas ◽  
Jay Shen ◽  
Onur Seker ◽  
...  
Keyword(s):  
Lateral Displacement ◽  
Ground Motions ◽  
Time History ◽  
Load Level ◽  
Steel Buildings ◽  
Moment Frames ◽  
Axial Loads ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Moment Resisting

This study focuses on exploring the seismic axial loads for columns in steel moment resisting frames (SMRFs) under strong ground motions. For this purpose, the increases in axial loads are investigated at the maximum lateral load level and the corresponding lateral displacement. The results are presented in terms of maximum amplification factors (Ω0) of all frame columns under the selected ground motions and axial load-moment levels in columns. four typical steel moment resisting frames representing typical low, medium and high rise steel buildings are designed based on the seismic design requirement in ASCE 7-10 and AISC 341-10 . An ensemble of ground motions range from moderate to severe are selected to identify the seismic response of each frames. Two sets of ground motions corresponding to 10% and 2% probability of exceedance are used in nonlinear dynamic time history analyses.

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.

Application of Buckling-Restrained Braces in the Seismic Design of a Thermal Power Plant in China

2018 ◽  
Vol 763 ◽  
pp. 1017-1024 ◽  
Author(s):  
Mario Aguaguiña ◽  
Ying Zhou ◽  
Shun Ming Gong ◽  
Zhi Qing Fang
Keyword(s):  
Power Plant ◽  
Seismic Design ◽  
Thermal Power Plant ◽  
Response Spectrum ◽  
Thermal Power ◽  
Time History ◽  
Dissipated Energy ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
Buckling Restrained Braces

This paper presents the use of buckling-restrained braces (BRBs) in the design of the main building of a thermal power plant as an alternative for the construction of such kind of large industrial facilities. The project is located in Suqian, Jiangsu Province, a region of high seismic demand (Intensity 8) in China. The main lateral force resisting system used for the structure of this project is composed of a combination of conventional concentrically braced frames (CBFs) and buckling-restrained braced frames (BRBFs). The paper explores the seismic design and performance assessment of this industrial steel building according to the provisions of the Chinese code. Response spectrum analysis and time-history analysis were conducted under two levels of seismic hazard: minor earthquake (63.2%/50 years) and major earthquake (2%/50 years). Results indicate that BRBs effectively helped to control lateral deformation and dissipated energy in stable manner, making the structure composed of CBFs and BRBFs to show the seismic performance as intended by the code.

scholarly journals Seismic Behavior of Concentrically Braced Steel Frames with Out-of-Plane Offset Irregularity

2017 ◽  
Vol 11 (1) ◽  
pp. 485-495 ◽  
Author(s):  
Amin Mohebkhah ◽  
Marzieh Akefi
Keyword(s):  
Seismic Design ◽  
Seismic Behavior ◽  
Steel Frames ◽  
Design Parameters ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
Overstrength Factor ◽  
Concentrically Braced ◽  
Out Of Plane ◽  
Story Drift

Braced steel frames are sometimes designed with out-of-plane shifted bracing members on the first story due to architectural or functional considerations. Such frames are classified and designated as frames having the Type-4 horizontal structural irregularity entitled “frames with out-of-plane offset irregularity” as per theMinimum Design Loads for Building and Other Structures(ASCE 7-10). The purpose of this study is to investigate the nonlinear seismic behavior of ordinary steel concentrically braced frames with out-of-plane offset irregularity and evaluate their seismic design parameters. To this end, two 3-story and 6-story three-dimensional ordinary concentrically braced frames (OCBFs) with and without out-of-plane offset of one of the vertical elements on the first story were considered (i.e. irregular and regular configurations). The seismic design parameters considered in this study includes: frame overall overstrength factor, column overstrength factor and the inelastic dynamic inter-story drift demands. Nonlinear time-history dynamic analysis of the frames showed that overall overstrength factor of the low- and mid-rise irregular frames studied in this research is lower than that of the regular ones. Moreover, it was found that theSeismic Provisionsprescribed overstrength factor (i.e. Ωo=2.0) to amplify columns axial seismic forces in OCBFs is not conservative for the studied regular frames’ columns as well as the columns in the vicinity of the shifted bracing members on the first story of the irregular frames. Also, it was shown that the studied low- and mid-rise regular and irregular concentrically braced frames experience greater inter-story drift demands than predicted by the amplified elastic analysis proposed in the codes.

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.

Seismic evaluation of single-storey steel buildings

1999 ◽  
Vol 26 (4) ◽  
pp. 379-394 ◽  
Author(s):  
M S Medhekar ◽  
DJL Kennedy
Keyword(s):  
Seismic Performance ◽  
Response Spectrum ◽  
Time History ◽  
Analytical Models ◽  
Steel Buildings ◽  
Concentrically Braced Frames ◽  
Braced Frame ◽  
Seismic Zones ◽  
Concentrically Braced Frame ◽  
Concentrically Braced

The seismic performance of single-storey steel buildings, with concentrically braced frames and a roof diaphragm that acts structurally, is evaluated. The buildings are designed in accordance with the National Building Code of Canada 1995 and CSA Standard S16.1-94 for five seismic zones in western Canada with seismicities ranging from low to high. Only frames designed with a force modification factor of 1.5 are considered. Analytical models of the building are developed, which consider the nonlinear seismic behaviour of the concentrically braced frame, the strength and stiffness contributions of the cladding, and the flexibility, strength, and distributed mass of the roof diaphragm. The seismic response of the models is assessed by means of a linear static analysis, a response spectrum analysis, a nonlinear static or "pushover" analysis, and nonlinear dynamic time history analyses. The results indicate that current design procedures provide a reasonable estimate of the drift and brace ductility demand, but do not ensure that yielding is restricted to the braces. Moreover, in moderate and high seismic zones, the roof diaphragm responds inelastically and brace connections are overloaded. Recommendations are made to improve the seismic performance of such buildings.Key words: analyses, concentrically braced frame, dynamic, earthquake, flexible diaphragm, low-rise, nonlinear, seismic design, steel.

Sign in / Sign up

Export Citation Format

Share Document