scholarly journals Progressive collapse scenario in steel structures with irregularity in height

2021 ◽  
Vol 73 (09) ◽  
pp. 893-905
Keyword(s):  
Cross Sections ◽  
Progressive Collapse ◽  
Great Influence ◽  
Nonlinear Dynamic Analysis ◽  
Structural Response ◽  
Steel Structures ◽  
Nonlinear Static Analysis ◽  
Load Path ◽  
Engineering Structures ◽  
Column Removal

Sudden removal of load-bearing elements such as columns in engineering structures, and lack of sufficient capacity to withstand the overload caused by removal of these elements can cause damage and Progressive Collapse (PC) in structures. Therefore, the effect of sudden column removal and structural capacity against PC scenarios in medium and high-rise buildings is investigated in this study. The irregularity in height has a great influence on lateral behaviour of structures and it affects the design of cross-sections. Various sudden column removal scenarios are investigated in this research for steel structures with and without irregularity in height. To assess the effects of sudden column removal, the Alternate load Path Method (APM) and Nonlinear Dynamic Analysis (NDA) are utilized. In addition, a Nonlinear Static Analysis (NSA) is performed to investigate the capacity of structures against the PC phenomenon. Using OpenSees software, 10-, 15- and 20-storey structures with three distinct irregularity types are analysed during four different column removal scenarios. The results are presented in the form of static and dynamic nonlinear curves. The results indicate that making geometric irregularity in height in the sudden column removal scenario can cause the reduction of capacity and growth of the structural response in comparison to the structure with regularity in height. Moreover, the capacity of structures increases and the dynamic response declines by increasing the number of elements in the structures.

Improvement of progressive collapse resistance potential of semi-rigid jointed steel frames through bracings

2016 ◽  
Vol 7 (4) ◽  
pp. 518-546
Author(s):  
Milan Bandyopadhyay ◽  
Atul Krishna Banik
Keyword(s):  
Static Analysis ◽  
Progressive Collapse ◽  
Steel Frames ◽  
Nonlinear Dynamic Analysis ◽  
Nonlinear Static Analysis ◽  
Braced Frame ◽  
Collapse Resistance ◽  
Column Removal ◽  
Rigid Frames ◽  
Nonlinear Static

Progressive collapse studies of both unbraced and braced semi-rigid jointed steel frames have been carried out to evaluate the contribution of bracings in improving progressive collapse resistance potential. Numerical models of 10-story frames with different types of semi-rigid connections have been developed using SAP2000. Progressive collapse potential of semi-rigid frames is first investigated without bracings. Bracings are then included in a systematic manner, and response of the braced frame is compared with that of unbraced frame to evaluate the contribution of bracings. Two different arrangements of bracings, that is, bay-wise and floor-wise arrangements, are considered to find out a preferred arrangement of bracings. Parametric studies include eight column removal conditions at center and corner locations of different floors. Development of catenary action has also been considered as it gives additional resistance, especially to braced frame. Apart from nonlinear static analysis, effects of bracings are evaluated also through nonlinear dynamic analysis and the responses of the frames in nonlinear dynamic analysis are compared with those of nonlinear static analysis. From the study, it is found that provision of bracings significantly improves the progressive collapse resistance potential of the semi-rigid frames under different column removal conditions. Floor-wise arrangement of bracings is much effective as compared to bay-wise arrangement.

Structural reliability of RC frames under sudden column removal scenarios considering static and dynamic methods

2021 ◽  
Author(s):  
Luchuan Ding ◽  
Ruben Van Coile ◽  
Wouter Botte ◽  
Robby Caspeele
Keyword(s):  
Dynamic Analysis ◽  
Structural Reliability ◽  
Progressive Collapse ◽  
Nonlinear Dynamic Analysis ◽  
Load Path ◽  
Dynamic Amplification Factor ◽  
Mean Values ◽  
Column Removal ◽  
Column Removal Scenario ◽  
Failure Probabilities

