scholarly journals A Review on Progressive Collapse of Building Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 183-192 ◽  
Author(s):  
Hao Wang ◽  
Anqi Zhang ◽  
Yi Li ◽  
Weiming Yan
Keyword(s):  
Design Method ◽  
Progressive Collapse ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Collapse Mechanism ◽  
Building Structures ◽  
Wide Range ◽  
Collapse Behavior ◽  
Element Method

Progressive collapse of building structures is generally triggered by a local failure due to accidental actions, followed by subsequent chain effect of the structures which may result in wide range failure or even collapse of the entire buildings. Since the “911” event, progressive collapse of building structures has been widely concerned by engineers and researchers. This paper assesses the current researches on this issue from experimental study, numerical simulation and theoretical analysis. Given the limitation of costs and difficulties of experimental tests, the experimental studies investigate the collapse mechanism, such as development of stress/strain and damage/failure of materials, mainly via the scaled down specimens of structural components and substructures. On the other hand, the collapse behavior of entire building structures is analyzed via the numerical methods, such as the finite element method and the discrete element method. Further, the collapse resistance demand and the robustness assessment for building structures are theoretically studied in depth in which the simplified theoretical models of the collapse-resisting demand and the collapse risk assessment are proposed respectively. At last, the design method to prevent progressive collapse for building structures is also discussed.

scholarly journals Experimental and Numerical Evaluation of Progressive Collapse Behavior in Scaled RC Beam-Column Subassemblage

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Rasool Ahmadi ◽  
Omid Rashidian ◽  
Reza Abbasnia ◽  
Foad Mohajeri Nav ◽  
Nima Usefi
Keyword(s):  
Numerical Model ◽  
Progressive Collapse ◽  
Experimental Tests ◽  
Resistance Mechanisms ◽  
Full Scale ◽  
Displacement Curve ◽  
Rc Beam ◽  
Rc Structures ◽  
Collapse Behavior ◽  
Column Removal Scenario

An experimental test was carried out on a 3/10 scale subassemblage in order to investigate the progressive collapse behavior of reinforced concrete (RC) structures. Investigation of alternative load paths and resistance mechanisms in scaled subassemblage and differences between the results of full-scale and scaled specimens are the main goals of this research. Main characteristics of specimen response including load-displacement curve, mechanism of formation and development of cracks, and failure mode of the scaled specimen had good agreement with the full-scale specimen. In order to provide a reliable numerical model for progressive collapse analysis of RC beam-column subassemblages, a macromodel was also developed. First, numerical model was validated with experimental tests in the literature. Then, experimental results in this study were compared with validated numerical results. It is shown that the proposed macromodel can provide a precise estimation of collapse behavior of RC subassemblages under the middle column removal scenario. In addition, for further evaluation, using the validated numerical model, parametric study of new subassemblages with different details, geometric and boundary conditions, was also done.

A Review of Theoretical and Experimental Research on Various Autofrettage Processes

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Rajkumar Shufen ◽  
Uday S. Dixit
Keyword(s):  
Experimental Studies ◽  
Theoretical Models ◽  
Pressure Vessels ◽  
Future Research ◽  
Spherical Vessel ◽  
Considerable Research ◽  
Wide Range ◽  
Set Up ◽  
Compressive Residual Stresses ◽  
Spherical Pressure

Autofrettage is a metal forming technique widely incorporated for strengthening the thick-walled cylindrical and spherical pressure vessels. The technique is based on the principle of initially subjecting the cylindrical or spherical vessel to partial plastic deformation and then unloading it; as a result of which compressive residual stresses are set up. On the basis of the type of the forming load, autofrettage can be classified into hydraulic, swage, explosive, thermal, and rotational. Considerable research studies have been carried out on autofrettage with a variety of theoretical models and experimental methods. This paper presents an extensive review of various types of autofrettage processes. A wide range of theoretical models and experimental studies are described. Optimization of an autofrettage process is also discussed. Based on the review, some challenging issues and key areas for future research are identified.

