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.

Load-Carrying Capacity of Timber Structure Bolt Connection Subjected to Double Unequal Shears

2015 ◽  
Vol 752-753 ◽  
pp. 711-714 ◽  
Author(s):  
Josef Musílek ◽  
Karel Kubečka
Keyword(s):  
Carrying Capacity ◽  
Limit State ◽  
Thin Plates ◽  
Ultimate Limit State ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Timber Member ◽  
Connection Type ◽  
Bolt Connection ◽  
Ultimate Limit

The paper deals with load-carrying capacity of bolted connections subjected to unequal double shears with thin plates as outer members and inner timber member. There are derived equations which describe the load-carrying capacity of this connection type in the ultimate limit state.

Modelling and Statistical Approaches to Lateral-Torsional Buckling

2014 ◽  
Vol 969 ◽  
pp. 259-264
Author(s):  
Zdenek Kala ◽  
Jan Valeš
Keyword(s):  
Carrying Capacity ◽  
Limit State ◽  
Random Effect ◽  
Ultimate Limit State ◽  
Load Carrying Capacity ◽  
Lateral Torsional Buckling ◽  
Random Load ◽  
Torsional Buckling ◽  
Load Carrying ◽  
Ultimate Limit

Some particular and selected problems aimed at ultimate limit state and probability-based studies pertaining to lateral-torsional buckling of steel beams are described. Stochastic analysis of the ultimate limit state of a slender member IPE220 under bending was elaborated. The values of non-dimensional slenderness for which the statistical characteristics of random load-carrying capacity are maximal were determined. The stochastic computational model was created in the programme ANSYS. Geometric nonlinear solution was employed. In the conclusion of the article, the question of the random effect of the initial rotation of the cross-section on the load-carrying capacity is discussed.

Mechanical properties of confirmat screws corner joints made of native wood and wood-based composites

2019 ◽  
Vol 105 ◽  
pp. 76-84
Author(s):  
NADEŽDA LANGOVÁ ◽  
PAVOL JOŠČÁK
Keyword(s):  
Mechanical Properties ◽  
Carrying Capacity ◽  
Limit State ◽  
Calculated Data ◽  
Statistical Processing ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Characteristic Values ◽  
State Method

Mechanical Properties of Confirmat Screws Corner Joints Made of Native Wood and Wood-Based Composites. The aim of this investigation was to design and determine the mechanical properties of confirmat screws corner joints made of native wood and wood-based composites. The objective of the study was to ascertain the stiffness and load carrying capacity of joints that differed in the diameter and length of confirmat type screw, as well as in the kind of materials. The results include statistical processing of measured and calculated data, and evaluation of the influence of selected factors on mechanical properties. The results are applied to the calculation of the characteristic values of the properties and to the determination of the equations for their calculation for other values of the selected factors. The characteristic values are used for the evaluation of the joints according to the limit state method.

Investigation of Ultimate Limit State Safety Margins in the Structural Design Rules

2017 ◽  
Author(s):  
Kristoffer Lofthaug ◽  
Lars Brubak ◽  
Åge Bøe ◽  
Eivind Steen
Keyword(s):  
Finite Elements ◽  
Safety Factor ◽  
Limit State ◽  
Load Level ◽  
Structural Safety ◽  
Ultimate Limit State ◽  
Structural Members ◽  
Safety Margins ◽  
Non Linear ◽  
Ultimate Limit

A study to document the Ultimate Limit State (ULS) safety margins built into the DNV GL rules for Bulk and Tanker is presented. Critical structural members were identified together with the load level at which these members start to develop permanent buckling sets exceeding normal fabrication tolerances. These critical load levels are then compared with the local ULS rule strength limits in order to have a measure for the structural safety margins and hull redundancy. Non-linear finite element (NFLE) analyses were performed to estimate the structural response for different focus areas (critical structural members). Typically, critical members in bottom, deck, transverse bulkhead and hopper were chosen. Cargo hold models were developed both with linear finite elements, [1,2] and non-linear finite elements, [3]. In the non-linear FE analysis, the structural safety factor for ULS was defined as the load level giving permanent plastic deformation equal to the permissible distortion (production tolerances) for structural members. The non-linear FE results were compared with the maximum permissible load level with respect to buckling and yielding according to DNV GL Ship rules [1] inclusive Common Structural Rules for BC&OT (CSR) [4]. The structural safety factor shows a typical value of 1.2–1.4, and for most cases the plate is governing dimensioning structural member. This study has identified significant structural safety margins, typically 20–40% above rule acceptance level for typical highly utilized local areas in Bulk and Tanker hulls. It is to be noted that global Hull Girder Capacity is not addressed in present paper.