<p>The alternative load path (ALP) method is widely used to investigate the performance of reinforced concrete (RC) buildings in case of progressive collapse (or disproportional collapse) scenarios. This kind of analysis can be carried out either in a static way or in a dynamic way. In this contribution, these methods are compared by means of nonlinear static and nonlinear dynamic analysis methods. A 5-storey RC frame subjected to two different sudden column removal scenarios is adopted as a case study. The probabilistic analysis considers 12 random variables. On the basis of the stochastic results, a dynamic amplification factor (DAF) is calculated. The mean values of the DAF are 1.114 and 1.102 for the external column removal scenario (Case A) and the internal column removal scenario (Case B), respectively. Compared to the failure probabilities obtained through a static analysis, the failure probabilities for the incremental dynamic analysis results are 184.0% and 180.7% higher for Case A and Case B, respectively.</p>

scholarly journals Progressive Collapse Assessment: A review of the current energy-based Alternate Load Path (ALP) method

2019 ◽  
Vol 258 ◽  
pp. 02012 ◽  
Author(s):  
Nur Ezzaryn Asnawi Subki ◽  
Hazrina Mansor ◽  
Yazmin Sahol Hamid ◽  
Gerard Parke
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Progressive Collapse ◽  
Structural Response ◽  
Steel Frame ◽  
Collapse Mechanism ◽  
Load Path ◽  
Acceptance Criterion ◽  
Current Energy ◽  
Collapse Assessment

The Alternate Load Path (ALP) is a useful method that has generated a considerable recent research interest for the assessment of progressive collapse. The outcome of the ALP analysis can be assessed either using the force-based approach or the energy-based approach. The Unified Facilities Criteria (UFC- 4- 023-03) of progressive collapse guideline - have outlined that the force-based approach can either be analysed using static or dynamic analysis. The force-based approach using static analysis is preferable as it does not require a high level of skill and experience to operate the software plus no effort is required in scrutinising the validity of the analysis results output. However, utilising the static approach will eliminate the inertial effect in capturing the actual dynamic response of the collapsed structure. In recent years, the development of the energy-based progressive collapse assessment is attracting widespread interest from researchers in the field; as the approach can produce a similar structural response with the force-based dynamic analysis by only using static analysis. Most of the current energy-based progressive collapse assessments are developed following the requirements which are given in the progressive collapse guidelines provided by the Unified Facilities Criteria. However, little attention is given to the development of the energy-based approach using the Eurocode standards as a base guideline. This article highlights the merits of utilising the energy-based approach against the force-based approach for a collapsed structure and explains the collapse mechanism of a steel frame in the perspective of the energy concept. The state of the art of energy-based progressive collapse assessment for a structural steel frame is reviewed. The comprehensive review will include insights on the development of the energy-based method, assumptions, limitations, acceptance criterion and its applicability with the European standards. Finally, potential research gaps are discussed herein.

Investigation on Damage-Involved Structural Response of Colliding Steel Structures during Ground Motions

2016 ◽  
Vol 713 ◽  
pp. 26-29 ◽  
Author(s):  
Barbara Sołtysik ◽  
Tomasz Falborski ◽  
Robert Jankowski
Keyword(s):  
Dynamic Properties ◽  
Ground Motions ◽  
Structural Response ◽  
Steel Structures ◽  
Separation Distance ◽  
Shaking Table ◽  
Engineering Structures ◽  
Positive Role ◽  
Acceleration Time Histories ◽  
Adjacent Structures

Earthquakes are the most unpredictable damaging loads which can affect civil engineering structures. Due to insufficient separation distance between adjacent structures with different dynamic properties, structural collisions may occur during ground motions. Although the research on structural pounding has recently been much advanced, the studies have mainly been conducted for concrete structures. The aim of this paper is to show the results of experimental investigation, focused on dynamic behaviour of closely-separated three models of steel structures which have been subjected to damaging earthquake excitations. The study was performed using three models of steel towers with different dynamic parameters and various distances between the structures. The acceleration time histories of the Kobe and the Northridge earthquakes were applied as the seismic excitation. The unidirectional shaking table, located at the Gdansk University of Technology (Poland), was used in the experimental study. The results have confirmed that collisions may lead to the increase in the structural response, although they may also play a positive role, depending on the size of the separation gap between the structures.

scholarly journals Progressive Collapse Analysis of Latticed Telecommunication Towers under Wind Loads