RESEARCH OF THE STABILITY ANALYSIS FOR FRAME BUILDINGS USING FINITE ELEMENT METHOD

2019 ◽  
Vol 7 (1) ◽  
pp. 45-48
Author(s):  
Галина Кравченко ◽  
Galina Kravchenko ◽  
Елена Труфанова ◽  
Elena Trufanova ◽  
Анастасия Бойко ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Design Method ◽  
Progressive Collapse ◽  
Structural Member ◽  
Mode Shapes ◽  
Frame Buildings ◽  
The Stability ◽  
Element Method

In this article, general stability analysis is considered, in order to obtain the load-bearing capacity of the multy-storey building using finite element method. There are some graphical interpretations for FE results that illustrate safety factor for each structural member of the structure and different mode shapes with their corresponding frequencies. These results can be used to improve the structural member design method in case of progressive collapse possibility. The article provides recommendations for strengthening and design of structural member.

scholarly journals Epidermal devices for noninvasive, precise, and continuous mapping of macrovascular and microvascular blood flow

2015 ◽  
Vol 1 (9) ◽  
pp. e1500701 ◽  
Author(s):  
R. Chad Webb ◽  
Yinji Ma ◽  
Siddharth Krishnan ◽  
Yuhang Li ◽  
Stephen Yoon ◽  
...  
Keyword(s):  
Blood Flow ◽  
Continuous Monitoring ◽  
Human Subjects ◽  
Experimental Studies ◽  
Continuous Mapping ◽  
Theoretical Models ◽  
Motion Artifacts ◽  
Microvascular Blood Flow ◽  
Sensor Technology ◽  
Wide Range

Continuous monitoring of variations in blood flow is vital in assessing the status of microvascular and macrovascular beds for a wide range of clinical and research scenarios. Although a variety of techniques exist, most require complete immobilization of the subject, thereby limiting their utility to hospital or clinical settings. Those that can be rendered in wearable formats suffer from limited accuracy, motion artifacts, and other shortcomings that follow from an inability to achieve intimate, noninvasive mechanical linkage of sensors with the surface of the skin. We introduce an ultrathin, soft, skin-conforming sensor technology that offers advanced capabilities in continuous and precise blood flow mapping. Systematic work establishes a set of experimental procedures and theoretical models for quantitative measurements and guidelines in design and operation. Experimental studies on human subjects, including validation with measurements performed using state-of-the-art clinical techniques, demonstrate sensitive and accurate assessment of both macrovascular and microvascular flow under a range of physiological conditions. Refined operational modes eliminate long-term drifts and reduce power consumption, thereby providing steps toward the use of this technology for continuous monitoring during daily activities.

Multi-facets of kinetic roughening of interfaces

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Palash Nath ◽  
Debnarayan Jana
Keyword(s):  
Morphological Evolution ◽  
Experimental Studies ◽  
Film Surface ◽  
Theoretical Models ◽  
Interface Roughness ◽  
Physical Parameters ◽  
Scaling Exponents ◽  
Kinetic Roughening ◽  
Thin Film Surface ◽  
Wide Range

Abstract In this review, the authors are going to explore the intriguing aspects of kinetic roughening of interfaces. Interface roughness dynamics connected with various physical processes have been studied through novel microscopic models in connection with experiments. The statistical properties of such rough interfaces appearing in wide range of physical systems are observed to belong to different universality classes characterized by the scaling exponents. With the advancement of characterization techniques, the scaling exponents of thin-film surface (or the morphological evolution of amorphous surfaces eroded by ion bombardment) are easily computed even in situ during the growing (erosion) conditions. The relevant key physical parameters during the dynamics crucially control the overall scaling behaviour as well as the scaling exponents. The non-universal nature of scaling exponents is emphasized on the variations of the physical parameters in experimental studies and also in theoretical models. Overall, this review containing both theoretical and experimental results will unfold some novel features of surface morphology and its evolution and shed important directions to build an appropriate theoretical framework to explain the observations in systematic and consistent experiments.