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.

Evaluation of Uncertainties in Loadings on Offshore Structures due to Extreme Environmental Conditions

1993 ◽  
Vol 115 (4) ◽  
pp. 237-245 ◽  
Author(s):  
R. G. Bea
Keyword(s):  
Environmental Conditions ◽  
Epistemic Uncertainty ◽  
Limit State ◽  
Offshore Structures ◽  
Ultimate Limit State ◽  
Mackenzie Delta ◽  
Loading Effects ◽  
Load Effects ◽  
Available Information ◽  
Ultimate Limit

This paper summarizes results from a Canadian Standards Association (CSA) sponsored study of the uncertainties associated with extreme (1000 to 10,000-yr return periods) environmental loadings acting on offshore structures (Bea, 1991). The evaluations of the loadings addressed loading effects that resulted from dynamic and nonlinear interactions of the structures. Loading uncertainties were organized and characterized in two categories: 1) inherent randomness (aleatory uncertainty), and 2) analytical variability (epistemic uncertainty). The study addressed the global ultimate limit state performance of three structures designed according to the provisions of the draft CSA guidelines (1989a, 1989b) for offshore structures: 1) a concrete Gravity Base Structure (GBS) located off the East coast of Canada (Hibernia), 2) a steel pile template located on the Scotian Shelf off Sable Island, and 3) a caisson retained island located in the Mackenzie Delta area of the Beaufort Sea (Amuligak). The results of this study indicate that, based on presently available information and data, it is often not possible to develop unambiguous characterizations of uncertainties. The different technical communities that background environmental conditions and forces (storms, earthquakes, ice) recognize and integrate these uncertainties into loading characterizations in different ways. In many cases, major sources of uncertainty are not included in probabilistic characterizations. Because of the needs for design code information sensitivity and consistency in demonstrating compliance with target reliability goals, there is a need for well-organized and definitive evaluations of uncertainties in extreme environmental loadings and load effects (Bitner-Gregersen et al., 1993).

scholarly journals Software implementation of section class and resistance calculation for general loading case

2021 ◽  
Vol 64 (3) ◽  
pp. 159-164
Author(s):  
Tanja Nožica ◽  
Đorđe Jovanović ◽  
Drago Žarković
Keyword(s):  
Cross Section ◽  
Limit State ◽  
Neutral Axis ◽  
Software Implementation ◽  
Ultimate Limit State ◽  
The Matrix ◽  
Loading Case ◽  
Steel Sections ◽  
Ultimate Limit ◽  
Steel Design

In this paper, the problems arising in implementation of the cross-section class and resistance according to Eurocode, especially for classes 1 and 2 of the steel sections, are presented for general loading case. As Eurocode assumes full plastification of the section, regardless of corresponding strain in the material, it is inevitable to find the position of the plastic neutral axis for ultimate limit state of the section. But, for this purpose, one cannot use the Eurocode's expressions for section resistance. Moreover, solution and strategies used in the steel design module of the Matrix 3D are presented in the paper.

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 Buckling of Rectangular Isolated R.C. Columns: Closed-form Approximation for Interaction Domains

2013 ◽  
Vol 7 (1) ◽  
pp. 129-137 ◽  
Author(s):  
Domenico Raffaele ◽  
Giuseppina Uva ◽  
Francesco Porco ◽  
Andrea Fiore
Keyword(s):  
Closed Form ◽  
Limit State ◽  
Ultimate Limit State ◽  
Axial Loads ◽  
Practical Utilization ◽  
Load Carrying ◽  
Steel Bars ◽  
Interaction Domains ◽  
Term Creep ◽  
Ultimate Limit

Interaction domains for the buckling of isolated R.C. columns are an efficient and versatile instrument for the assessment of the resistance at Ultimate Limit State, and allow the optimization of the structural geometry and reinforcement ratio. The paper presents the procedure for deriving interaction domains for rectangular symmetrically reinforced columns, providing a detailed analysis of the load-carrying capacity for various classes of concrete and reinforcement steel bars. Domains have been obtained according to the model-column method, taking into account the uncertainties both in geometry and in the position of axial loads. Effects related to short-term creep are ignored. In order to facilitate the practical utilization, the generic domain has been approximated by a two-branch curve, parabolic and elliptic. The first-one is related to the collapse dominated by axial load, and the second one to flexural crisis. This approximation leads to simple closed-form expressions, particularly suitable for engineering preliminary design.

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