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Shan Gao ◽  
Sheliang Wang
Keyword(s):  
Wind Direction ◽  
Progressive Collapse ◽  
Nonlinear Dynamic Analysis ◽  
High Standard ◽  
Wind Loads ◽  
Sensitivity Index ◽  
Load Path ◽  
Collapse Analysis ◽  
Telecommunication Towers ◽  
Progressive Collapse Analysis

As the antenna-supporting structures, latticed telecommunication steel towers are considered as critical members of telecommunication infrastructures. It is necessary to perform progressive collapse analysis of lattice telecommunication towers under wind loads. The present study conducts a nonlinear dynamic analysis on 50 m high typical standard latticed telecommunication tripole tower and angle tower by alternative load path method. The finite element models for two towers subjected to design wind loads are developed by ABAQUS. The analysis results show that, for 50 m high standard tripole tower, the member failure in the first three tower sections from tower top would not trigger the collapse of the tower. From the fourth tower section to tower bottom, the member failure at certain wind direction may cause a collapse. For 50 m high standard angle tower, the single member failure in any tower section would not cause the collapse of the tower. A dynamic sensitivity index is proposed to identify the most unfavorable wind direction for tripole tower and angle tower. A progressive collapse fragile curve based on collapse probability of telecommunication tower under wind loads is proposed to assess the anticollapse performance of the towers.

Evaluation of Progressive Collapse of Special Steel Moment Frames

2013 ◽  
Vol 831 ◽  
pp. 85-89
Author(s):  
A. Valadbeigi ◽  
M. Ghassemieh
Keyword(s):  
Progressive Collapse ◽  
Nonlinear Dynamic Analysis ◽  
Structural Response ◽  
Vertical Displacement ◽  
Cover Plate ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Special Steel

The point of this study was to assess the progressive collapse resisting capacity of special steel moment frame structures and the behaviour of buildings which have different height when they are losing one of their exterior columns. Two buildings were considered for this research, 7-storiy and 12-storiy buildings. Corner column as well as one of the middle columns was removed to evaluate the importance and the effect of the location of removed column in structural response. General Services Administration (GSA) and Department of Defence (DoD) guidelines are considered for choosing the method of analysis. Nonlinear dynamic analysis procedures were carried out to investigate the behavior of structures. Thus, maximum vertical displacement in the point of column removal for each structure was measured. In addition, both buildings have cover plate connections which are cosidered to be rigid in modelling.

Simplified Procedure for Progressive Collapse Analysis of Steel Structures

2011 ◽  
Vol 255-260 ◽  
pp. 482-486
Author(s):  
Arash Naji ◽  
Fereidoon Irani
Keyword(s):  
Nonlinear Dynamic ◽  
Progressive Collapse ◽  
Nonlinear Dynamic Analysis ◽  
Steel Structures ◽  
Displacement Curve ◽  
Structural Element ◽  
Accurate Analysis ◽  
Collapse Analysis ◽  
Simplified Procedure ◽  
Progressive Collapse Analysis

Progressive collapse refers to a phenomenon in which a local damage of a primary structural element leads to the failure of partial or whole structural system. To investigate the progressive collapse of structures, nonlinear dynamic procedure leads to more accurate results than static procedures. Nonlinear dynamic procedure is very complicated and the evaluation or validation of its results may be very time-consuming. Therefore using simplified methods are very important. This paper presents a simplified and accurate analysis procedure for progressive collapse analysis of steel structures. The proposed method results show to have good agreement with nonlinear dynamic analysis results. Also, the capacity curve obtained from dividing the accumulated area under the nonlinear static load-displacement curve by the corresponding displacement of the column-removed point is used to predict the progressive collapse resistance of the column-removed structure.

scholarly journals Performance Assessment of an Energy–Based Approximation Method for the Dynamic Capacity of RC Frames Subjected to Sudden Column Removal Scenarios

2021 ◽  
Vol 11 (16) ◽  
pp. 7492
Author(s):  
Luchuan Ding ◽  
Ruben Van Coile ◽  
Wouter Botte ◽  
Robby Caspeele
Keyword(s):  
Model Uncertainty ◽  
Probabilistic Models ◽  
Progressive Collapse ◽  
Deformation Mode ◽  
Dynamic Resistance ◽  
Load Path ◽  
Capacity Curve ◽  
Column Removal ◽  
Damping Effects ◽  
Column Removal Scenario

