scholarly journals Improving the Structural Reliability of Steel Frames Using Posttensioned Connections

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Edén Bojórquez ◽  
Arturo López-Barraza ◽  
Alfredo Reyes-Salazar ◽  
Sonia E. Ruiz ◽  
Jorge Ruiz-García ◽  
...  
Keyword(s):  
Ground Motion ◽  
Structural Reliability ◽  
Narrow Band ◽  
Steel Frames ◽  
Steel Structures ◽  
Incremental Dynamic Analysis ◽  
Spectral Acceleration ◽  
Residual Drift ◽  
Interstory Drift ◽  
Moment Resisting

In this paper, various moment-resisting steel frames (MRSFs) are subjected to 30 narrow-band motions scaled at different ground motion intensity levels in terms of spectral acceleration at first mode of vibration SaT1 in order to perform incremental dynamic analysis for peak and residual interstory drift demands. The results are used to compute the structural reliability of the steel frames by means of hazard curves for peak and residual drifts. It is observed that the structures exceed the threshold residual drift of 0.5%, which is perceptible to human occupants, and it could lead to human discomfort according to recent investigations. For this reason, posttensioned connections (PTCs) are incorporated into the steel frames in order to improve the structural reliability. The results suggest that the annual rate of exceedance of peak and residual interstory drift demands are reduced with the use of PTC. Thus, the structural reliability of the steel frames with PTC is superior to that of the MRSFs. In particular, the residual drift demands tend to be smaller when PTCs are incorporated in the steel structures.

Evaluation of Structural Reliability of Steel Frames: Interstory Drift versus Plastic Hysteretic Energy

2011 ◽  
Vol 27 (3) ◽  
pp. 661-682 ◽  
Author(s):  
Edén Bojórquez ◽  
Amador Terán-Gilmore ◽  
Sonia E. Ruiz ◽  
Alfredo Reyes-Salazar
Keyword(s):  
Structural Reliability ◽  
Steel Frames ◽  
General Idea ◽  
Structural Performance ◽  
Hysteretic Energy ◽  
Response Parameter ◽  
Interstory Drift ◽  
Lake Zone ◽  
Moment Resisting ◽  
Different Response

The structural reliability in terms of maximum interstory drift—and, alternatively, in terms of plastic hysteretic energy—is evaluated for six regular moment-resisting steel frames designed according to the Mexico City Building Code, and located in the Lake Zone of that city. While the maximum interstory drift was used because of its relevance within the format of current seismic design codes, the plastic hysteretic energy was considered due to its importance for the performance of structures when subjected to severe cumulative plastic deformation demands. The demand hazard curves of the frames in terms of drift and energy are compared to provide a general idea of the reliability levels associated to the models, and to provide insights into which response parameter dominates their dynamic behavior and structural performance. In some cases, large differences are observed in the reliabilities computed by measure of the two different response parameters under consideration.

scholarly journals CORRELATION BETWEEN INTENSITY MEASURE PARAMETERS OF GROUND MOTION EARTHQUAKES AND STRUCTURAL RESPONSE OF MOMENT RESISTING STEEL FRAMES

2020 ◽  
Vol 32 (3) ◽  
Author(s):  
Emad Ali Elhout
Keyword(s):  
Ground Motion ◽  
Pearson Correlation ◽  
Steel Frames ◽  
Structural Response ◽  
Time History ◽  
Base Shear ◽  
Intensity Measure ◽  
Response Parameter ◽  
Drift Ratio ◽  
Moment Resisting

Identify and select a suitable ground motion intensity measure (IMs) parameters associated with the structural response to specific levels of damages or collapse in structures are very important in the seismic response of structural analyses. This paper investigated the correlation between 25 intensity measure (IMs) parameters of earthquakes and the structural response parameters of 3-, 6- and 12-story moment resisting steel frames (MRSFs). Nonlinear time history analyses are performed for these frames under near- and far-source ground motion records. The maximum story drift ratio (MSDR), the roof drift ratio (RDR), and the maximum base shear force (SF) are chosen as the structural response parameters. The Pearson correlation coefficient with the regression analyses is utilized to display the correlation between the structural response parameter and the ground motion IMs parameters. The results reveal that MSDR appears to be a suitable engineering demand parameter to correlate with most of the ground motion IMs parameters compared to both the RDR and the SF parameters. Also, Max. Incremental velocity (MIV) parameter is considered as the highest correlated IMs parameters with MSDR in both near- and far-source earthquakes.

scholarly journals Performance of steel structures during the 1994 Northridge earthquake

1995 ◽  
Vol 22 (2) ◽  
pp. 338-360 ◽  
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.

scholarly journals On California Structural Steel Seismic Design

1986 ◽  
Vol 2 (4) ◽  
pp. 703-727 ◽  
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.

scholarly journals On California structural steel seismic design

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.

scholarly journals EC3-Compatible Methods for Analysis and Design of Steel Framed Structures

Modelling ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 567-590
Author(s):  
Sofia Antonodimitraki ◽  
Pavlos Thanopoulos ◽  
Ioannis Vayas
Keyword(s):  
Cross Section ◽  
Steel Frames ◽  
Steel Structures ◽  
Ultimate Capacity ◽  
Framed Structures ◽  
Analysis And Design ◽  
Order Analysis ◽  
Advantages And Disadvantages ◽  
Moment Resisting ◽  
Safe Side

The behaviour of steel structures is affected by two nonlinearities—the geometric and material nonlinearity—and by the unavoidable presence of imperfections. To evaluate the ultimate capacity of a structure, these effects should be taken into consideration during the design process, either explicitly in the analysis or implicitly through the verification checks. In this context, Eurocode 3 provides several design approaches of different complexity and accuracy. The advantages and disadvantages of these approaches are discussed. Five different methods in conformity with the Eurocode provisions are applied for the design of four moment resisting steel frames of varying slenderness. The influence of nonlinearities and imperfections in respect to the slenderness of the structure is illustrated. The examined methods are compared in terms of the predicted ultimate capacity and their efficiency is assessed against the most accurate between them, i.e., an advanced geometrically and materially nonlinear analysis. It is shown that considerable differences arise between the methods. Nevertheless, except for the commonly used 2nd order analysis followed by cross-section verifications, the remaining methods are mostly on the safe side.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

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