Considering Catenary Action in Designing End-Restrained Steel Beams in Fire

2005 ◽  
Vol 8 (3) ◽  
pp. 309-324 ◽  
Author(s):  
H. X. Yu ◽  
J. Y. Richard Liew
Keyword(s):  
Design Method ◽  
Load Capacity ◽  
Limit State ◽  
Beam Deflection ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Catenary Action ◽  
In Fire

When a building compartment is subjected to fire attack, there are complex interactions between the fire affected members with the surrounding members. The behaviour of the steel frame members in fire can be drastically different from that of its member in isolation. This paper studies the behaviour of steel beams with the increase of temperature from beam action phase to catenary action phase and until failure. The load bearing mechanism in the catenary action phase is discussed and the failure criterion is defined. A new ultimate limit state based on 15% maximum strain of steel material at elevated temperature is proposed to determine the ultimate load capacity of beams failed in the catenary action phase. Wide ranges of beam parameters including various beam sizes and span lengths with different degrees of end restraints are studied. Comparison of results with those obtained from nonlinear finite element analysis shows that the proposed design method could enhance the critical temperature of steel beams by over 200 °C if proper attention is given to the integrity of connections to resist the catenary force. In this respect, methods to estimate the catenary force and beam deflection are provided.

scholarly journals Graphical tool for assessing the critical temperatures of steel beams and columns in fire

Fire Research ◽  
2018 ◽  
Author(s):  
Valdir Pignatta Silva ◽  
Arthur Ribeiro Melão ◽  
Igor Pierin
Keyword(s):  
Critical Temperature ◽  
Design Method ◽  
Limit State ◽  
Local Buckling ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Structural Element ◽  
Critical Temperatures ◽  
Graphical Tool ◽  
In Fire

In a fire situation, the temperature in which the ultimate limit state of the structural element is reached is called critical temperature. It is very laborious to determine it. The aim of this work was to create a graphical tool to allow quick determination of the critical temperature of I shaped columns and beams without local buckling. The method used was based on the Brazilian standard and using AcoInc software developed by the authors. The result was a tool whose similarity was not found in the literature. The use of the tool developed in this study simplifies the use of the standardized design method. One conclusion to be highlighted is one in which constants values of the critical temperature, generally accepted in practice, may be unsafe.

Bearing Capacity of a Skirted Foundation Under VMH Loading

2003 ◽  
Author(s):  
Susan Gourvenec ◽  
Mark Randolph
Keyword(s):  
Finite Element ◽  
Design Method ◽  
Load Capacity ◽  
Limit State ◽  
Design Guidelines ◽  
Shallow Foundation ◽  
Combined Loading ◽  
Ultimate Limit State ◽  
Finite Element Analyses ◽  
Offshore Industry

This paper presents results from a series of three-dimensional finite element analyses investigating the ultimate limit state of a circular skirted shallow foundation over a comprehensive range of combined vertical, moment and horizontal loading. Failure loci in V:M:H load space derived from the finite element analyses are compared with limit state predictions from the offshore industry design guidelines [1]. The comparison highlights considerable conservatism of the current design method largely due to poor representation of the response to fully combined loading and neglect of the tensile capacity achieved with foundation skirts. These shortcomings are particularly significant with respect to foundations for offshore conditions and result in an oversight of considerable potential load capacity in design.

scholarly journals Determination of the ULS, for columns with small dimensions, under biaxial bending and symmetrical fire conditions

2017 ◽  
Vol 10 (2) ◽  
pp. 451-476
Author(s):  
M. CHEREM ◽  
V. PIGNATTA SILVA
Keyword(s):  
Ambient Temperature ◽  
Cross Sections ◽  
Load Capacity ◽  
Limit State ◽  
Ultimate Limit State ◽  
Biaxial Bending ◽  
Structural Engineers ◽  
In Fire ◽  
Ultimate Limit

Abstract Obtaining internal load capacity, in reinforced concrete sections, at ambient temperature, under biaxial bending, is one of the most common tasks done by structural engineers, but not so common when the member is in fire situation. The intention of this paper is to show that is possible to correlate the ultimate limit state (ULS), in fire situation, with ULS at ambient temperature, for square cross sections under fire from all faces. To reach the purpose and give support to the numerical analysis of this article, a computer program, in Delphi language, called COL FIRE, is being developed by the authors.

scholarly journals Mechanical Collapse Testing on Aluminum Stiffened Plate Structures for Marine Applications

