Linear Static Analysis For Progressive Collapse Of Steel Structure Under Fire Loads (original) (raw)
Related papers
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.
Progressive collapse analysis of two existing steel buildings using a linear static procedure
Structural Engineering and Mechanics, 2013
There are numerous threats which could cause progressive collapse in a structure that may lead to fatality. After the incident in Oklahoma Murrah building and the recent terrorist attacks, such as WTC (World Trade Center) in 2001, it became more important to do assessment towards preventing the progressive collapse. Although, there have been many researches carried out on progressive collapse, the increase in terrorist attacks, especially loss of lives (nearly 3000 died in the attacks of September 2001) in the World Trade Center case, lead to the development of new guidelines, such as General Services Administration (GSA), Department of Defense (DoD), and Unified Facilities Criteria (UFC) for assessing and preventing progressive x
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.
Determination of fire induced collapse mechanisms of multi-storey steel framed structures
… European Conference on …, 2005
Following the events of September 11th 2001, understanding the performance of multistorey buildings during large-scale fires has assumed greater importance. These events have highlighted the possibility of large uncontrolled fires lasting for several hours (WTC-7). Owners of high-rise buildings are seeking assurance that integrity can be maintained during similar elevated temperature situations. This work is part of a much larger study to evaluate the performance of high-rise steel-framed structures in the event of large uncontrolled fires, using primarily a computational approach. Given a building and its operating conditions, different fire scenarios are established. The choice of scenarios is established on the basis of probability of occurrence and also as a function of damage potential. Computational fluid dynamics models are used to predict critical conditions within predetermined areas of the building. Emphasis is given to establish a proper thermal boundary condition for the structural elements. A three dimensional numerical model of the structure provides the basis for a structural finite element analysis to be carried out under combined static and thermal loading. Full investigation of the temperatures and stresses generated on structural members due to the design fire chosen are considered. Particular attention to detail is given to those members that are thought likely to contribute to total collapse through localised failure. This is done by combining CFD codes with finite element models. This paper will present a selection of results from the aforementioned investigation, with particular emphasis on the conditions that cause total collapse for the chosen case study.
STUDY OF PROGRESSIVE COLLAPSE IN G+8 MULTI-STOREY BUILDING
Progressive Collapse denotes a global structural system breakdown disproportionally triggered by local structural deterioration. An uncommon occurrence involving local element removal criteria due to natural forces or artificial risks. When one or more vertical load-bearing elements are removed due to artificial (Explosions, Vehicular Collisions) or natural dangers (Earthquake, Tsunami), the progressive collapse of reinforced concrete structures is triggered. The weight of the building is transferred to adjacent columns in the structure, failing adjacent components and failing a portion of the entire structure system. In which the collapsing system constantly seeks other load pathways to survive. When one or more vertical load-bearing elements are removed due to artificial or natural dangers, the progressive collapse of reinforced concrete structures is triggered. The building's weight is transferred to adjacent columns and beams in the structure, failing adjacent components and failing a portion of the entire structure system. In which the collapsing system constantly seeks other load pathways to survive. Performing Linear static analysis in the G+8 storey R.C.C. building using ETABS Software Version 16.0. According to G.S.A. regulations, the demand capacity ratio is evaluated in the critical zone of the R.C. part connected with the eliminated column.
Progressive Collapse Mechanisms of Steel Frames Exposed to Fire
Advances in Structural Engineering, 2014
OpenSees is an open-source object-oriented software framework developed at UC Berekeley. The OpenSees framework has been recently extended to deal with structural behavior under fire conditions. This paper summaries the key work done for this extension and focuses on the application of the developed OpenSees to study the fire-induced progressive collapse mechanisms of steel structures. The implicit dynamic analysis method (Newmark method) is applied and the influences of the load ratios, beam sizes and fire scenarios on the collapse behavior of frames are investigated. Single-compartment fire scenarios in the central bay and edge bay are considered, respectively. A total of four collapse mechanisms of steel frames are proposed by varying the three influencing factors. Most of the collapse of steel frames is triggered by the buckling of the heated columns. The thermal expansion of heated beams at early heating stage and their catenary action at high temperature have great influences ...
