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Progressive collapse of framed structures: Suggestions for robustness assessment
Full text linkThe term \progressive collapse" has been used to describe the spread of local
failure in a manner analogous to a chain reaction that leads to partial or total collapse of a
structure. Robustness is de ned as a fundamental property of structural systems to prevent
damage propagation and to mitigate the potential of progressive collapse. In this paper, the
progressive collapse capacity of steel moment-resisting frames was rst investigated using
the alternative load path method, then suggestions are made for assessment of structural
robustness, and the robustness of frames is quanti ed. According to the results, the
robustness and progressive collapse potential of the frames varied signi cantly, depending
on the location of the initial local failure and number of building stories
Numerical Analysis of Steel I-Core Sandwich Panels Subjected to Multiple Consecutive Blast Scenarios
No full textThe nonlinear dynamic response of steel I-core sandwich panels under three multiple consecutive blast scenarios using five
different explosive charges has been numerically investigated. The obtained results are compared with available experimental data to verify the developed finite element model, and good agreement is observed. Special emphasis is placed on
the evaluation of maximum displacements of cover plates and energy dissipation of different parts of the panels. According
to the results, sandwich panels show better performance than equivalent solid plate with the same mass and material when
subjected to consecutive blasts. Overall responses of panels are dependent on not only blast pressure, but also the sequence
of loading. In this regard, three different phases of deformation based on blast pressure and sequence are observed in the
response of panels when subjected to multiple blasts
Influence of sudden column loss on dynamic response of steel moment frames under blast loading
Full text linkModeling buildings response to blast and subsequent progressive collapse interested more and more
researchers during the past two decades. Due to the threat from extreme loading, efforts have been
made to develop methods of structural analysis and design. In this paper, progressive collapse capacity
of steel moment frames was first investigated using alternate load path method, then a nonlinear
dynamic analysis was carried out to examine the response of the steel moment frames in blast and
sudden column loss scenario. The structural response of the building under sudden loss of column for
different scenarios of column removal, with or without external blast loading was assessed in detail.
According to the results, progressive collapse potential are strongly dependent on location of column
loss. Loss of column can affect overall response of structure under external blast loads. The obtained
results provide better insight into the influence of sudden column loss on dynamic response of steel
moment frames under blast loading
Numerical study of progressive collapse in framed structures: A new approach for dynamic column removal
Full text linkProgressive collapse is a situation where local failure of a primary structural component leads to the
collapse of adjoining members which, in turn, leads to additional collapse. Hence, the total damage is
disproportionate to the original cause. The most common local failure in framed structure is assumed to
be column failure. In this paper, a new approach for dynamic column removal in framed structures was
proposed. Using this approach, the structural response of a 5-story steel frame building under the
sudden loss of columns for different scenarios of column removal was numerically assessed. Both
material and geometric nonlinearities were taken into account in the analysis. The modeling techniques
were described in details. Special emphasis was focused on the evolution of vertical displacements of
column removal point. According to the results progressive collapse potential are strongly dependent
on location of column loss. It could be concluded that the proposed approach offers the advantages of
computational simplicity and practicality for dynamic column removal of framed structures
Steel plates subjected to uniform blast loading
No full textIn this study, for behavior of steel plate which subjected to uniform blast loading the
general purpose finite element software ABAQUS, was used. The aim of this paper is to recognize
the effect of stiffener configurations, boundary conditions, mesh dependency, load patterns,
geometry of plates and damping on dynamic response of the plates. Special emphasis is focused on
the evolution of mid-point displacements. The results show that stiffener configuration and
boundary conditions have a significant influence on the response, while the effects of damping and
load pattern on maximum response are negligible. The results obtained allow an insight into the
effect of stiffener configurations and other parameters on the response of the plates under uniform
blast loadin
Numerical dynamic analysis of stiffened plates under blast loading
Full text linkUsing the general purpose finite element package Abaqus, an
investigation has been carried out to examine the dynamic response of steel stiffened plates subjected to uniform blast loading.