2008 ◽  
Vol 45 (04) ◽  
pp. 228-240
Author(s):  
Jeom Kee Paik ◽  
Celine Andrieu ◽  
H. Paul Cojeen
Keyword(s):  
High Speed ◽  
Design Method ◽  
Limit State ◽  
Ultimate Limit State ◽  
Stiffened Plate ◽  
Design Standards ◽  
Element Analysis ◽  
Plate Structures ◽  
Initial Imperfections ◽  
Marine Applications

The present paper is a summary of the R&D results obtained through SSC SR-1446 project sponsored by Ship Structure Committee together with Alcan Marine, France, and Lloyd's Register Educational Trust, UK. It is recognized that the use of ultimate limit state (ULS) design method in addition to more conventional structural design standards will help make possible to move high-speed vessels to open-ocean transiting of large high-speed vessels, which is what the US Navy is certainly trying to do. The aim of the project is to investigate the collapse characteristics of aluminum stiffened plate structures used for marine applications by mechanical testing, together with nonlinear finite element analysis (FEA). Fabrication-related initial imperfections significantly affect the ULS behavior, and thus it is of vital importance to identify the features of initial imperfections prior to ULS computations. In the present study, a statistical database of fabrication-related initial imperfections on welded aluminum stiffened plate structures is also developed. The database and insights developed will be useful for design and building of welded aluminum high-speed oceangoing vessel structures.

Combined flexure and torsion of I-shaped steel beams

1989 ◽  
Vol 16 (2) ◽  
pp. 124-139 ◽  
Author(s):  
Robert G. Driver ◽  
D. J. Laurie Kennedy
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Phase Behaviour ◽  
Inelastic Interaction ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Second Phase ◽  
Design Standards ◽  
Limit States ◽  
Interaction Diagram

Design standards provide little information for the design of I-shaped steel beams not loaded through the shear centre and therefore subjected to combined flexure and torsion. In particular, methods for determining the ultimate capacity, as is required in limit states design standards, are not presented. The literature on elastic analysis is extensive, but only limited experimental and analytical work has been conducted in the inelastic region. No comprehensive design procedures, applicable to limit states design standards, have been developed.From four tests conducted on cantilever beams, with varying moment–torque ratios, it is established that the torsional behaviour has two distinct phases, with the second dominated by second-order geometric effects. This second phase is nonutilizable because the added torsional restraint developed is path dependent and, if deflections had been restricted, would not have been significant. Based on the first-phase behaviour, a normal and shearing stress distribution on the cross section is proposed. From this, a moment–torque ultimate strength interaction diagram is developed, applicable to a number of different end and loading conditions. This ultimate limit state interaction diagram and serviceability limit states, based on first yield and on distortion limitations, provide a comprehensive design approach for these members. Key words: beams, bending moment, flexure, inelastic, interaction diagram, I-shaped, limit states, serviceability, steel, torsion, torque, ultimate.

Risk Analysis for the Construction Phases of Long-Span CFST Arch Bridge Based on Finite Element Analysis

2011 ◽  
Vol 225-226 ◽  
pp. 823-826
Author(s):  
Yu Feng Zhang ◽  
Guo Fu Sun
Keyword(s):  
Finite Element ◽  
Risk Analysis ◽  
Limit State ◽  
Ultimate Limit State ◽  
Element Analysis ◽  
Nonlinear Buckling ◽  
Finite Element Program ◽  
Arch Bridge ◽  
Cfst Arch Bridge ◽  
Element Program

As a part of virtual simulation of construction processes, this paper deals with the quantitative risk analysis for the construction phases of the CFST arch bridge. The main objectives of the study are to evaluate the risks by considering an ultimate limit state for the fracture of cable wires and to evaluate the risks for a limit state for the erection control during construction stages. Many researches have been evaluated the safety of constructed bridges, the uncertainties of construction phases have been ignored. This paper adopts the 3D finite element program ANSYS to establish the space model of CFST Arch Bridge, and to calculate the linear, the geometrical nonlinear and the double nonlinear buckling safety factors under the six different lode cases. Then the bridge’s risks are evaluated according to the results calculated which provide a reference for design of similar project.

scholarly journals Platform for dynamic tests: preliminary studies, design and construction

2013 ◽  
Vol 6 (1) ◽  
pp. 55-74 ◽  
Author(s):  
J. E. Campuzano ◽  
R. de Castro ◽  
S. Ávila ◽  
G. Doz
Keyword(s):  
Natural Frequencies ◽  
Limit State ◽  
Physical Space ◽  
Dynamic Responses ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Dynamic Tests ◽  
Short Columns ◽  
Brazilian Standard ◽  
Design And Construction