Research on Numerical Model for Earthquake Induced Progressive Collapse of High-Rise Buildings

2014 ◽  
Vol 716-717 ◽  
pp. 223-226
Author(s):  
Yi Xuan Wang ◽  
Lei Huang
Keyword(s):  
Structural Damage ◽  
Progressive Collapse ◽  
Cell Contact ◽  
Collapse Mechanism ◽  
The Finite Element Method ◽  
Contact Algorithm ◽  
High Rise ◽  
Whole Process ◽  
Collapse Behavior ◽  
Weak Zones

Progressive collapse is defined as the collapse of the whole building due to local weak stories or weak zones. In this paper, collapse should theoretically be avoided for any building under any earthquake, it is necessary to study the collapse behavior of buildings to acquire a better understanding of the collapse mechanism and to find efficient methods to prevent it. The collapse process highly depends on the feature of the whole structural system, so numerical simulation becomes a major method to study it. Based on the finite element method, by selecting the appropriate cell death and cell contact algorithm criterion can better simulate the structure collapsed in an earthquake under the continuity of the whole process of destruction, to help understand the causes and mechanism of structural damage. The real buildings are analyzed to study the failure mechanism of the structure. The models proposed are reasonable to study the seismic collapse mechanism of high-rise buildings.

scholarly journals EXPERIMENTAL STUDY OF SHORT STEEL CONCRETE COLUMNS ON STATIC INFLUENCES

2021 ◽  
pp. 25-34
Author(s):  
Mohammad Tahran Hammoud ◽  
Ruslan Pcholkin
Keyword(s):  
Experimental Studies ◽  
Latin Square ◽  
Protective Layer ◽  
Experimental Tests ◽  
Hydraulic Press ◽  
Building Structures ◽  
Standard Samples ◽  
Butt Welding ◽  
The Moment ◽  
Non Destructive

The paper considers the issues of planning an experimental tests of samples of short reinforced concrete supports for static effects. The procedure for determining the required number of samples and their preparation for testing is given. To determine the needed amount of supports the Latin square is used. The variable parameters for such type of construction are the followed: concrete class, the thickness of the expanded-exhaust sheet, the size of the cell of the average exhaust sheet, geometric parameters of the support (diameter and height), diameter and pitch of frame and the degree of adhesion of concrete to metal. Experimental samples are presented in three series: round concrete supports(6 pcs.), concrete supports in a mesh holder (6 pcs.) and concrete supports in a mesh holder supported by outer frames (6 pcs.). The height of each support is about 1000mm, the diameter is 450 mm. Based on the presented methodology, 18 prototypes were prepared for testing, which were made on the construction site of "Avantazh" ICC. For convenience of production of supports concreting is executed in a disposable cardboard framework. The diameter of the mesh holder is 400 mm, thus, the protective layer of concrete is 25 mm. The connection of the holder is made by butt welding without overlays. The frames are made of Ø12A400C reinforcement bars of periodic profile. Before conducting a series of experimental studies, standard tests of structural materials were performed, in particular, determination of the cubic strength of concrete. Simultaneously with the testing of standard samples of cubes, the establishment of the actual concrete classes of the test samples was performed using a non destructive test with the ONYX-2.5 device. Together with determining the concrete classes, geometrical characteristics of samples were defined. A P-500 hydraulic press for testing of building structures is used as the main power plant. The loading of the samples is planned to be realized stepwise through two headers in the form of steel disks till the moment of distruction.

scholarly journals Progressive Collapse Test of Ship Structures in Waves

2018 ◽  
Vol 25 (s3) ◽  
pp. 91-98
Author(s):  
Zhiyong Pei ◽  
Tao Xu ◽  
Weiguo Wu
Keyword(s):  
External Load ◽  
Progressive Collapse ◽  
Time History ◽  
Collapse Mechanism ◽  
Ship Structure ◽  
Hull Girder ◽  
Structural Capacity ◽  
Collapse Behavior ◽  
External Forces ◽  
External Loads

Abstract The external loads and structural ultimate strength are two important aspects for the safety of ship hull girder. It may collapse in case the structural capacity is less than the external forces in extreme seas. In the present research, progressive collapse test is performed to investigate the collapse mechanism of ship structure in waves. External load with time history and corresponding structural collapse behavior are measured and discussed to demonstrate the interaction of fluid and structures.

scholarly journals Modeling damaged precast structural system when its robustness check

2021 ◽  
pp. 63-81
Author(s):  
Viktar TUR ◽  
Andrei TUR ◽  
Aliaksandr LIZAHUB
Keyword(s):  
Progressive Collapse ◽  
Precast Concrete ◽  
Experimental Studies ◽  
Resistance Mechanisms ◽  
Calculation Model ◽  
Dynamic Resistance ◽  
Building Structures ◽  
Structural System ◽  
Non Linear ◽  
Central Column

Within the framework of traditional approaches to checking for resistance of reinforced concrete buildings and structures to the progressive collapse development, membrane (chain) forces in a damaged structural system are calculated separately, without considering its non-linear bending behavior during the formation of the plastic hinges and without checking the possibility of achieving large deflections.The authors propose an approach to modelling a nonlinear quasi-static reaction of a damaged structural system in an accidental design situation. This approach considers non-linear bending and the resistance of reserved horizontal ties, considering their ultimate ductility. The authors verified the proposed approach based on the results of experimental studies by others researchers.An example of the application of the proposed approach in assessing the robustness of a structural system made of precast concrete with a sudden removal of the central column is considered. In accordance with the provisions of the energy approach, an analysis is made of the contribution of individual resistance mechanisms to the total quasi-static and dynamic resistance of the damaged structural system.We show that the proposed calculation model adequately describes the behavior of a damaged structural system in an accidental design situation, and therefore to carry out parametric studies and check the robustness of building structures.

scholarly journals DEVELOPMENT OF FIRE-PROTECTIVE PLASTER SURFACES COMPOSITES AND DESIGN METHOD FOR DETERMINING THE FIRE RESISTANCE OF TWO-LAYER ARMOCEMENT ELEMENTS

2019 ◽  
Author(s):  
Т.А. Хежев
Keyword(s):  
Fire Resistance ◽  
Design Method ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Building Structures ◽  
Resource Base ◽  
Heat Engineering ◽  
Flame Retardant Properties ◽  
Increased Strength ◽  
Acceptable Agreement

Приведены результаты исследований составов гипсоизвестковоцементовермикулитотуфобетонных композитов. Расширение сырьевой базы, повышение прочности и огнезащитных свойств, а также снижение стоимости композита решается за счет использования в сырьевой смеси отходов пиления вулканического туфа. Приведены результаты экспериментальных исследований огнестойкости двухслойных армоцементных элементов. Разработан алгоритм теплотехнического расчета предела огнестойкости многослойных строительных конструкций, обеспечивающий приемлемое совпадение расчетных значений с экспериментальными данными. Разработано программное обеспечение теплотехнического расчета предела огнестойкости армоцементных конструкций с огнезащитным слоем из гипсовермикулитобетона, получены выражения для коэффициентов теплопроводности и теплоемкости разработанных композитов. The results of studies of gypsumlimestone cementvermiculite and concrete composites are given. Expanded resource base, increased strength and flame retardant properties, as well as reduced cost of the composite. using volcanic tuff in the raw mix. The results of experimental studies of the fire resistance of twolayer cementcontaining elements are given. An algorithm for heat engineering calculation of the fire resistance limit of multilayer building structures has been developed, which ensures acceptable agreement between the calculated values and experimental data. The software for the heat engineering calculation of the fire resistance limit of cementcement constructions with a fireproof layer made of gypsum vermiculite concrete has been developed, expressions for the thermal conductivity and heat capacity of the developed composites have been obtained.

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