The main objective of this study is to determine the dynamic
response of the stiffened plates considering the effect of stiffener
configurations. Several parameters, such as boundary conditions,
mesh dependency and strain rate, have been considered in this
study. Special emphasis is focused on the evaluation of midpoint
displacements and energy of models. The modeling techniques
were described in details. The numerical results provide better
insight into the effect of stiffener configurations on the nonlinear
dynamic response of the stiffened plates subjected to uniform blast
loading
Non-linear Dynamic Analysis of Steel Hollow I-core Sandwich Panel under Air Blast Loading
Full text linkIn this paper, the non-linear dynamic response of novel steel sandwich panel with hollow I-core subjected to blast loading was studied. Special emphasis is placed on the evaluation of midpoint displacements and energy dissipation of the models. Several parameters such as boundary conditions, strain rate, mesh dependency and asymmetrical loading are considered in this study. The material and geometric non-linearities are also considered in the numerical simulation. The results obtained are compared with available experimental data to verify the developed FE model. Modeling techniques are described in detail. According to the results, sandwich panels with hollow I-core allowed more plastic deformation and energy dissipation and less midpoint displacement than conventional I-core sandwich panels and also equivalent solid plate with the same weight and material
Effects of finite element modeling and analysis techniques on response of steel moment-resisting frame in dynamic column removal scenarios
No full textDue to the high cost of the experimental progressive collapse tests, numerical simulation has been widely used by
researchers. Finite element method is applied in the majority of numerical progressive collapse studies. In this paper, the
influences of finite element modeling and analysis techniques including solution procedure, mesh size, element type,
column removal time (CRT), damping, strain rate and output-related issues on nonlinear dynamic column removal
response of a steel framed structure are evaluated in detail. According to the results, mesh size and column removal time
have major influence on the structural response in column removal scenarios, while influences of solution procedure and
damping ratio on the maximum response are negligible. Considering the strain-rate effects results in lower response and the
rate of decline mainly depends on column removal time. Results also show that special emphasis should be laid on the
accuracy of saving outputs, because a long interval causes significant change in the estimated response and may lead to
misleading conclusions
Catenary mechanism in steel columns under extreme lateral loading: A basis for building progressive collapse analysis
Full text linkThe studies on progressive collapse have primarily focused on threat-independent methods, wherein a sudden column removal is suggested in codes. However, a real collapse scenario is necessarily threat-dependent. Focusing on blast- and impact-induced progressive collapses, the current study considers cases in which damage is concentrated in a single member, without resulting in complete column loss. It is demonstrated that the progressive collapse performance under specific threats can be better or worse compared to that of sudden column removal. Thus, dynamic column removal does not necessarily guarantee the most critical scenario, as the response in a damaged system can sometimes exceed expectations. A simple analytical model is proposed to describe in detail the observed phenomena and emphasizes the development of catenary forces in the columm under lateral extreme loading scenarios. The results provide a deeper insight into the progressive collapse performance of frame systems and the involved member-level resisting mechanisms
Response of reinforced concrete beams subjected to debris impact: A simplified model
Full text linkRecent research on progressive collapse has predominantly focused on redistributional mechanisms, where load paths are reestablished following the failure of critical members. However, many notable structural failures are governed by impact-type progressive collapse mechanisms, which remain less understood. To address this gap, this study develops a novel analytical model designed to study the dynamic interactions between impacting bodies and reinforced concrete (RC) beams. The model utilizes a mass-spring-damper system and introduces a dynamically recalculated equivalent mass. This advancement enables highly accurate predictions of contact forces, showing up improvements in accuracy compared to existing methods. A comprehensive parametric analysis was conducted, investigating the effects of critical variables such as the impactor's mass, velocity, and beam length. Among these, the velocity of the impactor was identified as the dominant factor that influences structural response, with significant implications for energy dissipation and failure progression. The results underscore the complex interplay between dynamic effects and structural properties, offering valuable insights into failure mechanisms under real-world impact conditions
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