This paper is about the design and construction of a platform for dynamic tests especially with people jumping, walking, etc. Initially it was tried to find out projects already implemented in platforms and dynamic tests and to study the loads produced by movement of people on slabs and the structural response to these loads. The limits established by different standards have been also studied for these dynamic responses, taking into account the ultimate limit state, as well as the structure in service, since the human body is very sensitive to structural vibrations. Parametric studies were performed considering various configurations of slabs (different spans, thicknesses and conditions of support) have been done, looking for a configuration that could have natural frequency close to the frequencies of the human loads. The slab should have dimensions compatible with the available physical space, fundamental frequency below 5 Hz and maximum immediate deflection compatible with the indications of the Brazilian standard NBR6118: 2007. Based on these criteria was chosen a rectangular structure consists of a solid reinforced concrete rectangular slab studded in two opposite edges of steel beams with shear connectors type U. The other two edges are free. The steel beams supporting the slab, in turn, are supported on eight metal profiles (two in each corner of the slab) that are supported on two to two short columns of steel profile H. Profiles U in steel are welded to four columns, forming a horizontal frame. Numerical analysis of the dynamic test platform have been performed for free and forced vibration, for obtaining the natural frequencies and corresponding vibration modes, considering the self-weight of the structure and the load that simulates people's weight. After obtaining a structural configuration that fulfilled the stipulated requirements, the design of the slab taking into account the recommendations of the Brazilian standard NBR6118: 2007. The platform was built and has been done a preliminary experimental study to obtain the first natural frequencies.

Influence of the Opening’s Position on Seismic Performance of Autoclaved Aerated Concrete Composite Wall with Core Columns

2012 ◽  
Vol 446-449 ◽  
pp. 767-770
Author(s):  
Hui Ge Wu ◽  
Ji Hua Chen ◽  
Jie Gu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Seismic Performance ◽  
Load Capacity ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Finite Element Software ◽  
Autoclaved Aerated Concrete ◽  
Composite Wall ◽  
Aerated Concrete

To study the seismic performance of autoclaved aerated concrete (AAC) block masonry composite wall with reinforced concrete (RC) columns, a non-linear finite element analysis has been carried out for the walls with openings using the finite element software ABAQUS. First results of finite element analysis were verified with experiment results of full-scale specimen. And then the effect of the opening’s position on seismic performance was studied with finite element analysis. The result indicates that the ultimate load capacity and ultimate displacement are both increased with the upward and outward movement of the openings.

Failure of a linear Voussoir arch: a laboratory and numerical study

1992 ◽  
Vol 29 (2) ◽  
pp. 188-194 ◽  
Author(s):  
B. Stimpson ◽  
M. Ahmed
Keyword(s):  
Numerical Study ◽  
Progressive Failure ◽  
Load Capacity ◽  
Failure Process ◽  
Physical Models ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Underground Openings ◽  
Physical Model Tests ◽  
Discrete Crack

The design of underground openings in horizontally layered strata on the basis of classical linear arching theory assumes the ultimate load capacity of the roof is limited by crushing or compressional failure at the centre of the arch or at the abutments. In this study, physical model tests on limestone, granite, and potash beams revealed a progressive failure mechanism dominated by discrete tensile fracturing, a quite different failure process to that assumed by classical theory. Subsequently, discrete crack propagation finite element analysis successfully simulated the failure mechanisms observed in the physical models. Key words : rock mechanics, underground design, roof stability, Voussoir arch, fracture.

scholarly journals Structural analisys of concrete pre-stressed reservoirs for sludge fermentation – water waste treatment plant bucharest – glina. numerical fem assessment of the structural response for static in-duty loads

2013 ◽  
Vol 9 (1) ◽  
pp. 42-58
Author(s):  
Tudor Bugnariu
Keyword(s):  
Waste Treatment ◽  
Numerical Models ◽  
Limit State ◽  
Treatment Plant ◽  
Structural Response ◽  
Soil Mass ◽  
Ultimate Limit State ◽  
Element Analysis ◽  
Waste Treatment Plant ◽  
Water Waste

Abstract The paper refers to a structural finite element analysis on the reservoirs for sludge fermentation subjected to static in-duty loads, at Glina Water Waste Treatment Plant. The purpose was to assess the stress and deformation states in subsequent erection and service conditions, to verify the design provisions and to emphasize the sensitivities, for a structure which was designed in the ‘80s based on analytical procedures. The results obtained on the numerical models highlight the importance of the soil-structure interaction, in peculiar the one influenced by the soil mass deformability, on the overall structural response. Based on the calculated stresses, all structural components were verified according to the actual design codes at the ultimate limit state and the service limit state (water tightness/crack emergence).

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