scholarly journals A Pull-down Dynamic Analysis of Two-Span Steel Frames Subjected to Progressive Collapse

2018 ◽  
Author(s):  
Mohammadjavad Esfandiari ◽  
Girum Urgessa
Keyword(s):  
Dynamic Analysis ◽  
Linear Time ◽  
Progressive Collapse ◽  
Steel Frames ◽  
Time History ◽  
Experimental Results ◽  
Efficient Design ◽  
Structural Element ◽  
Disproportionate Collapse ◽  
Non Linear

Progressive collapse, also known as disproportionate collapse, describes a chain reaction of structural element failures in which a primary structural element failure results in the failure of adjoining structural elements. It eventually causes widespread structural damages and a disproportionate collapse. While high level finite-element models incorporating non-linear dynamic analysis will produce more realistic results in progressive collapse scenarios, they are computationally time consuming. Therefore, the development of a non-linear time history pull-down model that is validated with experimental results would be beneficial for producing acceptable and efficient design solutions, particularly for practicing structural engineers. In this paper, a non-linear time history pull-down model of a two-span steel frame is analyzed in ETABS. The ETABS model results are compared with experimental results of two steel frames with two-spans conducted by the National Institute of Standards and Technology (NIST). The NIST experiments include beam-column assemblies from the second-floor framing system of a ten-story building and each span is 20 feet long. The numerical results from ETABS pull-down analysis showed good agreement with the results from the NIST experimental study.

scholarly journals A PULL-DOWN DYNAMIC ANALYSIS OF TWO-SPAN STEEL FRAMES SUBJECTED TO PROGRESSIVE COLLAPSE

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Mohammadjavad Esfandiari ◽  
Girum Urgessa
Keyword(s):  
Dynamic Analysis ◽  
Linear Time ◽  
Progressive Collapse ◽  
Steel Frames ◽  
Time History ◽  
Experimental Results ◽  
Efficient Design ◽  
Structural Element ◽  
Disproportionate Collapse ◽  
Non Linear

Progressive collapse, also known as disproportionate collapse, describes a chain reaction of structural element failures in which a primary structural element failure results in the failure of adjoining structural elements. It eventually causes widespread structural damages and a disproportionate collapse. While high level finite-element models incorporating non-linear dynamic analysis will produce more realistic results in progressive collapse scenarios, they are computationally time consuming. Therefore, the development of a non-linear time history pull-down model that is validated with experimental results would be beneficial for producing acceptable and efficient design solutions, particularly for practicing structural engineers. In this paper, a non-linear time history pull-down model of a two-span steel frame is analyzed in ETABS. The ETABS model results are compared with experimental results of two steel frames with two-spans conducted by the National Institute of Standards and Technology (NIST). The NIST experiments include beam-column assemblies from the second-floor framing system of a ten-story building and each span is 20 feet long. The numerical results from ETABS pull-down analysis showed good agreement with the results from the NIST experimental study.

Evaluation of Dynamic Analysis Methods for Seismic Analysis of Drydocks

2009 ◽  
Vol 43 (1) ◽  
pp. 73-92
Author(s):  
Charles Kubic
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Seismic Analysis ◽  
Linear Time ◽  
Time History ◽  
Army Corps ◽  
Response Model ◽  
Soil Response ◽  
Linear Finite Element ◽  
Non Linear

AbstractThree numerical methods are used to model the structural response of Bremerton drydock no. 6 to the 2001 Nisqually earthquake. The models considered include: (1) a numerical linear-elastic soil response model, (2) a numerical non-linear time-history response model, and (3) a non-linear finite element model. The results of the models are compared to the observed drydock response and each other in order to determine their effectiveness in modeling drydock structures. The research demonstrated that the non-linear finite element program PLAXIS is suitable for the seismic analysis of drydocks. In addition, the research showed that the existing United States Army Corps of Engineers program CorpsWallROTATE is not suited for the dynamic analysis of drydocks; while a method developed by Wood in 1973 could be further developed to be used as a linear approximation of the drydock’s time-history seismic response. The research is presented to assist in the development of comprehensive seismic drydock design standards.

scholarly journals Investigating Non-Linear Dynamic Behavior of Dual Steel Frames under the Effect of Near and Far Fields to Fault

2016 ◽  
Author(s):  
Hamid Reza Ashrafi ◽  
Soroush Dadgar ◽  
Peyman Beiranvand
Keyword(s):  
Linear Time ◽  
Steel Frames ◽  
Time History ◽  
Base Shear ◽  
Construction Planning ◽  
Construction Time ◽  
Linear Dynamic ◽  
Non Linear ◽  
Average Formation ◽  
3D Software

This study sought to investigate steel frames’ performance with dual lateral loader system (Frame bending + bracings of divergent and convergent) in near and far filed to fault. In order to this, four categories of steel frame with dual system with 8, 10 and 12 story are designed with average formation based on existing seismic regulation in 2800 standard of Iran and tenth chapter of national regulations of construction (planning and performing steel construction). Time history non-linear dynamic analysis under the effect of near and far field earthquakes has been done on plan’s models. Then the maximum of floors’ dislocation, floors’ drift, roof dislocation, base shear and energy curves of frames are shown and compared with each other. All non-linear time history analyses have been accomplished using PERFORM 3D software.

scholarly journals Record-to-record variability and code-compatible seismic safety-checking with limited number of records

2021 ◽  
Author(s):  
Fatemeh Jalayer ◽  
Hossein Ebrahimian ◽  
Andrea Miano
Keyword(s):  
Seismic Hazard ◽  
Linear Time ◽  
Time History ◽  
Time History Analysis ◽  
Seismic Safety ◽  
Hazard Curve ◽  
History Analysis ◽  
Non Linear ◽  
Seismic Hazard Curve ◽  
Cloud Analysis

AbstractThe Italian code requires spectrum compatibility with mean spectrum for a suite of accelerograms selected for time-history analysis. Although these requirements define minimum acceptability criteria, it is likely that code-based non-linear dynamic analysis is going to be done based on limited number of records. Performance-based safety-checking provides formal basis for addressing the record-to-record variability and the epistemic uncertainties due to limited number of records and in the estimation of the seismic hazard curve. “Cloud Analysis” is a non-linear time-history analysis procedure that employs the structural response to un-scaled ground motion records and can be directly implemented in performance-based safety-checking. This paper interprets the code-based provisions in a performance-based key and applies further restrictions to spectrum-compatible record selection aiming to implement Cloud Analysis. It is shown that, by multiplying a closed-form coefficient, code-based safety ratio could be transformed into simplified performance-based safety ratio. It is shown that, as a proof of concept, if the partial safety factors in the code are set to unity, this coefficient is going to be on average slightly larger than unity. The paper provides the basis for propagating the epistemic uncertainties due to limited sample size and in the seismic hazard curve to the performance-based safety ratio both in a rigorous and simplified manner. If epistemic uncertainties are considered, the average code-based safety checking could end up being unconservative with respect to performance-based procedures when the number of records is small. However, it is shown that performance-based safety checking is possible with no extra structural analyses.

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