The alternative load path method is widely used to assess the progressive collapse performance of reinforced concrete structures. As an alternative to an accurate non–linear dynamic analysis, an energy–based method (EBM) can also be adopted to approximately calculate the dynamic load–bearing capacity curve or the dynamic resistance based on a static capacity curve. However, dynamic effects cannot be explicitly taken into account in the EBM. The model uncertainty associated with the use of the EBM for evaluating the dynamic ultimate capacity of structural frames has not yet been quantified. Knowledge of this model uncertainty is however necessary when applying EBM as part of reliability calculations, for example, in relation to structural robustness quantification. Hence, this article focuses on the evaluation of the performance of the EBM and the quantification of its model uncertainty in the context of reliability–based assessments of progressive or disproportionate collapse. The influences of damping effects and different column removal scenarios are investigated. As a result, it is found that damping effects have a limited influence on the performance of the EBM. In the case of an external column removal scenario, the performance of the EBM is lower as the response is not a single deformation mode according to the results in the frequency domain. However, a good performance is found in the case of an internal column removal scenario in which the assumption of a single deformation mode is found to be sufficiently adequate. Probabilistic models for the model uncertainties related to the use of the EBM compared to direct dynamic analyses are proposed in relation to both the resistances and the associated displacements. Overall, the EBM shows to be an adequate approximation, resulting in a small bias and small standard deviation for its associated model uncertainty.

scholarly journals Assessment on the Progressive Collapse Resistance of a Long-Span Curved Spatial Grid Structure With Main Trusses

2021 ◽  
Author(s):  
Guangpan Zhou ◽  
Qianen Song ◽  
Aiqun Li ◽  
Shungao Shen ◽  
Qing Zhou ◽  
...  
Keyword(s):  
Progressive Collapse ◽  
Nonlinear Dynamic Analysis ◽  
Grid Structure ◽  
Load Path ◽  
Cross Sectional ◽  
Safety Control ◽  
Initial Failure ◽  
Long Span ◽  
Collapse Resistance ◽  
Spatial Grid

Abstract The present work is aimed at studying the progressive collapse resistance of the terminal building of Zhongchuan Airport in Lanzhou, China, which is a long-span curved spatial grid structure with main trusses. Firstly, the finite element model was built using MSC.Marc software. The alternate load path method (AP method) was used to simulate the initial failure of component. An improved method of zoned concept judgment and sensitivity analysis was proposed to determine the key components. Then, the initial failure components were removed individually on the course of analyzing. The responses of remaining structure were calculated using nonlinear dynamic analysis method. According to the results, the structure has a strong ability of resisting progressive collapse, though the structural responses are significant when removing the concrete filled steel tubular column directly supporting the roof at cantilever end. The maximum vertical displacement reaches 10 m. Moreover, the proposed method can avoid omitting the key components having significant influence on structural progressive collapse resistance. In addition, the influences brought by the cross-sectional sizes of chord and web members were investigated through conducting parametric analysis. The research can provide references for the structural optimization and safety control of similar long-span spatial structures.

Analytical Investigation of Progressive Collapse Resistance Mechanism in Steel Moment Frame with Fiber Model

2012 ◽  
Vol 166-169 ◽  
pp. 1848-1853 ◽  
Author(s):  
Chuan Qing Liu ◽  
Zuo Yun Mei
Keyword(s):  
Progressive Collapse ◽  
Resistance Mechanism ◽  
Element Model ◽  
Steel Frame ◽  
Frame Structure ◽  
Load Path ◽  
Bending Resistance ◽  
Column Removal ◽  
Steel Frame Structure ◽  
Middle Column

In order to investigate the resistance mechanism of steel frame structure in progressive collapse, an advanced finite element model(FEM) is presented based on fiber beam-column element. Using this FEM, non-linear static pushdown analysis of a ten-story structure was carried out by the alternate load path method, in the two cases that two different columns are removed respectively. Analytical results show that residual structure has the different resistance mechanism for the different column removal case. In the initial stage, bending resistance mechanism can provide dominate resistance capacity in the structural progressive collapse, after both middle and side columns are removed. However, when the bending resistance is out of work, the catenary action is induced in the case of the middle column removal only, which is not developed after the side column is removed. It can be seen that steel frame structure has higher collapse risk in the case of the side column removal than in the case of the middle column removal.

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