Papers by Keyword: Collapse

Abstract: The aim of this work is to develop a numerical model and perform numerical simulations of avalanche-like collapse of buildings and structures in case of fire and explosions, taking into account the peculiarities of soil performance and its properties. The LIRA-SAPR software is a promising tool for calculations and modelling.

Abstract: This work discusses pattern collapse-free drying by application of a sacrificial polymer during the semiconductor wafer cleaning process. The sacrificial polymer is dispensed onto the wafer, displacing the rinse liquid and subsequently dried to form a solid polymer fill within the patterned structure, providing both mechanical support and a means for dry polymer removal by either plasma or thermal exposure. Polymer film thickness, gap fill capability and removal rate are explored for plasma ashable and thermally removable polymer families.

Abstract: Bridge redundancy is defined as the ability of a bridge system to continue to carry load after the failure of one or several structural components. A bridge will collapse progressively after the failure in some main components, if the bridge is in short of redundancy. The system factors for redundancy have been investigated in the design of the bridges with simple systems. However, there is no corresponding redundancy criteria established for the bridges with long span and complicated structural systems. This paper studied the superstructure of a through steel box tied arch bridge. The member failure state, ultimate limit state and functionality limit state were analyzed with ‘Step-by-Step’ procedure. Thus, the most critical component and weakest damaged systems are determined. It is concluded that this through steel box tied arch bridge has enough level of redundancy. This finding could be a reference for the design and maintenance for bridges with similar structural systems.

Abstract: In recent years the ability to simulate and predict disproportionate collapse has seen growing interest among the scientific community. This is a challenging matter, since many authors have been dealing with the modeling of progressive collapse, and it is now well-established that such problem requires the use of many different non-standard modeling techniques together with extensive calibration. Despite the many papers in the literature, there is still a lack of methodologies tailored for the quantification of the structural robustness and its acceptable level, which clearly depends on the importance and function of the structure. Further, consideration of Performance Criteria as well as Decision Making Strategies, have to be supported by robust (but also efficient) modeling methods that have to include three-dimensional and geometrical non-linear effects. Some of the previously outlined principles about robustness will be discussed following which the authors present a methodology for taking into account that progressive collapse phenomena are governed not only by the dynamic response of the bays adjacent to the triggering event, but also by the residual plastic resources the structure conserves after the initial damage.

Abstract: The formation of a caldera poses a serious risk for the society and the environment. There are several established processes (mostly dealing with the conditions inside the reservoir), which must take place in order to reach a collapse leading to the caldera. The role of magma chamber geometry is investigated in this paper, exploiting the numerical modeling. The results indicates that the knowledge of the magmatic system dimensions can provide a helpful factor for an assessment of the caldera formation scenario.

Abstract: Saturation-unsaturation process of compacted clay fill may lead to loss of shear strength and collapse compression or heave of the fill. These are the two main engineering problems associated with compacted clay fills and naturally before, granular based compacted fills are often employed at construction sites. Use of granular material for compaction may not be economical and sustainable. Therefore, a laboratory-based study was carried out to examine the structure of the compacted clay when used as backfill material. Several kaolin clay specimens prepared under similar condition were subjected to wetting with and without K₀ control.

Abstract: More high-rise structures are currently being constructed and correspondingly, the compressive strength of concrete has been increased. However, compared to conventional strength concrete the high strength concrete (HSC) exhibits coarse inner pore structure which blocks escape routes of vapour generated in the event of fire. This results in spalling and subsequently, are responsible for fire vulnerability of the structure. In addition, spalling phenomena is also affected by the section dimensions of HSC which is also another crucial factor from socio-economic considerations. Thus, this study was carried out to evaluate the fire resistance performance of hybrid fiber (i.e. steel-polypropylene-fibre)-reinforced HSC columns with different cross-section dimensions. The result of the fire resistance performance testing using 100MPa concrete showed that delay to failure was observed by approximately 76 per cent.

Abstract: This paper analyzes the reason of a steel truss building which collapsed under a snow disaster. Firstly, the investigation and inspection in site are introduced. Secondly, based on the on site work, such as the property of the metal materials and the quality of the welding joint, the status of the structure is comprehensively determined. Thirdly, through calculation with the former results, the reason of the collapse accident is obtained. Finally, some related suggestions are proposed for the design and construction of this kind of structure.

Abstract: In light of the special topography in loess gully areas, the mining subsidence disasters in which are classified into three types. The evolution process and formation mechanism of each subsidence type are analyzed, and puts forward corresponding control countermeasures. The collapse disaster is considered to be caused mostly when tensile stress in rock or soil exceed their tensile strength, while the landslide disaster is mainly initiated when shear stress exceed the shear strength. The slumping disaster, however, possess both the tensile failure and the shear failure mechanism. Methods of reducing damages such as coordinated and height-limit mining, designing protective coal pillar, backfill mining and mining down the slope can be adopted to prevent mining subsidence disasters in gully influence scope. Control measures such as slope cutting, crack grouting, collapse backfilling, support and reinforcement, planting vegetation are meanwhile needed. Measures for the restoration and emergency management must be taken after the disaster.

Abstract: Multi-storey RC-frame structure occupies a large proportion of the building structure in our country, the collapse of multi-storey frame structure in great earthquake is very serious, and it has become a major threat to people's life and property security, so research of the rule about structural collapse and define the critical state of structural collapse accurately is necessary. This paper focuses on the rule of structural collapse, takes constant stiffness multi-layer RC-frame structure as the object of study, with height, span and number of floors as the variables, uses nonlinear finite element software ANSYS/LS-DYNA, bases on elastic-plastic time history analysis, studies the rule of plastic deformation’s development of constant stiffness multi-layer RC-frame structure, and the relationship between story-drift and structural collapse.