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 Combined axial and flexural loads in short reinforced concrete columns in fire: ultimate limit state curves using 500 °C isotherm method

2018 ◽  
Vol 11 (1) ◽  
pp. 163-182
Author(s):  
J. S. SUAZNABAR ◽  
V. P. SILVA
Keyword(s):  
Reinforced Concrete ◽  
Cross Sections ◽  
Limit State ◽  
Concrete Columns ◽  
Ultimate Limit State ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
In Fire ◽  
Ultimate Limit

Abstract Ultimate limit state curves of short reinforced concrete columns in fire situation are going to be presented in this paper. The authors created a code developed in Matlab. It makes a discretization of the cross sections of the columns and calculates the equilibrium integrals of them. The curves were plotted with the code considering the 500 °C isotherm method.

APPLICATION OF UNCERTAINTY ANALYSIS TO STABILITY PROBLEMS OF STEEL-CONCRETE STRUCTURAL MEMBERS

2009 ◽  
Vol 1 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Libor Puklický ◽  
Zdeněk Kala
Keyword(s):  
Epistemic Uncertainty ◽  
Limit State ◽  
Ultimate Limit State ◽  
Load Carrying Capacity ◽  
Structural Members ◽  
Load Carrying ◽  
Steel Sections ◽  
Limit Stress ◽  
Ultimate Limit

The paper deals with the fuzzy analysis of the ultimate limit state of a steel strut with an encased web in compression. The first part of the paper lists presumptions required for the determination of the theoretical load carrying capacity for the column. Stresses in the concrete and steel sections are determined according to the principles of elasticity. The ultimate limit state is given as the limit stress attained in the most stressed section of either the steel or concrete section. A general extended principle, which takes into account the epistemic uncertainty of input parameters, was utilized for the conducted analysis.

scholarly journals Some considerations on shear and torsion in R/C structural members in fire

2018 ◽  
Vol 9 (2) ◽  
pp. 94-107 ◽  
Author(s):  
Patrick Bamonte ◽  
Pietro G. Gambarova ◽  
Nataša Kalaba ◽  
Sergio Tattoni
Keyword(s):  
Limit State ◽  
Ultimate Limit State ◽  
Structural Members ◽  
Zone Method ◽  
Concrete Core ◽  
Content Type ◽  
Dowel Action ◽  
In Fire ◽  
Ultimate Limit ◽  
Fire Conditions

Purpose This study aims to provide a factual justification of the extension to fire conditions of the well-known design models for the calculations of R/C members at the ultimate limit state in shear and torsion. Both solid and thin-walled sections are considered. In the latter case, the little-known topic of shear-transfer mechanisms at high temperature is introduced and discussed. Design/methodology/approach Both the effective-section method and the zone method are treated, as well as the strut-and-tie models required by the analysis of the so-called D zones (discontinuity zones), where heat-enhanced cracking further bears out the phenomenological basis of the models. Findings The increasing role played by the stirrups in shear and by the rather cold concrete core in torsion stand out clearly in fire, while high temperatures rapidly reduce the contributions of such resisting mechanisms as concrete-teeth bending, aggregate interlock and dowel action. Originality/value On the whole, beside quantifying the side contributions of web mechanisms and section core in fire conditions, this study indicates a possible approach to extend to fire the available models on the coupling of shear and bending, and shear and torsion in R/C members.

The relocation of a heritage bridge

2021 ◽  
Author(s):  
Paul Hogesteeger ◽  
Rob Vergoossen ◽  
Marc Bruchner
Keyword(s):  
Cross Sections ◽  
Structural Integrity ◽  
Limit State ◽  
Ultimate Limit State ◽  
Residual Service Life ◽  
History Of ◽  
Pros And Cons ◽  
Remaining Capacity ◽  
Ultimate Limit ◽  
Residual Service

<p>This paper describes the history of a heritage bridge in Amsterdam (The Netherlands) and the efforts made for the relocation of this bridge. Investigations were made to determine the structural integrity of the original elements and structural assessments were done to find the remaining capacity for future use. The Ultimate Limit State for the original elements was investigated. Lateral stability was checked and based on the historical use and the required future use the fatigue loads were calculated for the different cross sections and for critical connections. These calculations showed that a required residual service life of 30 years after relocation was technically possible for this bridge. Some pros and cons for the re-use of this bridge are also discussed.</p>

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.

Determination of Environmental Conditions Relevant for the Ultimate Limit State at an Exposed Aquaculture Location

2017 ◽  
Author(s):  
Pål Takle Bore ◽  
Jørgen Amdahl
Keyword(s):  
Environmental Conditions ◽  
Limit State ◽  
Ultimate Limit State ◽  
Distribution Method ◽  
Wave Data ◽  
Wave Conditions ◽  
One Year ◽  
Ultimate Limit

Methods for determination of environmental conditions relevant for the ultimate limit state at an exposed aquaculture location are proposed. The considered location is in Frohavet, northwest of Trondheim, Norway. Wind, waves and current are considered, but as more severe wave conditions are expected to be the most influential environmental factor when going from sheltered to more exposed locations, particular focus has been given on the description of wave conditions. The estimated long term description of wind and waves are based on 16 year of SWAN hindcast data, where the wave data have been calibrated against one year of in-situ measurements. One month of current measurements were available. The initial distribution method is used to determine the long term distribution of wind and wave conditions. The data fit the applied distributions well, but the sea state characteristics are seen to be highly directional dependent, which is important to take into account. The effect of using only one year of wave data is also investigated, showing that this can lead to significant underestimation of the extreme values. Concepts from the environmental contour line method are applied for determination of sea states corresponding to a given annual probability of exceedance. A deterministic approach from NS 9415 is used to determine the extreme current velocities. Comments on the use of directional criteria for design are also given.

scholarly journals NON-LINEAR ANALYSIS OF SLENDER MASONRY COLUMN SUBJECTED TO BIAXIAL BENDING

2021 ◽  
Vol 61 (2) ◽  
pp. 391-405
Author(s):  
Marek Vokál ◽  
Michal Drahorád
Keyword(s):  
Numerical Study ◽  
Limit State ◽  
Ultimate Limit State ◽  
Beam Model ◽  
Bending Moments ◽  
Biaxial Bending ◽  
Rigid Plastic ◽  
Internal Forces ◽  
Ultimate Limit ◽  
Current Code

The article deals with a method for analysing slender masonry columns. The proposed method uses material and geometric non-linearity. Various stress-strain diagrams can be used: linear, linear-plastic, parabolic-plastic, two various parabolic and rigid-plastic. In all cases, the tensile strength is neglected. The method can be used for analysing the column in accordance with Eurocodes in two ways: SLS (serviceability limit state) and ULS (ultimate limit state). The internal forces are calculated on a general beam model, with imperfections in both directions, which result in two bending moments in two perpendicular planes – biaxial bending. This case is not covered by the current code – Eurocode, even though all columns are more or less loaded in both directions. In this numerical study, using Matlab software, an algorithm was developed for modelling a real 3D case. The results of this study are also compared to the results of laboratory tests of masonry columns.

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