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عنوان فارسی مقاله:
ستون های فلزی بلند و باریک: چگونه آنها توسط عیوب و تولید بندهای سختی تحت تاثیر قرار می گیرند
عنوان انگلیسی مقاله:
Slender steel columns: How they are affected by imperfections and bracing stiffness
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Structural imperfections are critical for determining the behavior of slender structural elements and their bracing systems. These imperfections include construction tolerances, geometrical deviations, residual stresses, load eccentricities and material deficiencies. The numerical modeling of some of the aforementioned imperfections can be cumbersome in design. For example, the modeling of residual stresses would likely require the use of either shell or solid elements (resulting in complex models). Moreover, the code does not specify a geometric imperfection to be used if the residual stresses were to be handled separately. Accordingly, the geometrical imperfections used in design are normally larger than the actual (measurable) geometrical deviations, so as to be able to account for the effect of all imperfections. The important characteristics of a bracing system include its stiffness and its strength properties. Different in-plane bracing methods include discrete (as examined in this study), continuous, relative and lean on (as defined in Galambos et al. [1]), see Fig. 1. In 1958, Winter [2] presented a simple yet powerful rigid link model employed for calculating the strength and stiffness requirements of bracings. This method can be used in particular for calculating the fullbracing (ideal stiffness) requirement. This requirement represents a conservative limit for the required bracing stiffness that is needed in order to achieve buckling between successive bracings. According to this model, a column can be braced at one or more points. Winter's rigid link model was later extended by Yura [3] to allow for cases in which less than full bracing is provided. The rigid link model can also account for initial imperfections, making the study of bracing forces and thus the strength requirements of the bracings possible. While simplified approaches such as the rigid link model are possible, analytical solutions can in some cases also be derived; see e.g. Timoshenko et al. [4] regarding the concept of buckling capacity when less than full bracing is provided. For derivation of the full bracing requirement of a sway prevented column with one intermediate bracing, see e.g. Galambos et al. [1]. The bracing force for a varying applied load, was derived by Trahair [5]. Even in simple cases, however, such as that of a column with only one intermediate bracing, closed-form solutions are rather involved and may not be as practical as ones based on a rigid link model. In the case of more complicated systems, closed-form solutions may not even exist. Since the rigid link model usually assumes equally spaced bracings, Plaut et al. [6–8] in several studies analyzed the implications of having unsymmetrically spaced bracings. It was found that no ideal stiffness could be defined if the bracings are spaced unsymmetrically. This was due to the fact that the displacements at the bracing points can be suppressed only if there is perfect symmetry, i.e. equal spans. Theoretically, this means that there will always be an additional elastic buckling capacity if the bracing stiffness would be increased (see for instance Mehri et al. [9] who thouroghly analyzed this case). Practically, however, a “full bracing requirement” can still be said to exist even for the unsymmetrical case; i.e. when the stiffness of the bracing tends to a value that generates a buckling capacity that would be obtained if infinitely rigid bracings were assumed.
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[PDF]CHAPTER 3. COMPRESSION MEMBER DESIGN 3.1 ... https://www.egr.msu.edu/~harichan/classes/ce405/chap3.pdf Note that the steel yield stress was irrelevant for calculating this buckling .... However, if the column section is made of thin (slender) plate elements, then. [PDF]Design of Slender Columns https://www.tcd.ie/civileng/local/notes/Dermot.ODwyer/4A6/Slender.pdf When a stocky column (i.e. one that is not very slender, where slenderness is defined .... its maximum and the tensile strain in the steel is at its yield point. 0.0035. [PDF]Slender Columns - nptel nptel.ac.in/courses/105105104/pdf/m10l27.pdf explain the behaviour of slender columns loaded concentrically,. • explain the ... (i) the development of high strength materials (concrete and steel),. (ii) improved ... Design of Locally Slender Structural Steel Columns | Journal of ... ascelibrary.org/doi/abs/10.1061/(ASCE)ST.1943-541X.0000889 by M Seif - 2013 - Cited by 4 - Related articles The primary objective of this paper is to evaluate and compare design methods for locally slender steel columns. Three design methods utilized for such ... Design of Locally Slender Structural Steel Columns - ASCE Library ascelibrary.org/doi/pdf/10.1061/(ASCE)ST.1943-541X.0000889 by M Seif - 2013 - Cited by 4 - Related articles Jun 3, 2013 - Abstract: The primary objective of this paper is to evaluate and compare design methods for locally slender steel columns. