scholarly journals Assessment of Progressive Collapse Resistance of Steel Structures with Moment Resisting Frames

Buildings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 19 ◽  
Author(s):  
Osama Mohamed ◽  
Rania Khattab
Keyword(s):  
Progressive Collapse ◽  
Three Dimensional ◽  
The United States ◽  
Dimensional System ◽  
Structural System ◽  
Linear Elastic ◽  
Load Carrying ◽  
Non Linear ◽  
Moment Resisting ◽  
Primary Load

This paper evaluates the practice of using moment connections in the perimeter of the structural system and shear connections within the interior connections of the three-dimensional structural system from the perspective of resistance to progressive collapse. The enhanced resistance to progressive collapse associated with using moment resisting connections at the perimeter as well as internal to the three-dimensional system is assessed. Progressive collapse occurrence and system resistance are determined using the alternate path method which presumes a primary load carrying-member is notionally removed. The paper compares the structural response determined using linear elastic, non-linear elastic and non-linear dynamic analyses. Linear and non-linear static analyses are found to be incapable of capturing the response pursuant to the loss of the primary load carrying member. The analysis procedures used in this study followed (for the most part) the United States Department of Defense Guide for Progressive Collapse Resistant Design of Structures.

scholarly journals A New Modular Structural System for Tall Buildings Based on Tetrahedral Configuration

Buildings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 240
Author(s):  
Giulia Angelucci ◽  
Fabrizio Mollaioli ◽  
Roberto Tardocchi
Keyword(s):  
Mechanical Performance ◽  
Three Dimensional ◽  
Analytical Formula ◽  
Tall Buildings ◽  
Optimal Topology ◽  
Dimensional System ◽  
Structural System ◽  
Tetrahedral Configuration ◽  
The Impact ◽  
Modular Structures

Inspired by the high mechanical performance of diagrid structures, the minimization of material consumption on braced tubes and the expressive potency of tensegrity modular structures, this work proposes an innovative three-dimensional system for tall buildings. A new modular structural system generated from the assembly of tetrahedral units is investigated. The paper integrates insights on the architectural implications and mechanical performance of the reticular system arranged in repetitive triangular-based modules. The impact of different geometric configurations of the structural members on the economic design is also discussed and recommendations for the optimal topology are made. Guidelines for the design and analytical formula for accessing preliminary member sizes are proposed on the basis of stiffness requirements.

The FDA's Quality Revolution

2015 ◽  
Vol 21 (4) ◽  
Author(s):  
Peter J. Pitts
Keyword(s):  
Three Dimensional ◽  
The United States ◽  
Adverse Event Reporting ◽  
Dimensional System ◽  
Dimensional Approach ◽  
Event Reporting ◽  
Pharmaceutical Quality ◽  
Two Dimensional System ◽  
Main Strategy

Let it be said that the spark that ignited the flame was when FDA leadership asked, “Do we know enough about the quality of drugs that are sold in the United States.”In 2009, the FDA announced its Safe Use of Drugs Initiative.  The theory being that one way to make drugs safer is to ensure that they are used as directed. The main strategy was education and the agency’s efforts were (and are) aimed at physicians, nurses, pharmacists, and patients.Earlier this year, the agency announced not just an office, but a Super Office of Pharmaceutical Quality, further underscoring that the FDA operates not under a two-dimensional system of safety and efficacy, but a three-dimensional approach that includes quality … with a capital (indeed a “super”) Q.Since there is no such thing as a safe substandard product, the agency is putting time, resources, and the use of the bully pulpit to go beyond cGMPs, API and excipient sourcing to develop a risk-based approach that includes data gathered from a variety of sources including manufacturing inspections, adverse event reporting, and substandard pharmaceutical events as evidenced in the agency’s bioequivalence- driven actions with bupropion in 2012, metoprolol in 2014, and methylphenidate in 2015.So, in many respects, pharmaceutical quality is both a pre and post-licensure endeavor and, like Safe Use, a scientific and educational enterprise that requires close coordination with many stakeholders. And it won’t come easily or inexpensively. As Aristotle said that, “Quality is not an act, it is a habit.”

Three-dimensional deformations in a single-lap joint

1994 ◽  
Vol 29 (2) ◽  
pp. 137-145 ◽  
Author(s):  
M Y Tsai ◽  
J Morton
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Stress Distributions ◽  
Lap Joint ◽  
Displacement Fields ◽  
Element Analysis ◽  
Linear Elastic ◽  
Non Linear ◽  
Linear Effects ◽  
Peel Stress

The three-dimensional nature of the state of deformation in a single-lap test specimen is investigated in a linear elastic finite element analysis in which the boundary conditions account for the geometrically non-linear effects. The validity of the model is demonstrated by comparing the resulting displacement fields with those obtained from a moiré inteferometry experiment. The three-dimensional adherend and adhesive stress distributions are calculated and compared with those from a two-dimensional non-linear numerical analysis, Goland and Reissner's solution, and experimental measurements. The nature of the three-dimensional mechanics is described and discussed in detail. It is shown that three-dimensional regions exists in the specimen, where the adherend and adhesive stress distributions in the overlap near (and especially on) the free surface are quite different from those occurring in the interior. It is also shown that the adhesive peel stress is extremely sensitive to this three-dimensional effect, but the adhesive shear is not. It is also observed that the maximum value of the peel stress occurs at the end of the overlap in the central two-dimensional core region, rather than at the corners where the three-dimensional effects are found. The extent of three-dimensional regions is also quantified.

Failure From Creep as Influenced by the State of Stress

1943 ◽  
Vol 10 (4) ◽  
pp. A202-A212
Author(s):  
W. Siegfried
Keyword(s):  
United States ◽  
Experimental Data ◽  
Grain Boundaries ◽  
Three Dimensional ◽  
The United States ◽  
Dimensional System ◽  
State Of Stress ◽  
Brittle Fractures ◽  
Combined Action ◽  
Three Dimensional System

Abstract As early as 1912, it was pointed out by Rosenhain and Ewen (1) that the behavior of metals at high temperatures could be explained by the combined action of the crystals and the so-called grain boundaries. This theory was also made use of later to explain problems in connection with creep phenomena (2). The author discusses subsequent studies in the United States and Germany, relating to the occurrence of brittle fractures in metals after long periods of time. With the aid of the Rosenhain-Ewen conceptions, he attempts to reconcile discrepancies between recent observations on the occurrence of inter-crystalline fractures after long test periods. His evaluation of the theories cited offers an explanation of various phenomena which previously could not be interpreted, and also furnishes a basis for determining the risk of failure with creep in a three-dimensional system of stress. He concludes that the problem of calculating the strength of a material subjected to creep is actually solved only when the metallurgist and the steel manufacturer are in a position to furnish the designer with complete experimental data enabling him to predict failure for all systems of stress occurring in practice.

scholarly journals A sensitivity interpolation algorithm for the concurrent optimization of bodies sharing a common design space

2021 ◽  
Author(s):  
Giorgio Previati ◽  
Massimiliano Gobbi ◽  
Federico Ballo
Keyword(s):  
Design Problem ◽  
Design Space ◽  
Three Dimensional ◽  
Simultaneous Optimization ◽  
Topological Optimization ◽  
Dimensional System ◽  
Concurrent Optimization ◽  
Load Carrying ◽  
Three Dimensional System ◽  
Two Bodies

AbstractIn this paper the problem of the concurrent topological optimization of two different bodies sharing a region of the design space is dealt with. This design problem focuses on the simultaneous optimization of two bodies (components) where not only the material distribution of each body has to be optimized but also the design space has to be divided among the two bodies. This novel optimization formulation represents a design problem in which more than one component have to be located inside a limited allowable room. Each component has its own function and load carrying requirements. In the paper a novel development solution algorithm is presented. With respect to previously published papers, the new algorithm comprises an interpolation of the density fields which allows a complete independence of the meshes of the two bodies. As the bodies can be meshed with any arbitrary mesh, this new algorithm can be applied to any real geometry. The developed algorithm is used to design a complex three dimensional system, namely a multi-component arm for a tube bending machine.

Three-Dimensional Steady Flow in Non-Linear Elastic Collapsible Tubes

2009 ◽  
Author(s):  
Wonhyuk Koh ◽  
Sungwoo Kang ◽  
Myunghwan Cho ◽  
Jung Yul Yoo
Keyword(s):  
Steady Flow ◽  
Elastic Material ◽  
Three Dimensional ◽  
Elastic Tube ◽  
Wall Material ◽  
Linear Elastic Material ◽  
Linear Elastic ◽  
Collapsible Tubes ◽  
Elastic Wall ◽  
Non Linear

Three-dimensional fluid-structure interaction problem arising from steady flow in non-linear elastic tube is studied numerically by using a finite element software, ADINA. Strain-energy density function is used for non-linear elastic analysis of solid material. Navier-Stokes equation coupled with elastic wall condition is solved for the fluid flow. To simulate interactions between the fluid and the solid domains, arbitrary Lagrangian-Eulerian (ALE) formulation is utilized. For validation, thin-walled linear elastic collapsible tubes is computed and compared with previous numerical results. The tube collapses into the buckling mode N = 2 and the results are in excellent agreement with a previous study. Then, the results for linear elastic tube are compared with those for non-linear elastic tube to show the effects of non-linear elasticity of the wall. The wall material is considered to be non-linear hyperelastic and isotropic. The non-linear elastic wall shows the tendency to preserve its shape more than the linear material. The deformation patterns, pressure distributions of the tube with non-linear elastic material are significantly different from those with linear elastic material.

Mitigation of Progressive Collapse by the Activation of the Elasto-Plastic Catenary Behaviour of R.C. Slab Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Fabrizio Palmisano
Keyword(s):  
Critical Load ◽  
Design Process ◽  
Progressive Collapse ◽  
Extreme Conditions ◽  
Structural System ◽  
Technical Standards ◽  
Extreme Loads ◽  
The United Kingdom ◽  
Load Carrying ◽  
The Cost

Mitigation of progressive collapse was highlighted in 1968 with the collapse of the Ronan Point building in the United Kingdom. Technical standards followed suit with increased requirements and recommendations to encourage the design and construction of more robust buildings. The intent has been to establish a design process that recognizes and considers the potential that buildings could experience abnormal and extreme loads or events that seriously compromise one or more critical load-carrying elements. This article aims to show that if the main goal of the design is to protect human lives in these extreme conditions, even sacrificing the building functionality, simple measures such as the activation of the elasto-plastic catenary behaviour of the slab reinforcement, could be very effective to increase the building robustness without substantially increasing the cost of a structural system.

Linear analysis of a three-dimensional multistorey steel-frame structure under varying temperatures

2019 ◽  
Vol 10 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Parthasarathi N. ◽  
Satyanarayanan K.S. ◽  
Thamilarau V. ◽  
Prakash M.
Keyword(s):  
Progressive Collapse ◽  
Three Dimensional ◽  
Linear Analysis ◽  
Steel Frame ◽  
Frame Structure ◽  
Effect Of Temperature ◽  
Content Type ◽  
Moment Resisting ◽  
Collapse Behavior ◽  
Steel Frame Structure

PurposeThe purpose of this study is progressive collapse behavior in buildings. It occurs due to removal/damage of a column by fire, blast or vehicle impact.Design/methodology/approachThe present study investigates the comparative behavior of 3D four-storey moment resisting steel frame using ABAQUS to predict the sensitivity of the structure in progressive collapse because of fire loads. Columns at different levels were given different temperature with reduced material properties and yield strength. Progressive collapse load combination was adopted as per General Service Administration guidelines. Corner, middle, intermediate, multiple corner and multiple intermediate columns were subjected to fire load separately.FindingsThe results for displacement, stress, shear force and axial force were captured and discussed.Originality/valueThe study covers linear analysis of steel frame because of different temperature. In linear analysis. columns were subjected to different temperature and their results were studied. Effect of temperature in the structure were captured because of different fire conditions.

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.

A New Approach to Compute the Non-Linear Whipping Response Using Hydro-Elastoplastic Coupling

2020 ◽  
Author(s):  
George Jagite ◽  
Hervé le Sourne ◽  
Patrice Cartraud ◽  
Šime Malenica ◽  
Fabien Bigot ◽  
...  
Keyword(s):  
Structural Model ◽  
Three Dimensional ◽  
Structural Behavior ◽  
New Approach ◽  
Hull Girder ◽  
Structural Part ◽  
Linear Elastic ◽  
Non Linear ◽  
Dimensional Boundary ◽  
Collapse Behavior

Abstract In the last ten years, the importance of whipping on the extreme hull girder loads has received much attention, but its consequence on the hull girder’s collapse is still unclear. The most common practice is to consider the structural behavior as linear-elastic in the hydro-elastic coupling, and as non-linear elasto-plastic in the ultimate strength evaluation. In order to investigate the influence of the non-linear structural behavior on the hydro-structure interaction responses, a new hydro-elastoplastic model is proposed to compute the non-linear whipping response. The structural part is modeled as two beams connected by a non-linear hinge, which follows the collapse behavior of a ship’s hull girder. The hydrodynamic problem is solved using the three-dimensional boundary element method, and the exact coupling between the structural model and the hydrodynamic one is made by making use of the shape function approach. Finally, the fully-coupled hydro-elastoplastic problem is solved directly in time-domain by numerical integration.

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