- Progressive Collapse is a local failure of a primary structural component leads to collapse of adjoining member which leads to additional collapse. Hence the total damage is disproportionate to the original cause. The most common local failure is framed structural is to be column failure. This paper compares the influences of several modelling approach for progressive collapse assessment of steel frame structure, considering sudden column loss as design scenario. A linear static analysis based on the GSA-2013 guidelines is used as preliminary study to determine progressive collapse analysis of low rise steel frame structure with and without bracing system. In this study, a column at the different position and different story level is removed to simulate an effect of an extreme event and the remaining structure is analysed using a finite element software ETABS 2015. The structure is analysed for gravity load and seismic load. Then the structure is checked for the Demand Capacity Ratio as per GSA 2013.
The collapse behaviour of braced steel frames exposed to fire
2011
Progressive collapse mechanisms of braced two-dimensional steel-framed structures, subjected to fire heating, are investigated using a robust static-dynamic procedure developed by the authors. 20 cases have been analysed to provide a comprehensive view of the mechanisms of progressive collapse for these frames, with different bracing systems under different fire conditions. The influences of stiffness and strength of the bracing systems are also analysed. The results indicate that the pull-in of columns is one of the main factors which generate progressive collapse. Horizontal "hat truss" bracing systems have limited capacity to avoid pull-in of columns supporting the heated floor, although they can directly redistribute the vertical load lost by buckling columns to adjacent columns. On the other hand, vertical bracing systems have the effect, not only of increasing the lateral restraint of the frame, which reduces the pull-in of the columns, but also of effectively preventing the collapse progressing from local to global. Stronger vertical bracing systems can redistribute load from a buckled column to its surrounding structural members. Frames with a combined hat and vertical bracing system can be designed to enhance the capability of the frame as much as possible to prevent progressive collapse when a heated column buckles.
Effect of Initial Local Failure Type on Steel Braced Frame Buildings against Progressive Collapse
International Journal of Engineering
In many studies, the alternative load path method (APM) has been used for progressive collapse analysis. In this method, one or several columns of the building are removed and the building response is investigated. This method ignores the initial local failure cause of building and this can affect the structural response. Investigation of ignoring the initial local failure cause of steel braced frames is the main purpose of this research. The variables include the type of progressive collapse investigation (ignoring the initial cause of failure or APM, considering blast loading and the heat caused by the fire as the initial causes of failure) and the location of the initial local failure in plan (outer and inner frame) and in floors (1st, 2nd and 3rd). 4-story braced steel buildings were simulated using ABAQUS software and the responses were compared using different methods. The most important results showed that the axial forces are very noticeable in the columns around the damaged site if the initial local failure caused by explosive loading; while these forces are ignored when APM is used. Therefore, due to this significant difference, if the design of a steel building is to be considered against progressive collapse, it is recommended to consider the initial local failure in order to make the appropriate design in accordance with it. Therefore, the initial loading type has a very significant effect on the structure response, and ignoring the initial local failure can lead to incorrect predictions of the structure response.
Civil Engineering and Architecture, Horizon Research and Publishing Corporation, USA, 2024
The purpose of progressive collapse analysis is to examine that by eliminating different columns whether a structure remains stable following the guidelines of General Services Administration of US. For this analysis, we have considered a G+10 storied RC frame building consisting of 4X4 bay of 84 ft. in X-axis (Long direction) and 52 ft. in Y-axis (Short direction) designed by the Bangladesh National Building Code (BNBC) 2020. For structural analysis, a numerical model is developed by using finite element-based software and progressive collapse analysis is performed according to GSA guidelines. We are considering three types of column sections (rectangular, circular, rectangular column with shear wall) and these three types of columns have similar cross-sectional area. For each type of building, we have considered removing three columns (corner column, exterior column & interior column). For buildings with shear wall along with rectangular column, the DCR values are well within the safe merging recommended by GSA guideline among all the considered three cases. On the other hand, the beams of the buildings with rectangular and circular column sections are not safe for progressive collapse although the columns of these buildings are safe.