Seismic characterization of steel special moment frames subjected to megathrust earthquakes

2020 ◽  
Vol 36 (4) ◽  
pp. 2033-2057
Author(s):  
Miguel Medalla ◽  
Diego Lopez-Garcia ◽  
Farzin Zareian
Keyword(s):  
Seismic Design ◽  
Ground Motions ◽  
Steel Structures ◽  
Moment Frames ◽  
Risk Levels ◽  
Megathrust Earthquakes ◽  
Crustal Earthquakes ◽  
Special Moment Frames ◽  
Seismic Characterization ◽  
Design Requirements

Current seismic design requirements were established considering mainly (almost exclusively) ground motions caused by shallow crustal earthquakes, hence they might lead to different-from-intended risk levels when applied at locations prone to large-magnitude subduction (i.e. megathrust) earthquakes. In this study, the seismic behavior of 40 modern steel special moment frames (SSMFs) subjected to both megathrust and crustal ground motions is evaluated. Three analyses are performed: (1) a hazard-consistent analysis; (2) a comparative collapse risk evaluation; and (3) a performance evaluation following the approach indicated in Federal Emergency Management Agency (FEMA) P695. Results indicate that the collapse probability of mid- and high-rise SSMFs subjected to megathrust ground motions is indeed larger than that under crustal ground motions. Modifications to the current design criteria are then suggested, intended not only for United States but also for countries, such as Ecuador, where the US seismic design requirements for steel structures were adopted and seismic ground motions are actually caused by megathrust earthquakes.

Seismic Performance Evaluation of Intermediate Moment Frames with Reduced Beam Section and Bolted Web Connections

2015 ◽  
Vol 31 (2) ◽  
pp. 895-919 ◽  
Author(s):  
Sang Whan Han ◽  
Ki Hoon Moon ◽  
Seong-Hoon Hwang ◽  
Bozidar Stojadinovic
Keyword(s):  
Seismic Performance ◽  
Seismic Design ◽  
Moment Frames ◽  
Seismic Performance Evaluation ◽  
Reduced Beam Section ◽  
Rotation Capacity ◽  
Special Moment Frames ◽  
Story Drift ◽  
Beam Section ◽  
B Test

A reduced beam section with a bolted web (RBS-B) connection is permitted for use only in intermediate moment frames (IMF) according to the ANSI/AISC 358-05. This is because some RBS-B test specimens failed to achieve 4% total rotation capacity, which is the minimum story drift angle required for special moment frames (SMF). Several studies reported that some RBS-B connections could experience brittle connection fracture during earthquakes, which can also be detrimental to the seismic performance of IMF systems with RBS-B connections. For investigating whether IMFs with RBS-B connections provide a satisfactory seismic performance, this study evaluated the seismic performance of IMFs with pre-qualified RBS-B connections following the ATC-63 procedure. Twenty-four model buildings were designed according to current seismic design provisions. Several IMFs with RBS-B connections do not satisfy the acceptance criteria specified in ATC-63.

scholarly journals Seismic design of steel special moment frames:

2009 ◽  
Author(s):  
Ronald O Hamburger ◽  
Helmut Krawinkler ◽  
James O Malley ◽  
Scott M Adan
Keyword(s):  
Seismic Design ◽  
Moment Frames ◽  
Special Moment Frames

Performance-Based Seismic Design of Pallet-Type Steel Storage Racks

2006 ◽  
Vol 22 (1) ◽  
pp. 47-64 ◽  
Author(s):  
André Filiatrault ◽  
Robert E. Bachman ◽  
Michael G. Mahoney
Keyword(s):  
Seismic Design ◽  
Ground Motions ◽  
Design Procedure ◽  
The United States ◽  
Moment Frames ◽  
Type Steel ◽  
Collapse Prevention ◽  
Moment Resisting ◽  
Performance Based Seismic Design ◽  
Storage Racks

This paper develops a performance-based seismic design procedure for pallet-type steel storage racks located in areas accessible to the public. Performance objectives for racks consistent with current building code procedures in the United States are defined. The paper focuses on collapse prevention of racks in their down-aisle direction under the Maximum Considered Earthquake (MCE) ground motions at the site. The down-aisle lateral load-resisting systems of racks are typically moment frames utilizing special proprietary beam-to-column moment-resisting connections that may result in large lateral displacements when subjected to MCE ground motions. A simple analytical model that captures the seismic behavior of racks in their down-aisle direction is proposed. The model assumes that the beams and columns remain elastic in the down-aisle direction and that all nonlinear behavior occurs in the beam-to-column connections and the moment-resisting connections between the base columns and support concrete slab. Therefore the behavior is based on the effective rotational stiffnesses developed by the beam-to-column connectors and column-to-slab connections that vary significantly with connection rotation. The model is validated against the results of shake-table tests conducted on full-scale racks under several ground-motion intensities. Finally, the model is incorporated in a displacement-based procedure to verify collapse prevention of racks in their down-aisle direction under the MCE.

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.

Seismic design of low- and medium-rise chevron braced steel frames

2000 ◽  
Vol 27 (6) ◽  
pp. 1192-1206 ◽  
Author(s):  
Robert Tremblay ◽  
Nathalie Robert
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Ground Motions ◽  
Steel Structures ◽  
Shear Resistance ◽  
Seismic Loads ◽  
Braced Frames ◽  
Design Procedures ◽  
Reinforced Beams ◽  
Strong Ground

This paper presents two different seismic design approaches for multistorey chevron (inverted V) steel braced frames. The first method complies with current Canadian code provisions in which the beams in the bracing bents must be designed to sustain the forces expected to develop up to buckling of the bracing members. In the second approach, the beams must also resist the gravity loads together with a fraction of the brace loads that are induced after buckling of the braces. This second approach aims at minimizing the degradation in storey shear resistance typically exhibited by chevron bracing subjected to strong ground motions, and it is proposed that such braced frames with reinforced beams be designed for reduced seismic loads. Both design procedures are applied to typical multistorey braced frames to examine their economical impacts. Three different beam strength levels were considered for the second design method. The results show that the saving expected from reducing the seismic loads in the second design approach is generally offset by the increase in beam sizes required by this method. However, the braced frames with stronger beams exhibit a much higher storey shear resistance after buckling of the bracing members has occurred.Key words: earthquakes, seismic, design, steel, structures, braced frames, bracing members, beams, columns, connections.

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