Tall building collapse mechanisms initiated by fire: Mechanisms and design methodology (original) (raw)
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Local collapse phenomenon is quite well known and may occur under different type of charges, even from pure gravitational or extraordinary actions like blasts (accidental or induced), earthquakes, and collisions with bodies in motion or others. After the total or partial collapse of several important buildings of which the best known are the WTC towers (New York, 2001) and Alfred Murrah (Oklahoma City, 1995) the specialists in civil engineering began to treat more seriously and accuracy the problem of completely avoiding progressive or general collapse or just in the first instance in order to ensure complete evacuation of people and / or important goods. Considering these aspects, in this paper I'll present two parallel study cases for buildings with 5 and 10 levels, which is supposed to have a local collapse of one first floor column (corner, marginal or central) realizing simple or complex analysis in order to identify problems that ascend on the whole building.
Structures Congress 2013, 2013
Fire risks pose significant threats to the integrity and stability of the multi-story steel structures. The robustness of these structures against a fire hazard requires further attention. The progressive collapse of a high-rise structure is detrimental not only to the inhabitants in the building but also to the surrounding infrastructure. The collapse of World Trade Center Twin Towers showed that the impact location and the fire distribution could cause symmetrical as well as asymmetrical types of total collapse. This study investigates the uncoupled structural-thermal response of a 49 story steel high-rise structure. The structural load carrying system of the high-rise structure is assumed to be a moment resisting frame. The results show that the structural response and the progressive collapse differ depending on the fire spread and it does not significantly change due to the fire location as long as the fire is contained on a single floor. This study intends to provide a better understanding of the effect of fire loading leading to the collapse mechanism of a multi-story steel structure.
The impact of fire scenario to the collapse of a tall structure
2013
The aim of this study is to investigate the effect of the fire load to a tall structure and draw conclusions for a more robust structural design. If a building is not properly designed and constructed to with-stand potentially catastrophic events due to risk factors posed by fires, such disasters can nullify the benefits gained from green construction. Leadership in Energy and Environmental Design (LEED) developed by the U.S. Green Building Council and other international certification organizations. One common aspect of most of these certification systems is a lack of consideration for the impact of risks such as fire hazard on sustainability. In order to design sustainable tall structures, their robustness against extreme fire scenarios must be adequately satisfied. In this study, a generic tall structure is modeled using the finite element software LS-Dyna. The two-dimensional model consists of line elements (beams and columns) as well as the shell elements (concrete deck). To simulate the building collapse, the explicit dynamic analysis is used with proper surface-based contact configurations.
Numerical Simulations on the Collapse Behaviors of High-Rise Towers
International Journal of Protective Structures, 2012
In this paper, several numerical simulations of framed structures were performed to identify the specific structural cause of the high-speed total collapse of the World Trade Center (WTC) towers, which occurred during the 9/11 terrorist attacks. A full-scale aircraft impact simulation of the WTC tower 2 was conducted to examine the dynamic unloading phenomena that occurred in the core columns during impact, which may have caused the destruction of the splices between column sections. Fire-induced progressive collapse analyses of a high-rise tower with an outrigger truss system were carried out to qualitatively demonstrate the effects of fire patterns and structural parameters on the behavior of this tower's collapse. In general, the tower remained standing for a longer period of time due to the catenary action of the outrigger truss system only if the load paths in the tower were protected and if the member connections were strong enough. However, in these analyses, the collapse...
A REVIEW ON PROGRESSIVE COLLAPSE OF STRUCTURES AND ITS EFFECT
isara solutions, 2020
A review of progressive collapse and the various factors which cause it has been brought in this paper. Progressive collapse of a building can be referred as the situation where the local failure of a primary load bearing or structural component lead to the collapse of the adjoining member and to an overall damage of the structure. It has been figured out that buildings which were built as per current design codes were not robust enough under the action of accidental load and it failed progressively. Progressive collapse is not proportional to the original local damage. This phenomenon is also called as disproportionate collapse, for the reason that the collapse is out of proportion in comparison to the original triggering event. Progressive collapse occur when one or more vertical load members particularly columns are damaged during extreme events (i.e. terrorist attacks, fire, explosions, vehicle impacts etc.). When a column is failed the gravity load of the building is transferred to the adjoining members of the structure and if the other members of the structure are not properly designed to bear and redistribute the additional loads, then the substantial part of the structure may collapse thus causing greater damage to the structure than the initial impact. It is always accompanied by serious personal and material losses. Since the start of the 21st century there has been growing interests in the risks associated with extreme, especially after the attacks on the Alfred P. Murrah Federal Building in Oklahoma in 1995 and on the World Trade Centre in New York in 2001. Because of these collapses which have led to a huge loss of life and property, the idea has become accepted worldwide that there is a need for robust structures which can bear/sustain local failures with suffering progressive collapse.
1 Assessment of Progressive Collapse in Multi-Storey Buildings
2015
A simplified framework is proposed for progressive collapse assessment of multi-storey buildings, considering sudden column loss as a design scenario. This framework can be applied at various levels of structural idealisation, and enables the quantification of structural robustness taking into account the combined influences of redundancy, ductility and energy absorption. Three main stages are involved in the proposed approach: i) determination of the nonlinear static response, ii) dynamic assessment using a novel simplified approach based on energy conservation, and iii) ductility assessment at the maximum dynamic deformed configuration. The application of the proposed method is illustrated on a multi-storey steel-framed composite building, where the relative importance of various joint details and levels of axial restraint is highlighted. Importantly, the study underlines the inadequacy of prescriptive tying force requirements that neglect ductility issues, and demonstrates that t...
Numerical Simulation of Threat-Independent Progressive Collapse
Civil Engineering Dimension, 2011
A threat-independent approach is usually utilized for progressive collapse analysis of buildings. This approach is referenced in the current guidelines such as "Progressive Collapse Analysis and Design Guidelines for New Federal Office Buildings and Major Modernization Projects" by the U.S. General Service Administration and "Design of Buildings to Resist Progressive Collapse" by the U.S. Department of Defence. However, more studies are required to accurately observe the influence of structural parameters to the response of structures in progressive collapse phenomenon. A parametric study was conducted using advanced nonlinear finite element analysis to assess the utility of the procedures in these documents. The results of the numerical simulations show that a variation of the beam dimensions moderately affects the dynamic load factor. The load factor increases as the beam dimensions increase. Other parameters such as the column dimensions, number of storeys and span lengths, have only negligible effects on the value of the dynamic load factor.
Progressive collapse analysis of steel structures under fire conditions
2012
In this paper a robust static-dynamic procedure has been developed. The development extends the capability of the Vulcan software to model the dynamic and static behaviour of steel buildings during both local and global progressive collapse of the structures under fire conditions.
2008
Throughout recent history, famous records of building failures may be found, unfortunately accompanied by great human loss and major economic consequences. One of the mechanisms of failure is referred to as ‘progressive collapse’: one or several structural members suddenly fail, whatever the cause (accident or attack). The building then collapses progressively, every load redistribution causing the failure of other structural elements, until the complete failure of the building or of a major part of it. The civil engineering community’s attention to this type of event was first drawn by the progressive collapse of the building called Ronan Point, following a gas explosion in one of the last floors. Different simplified procedures for simulating the effects of progressive collapse can now be found in the literature, some of them described in detail. However, no extensive study can be found, in which these procedures are compared to more complete approaches for progressive collapse si...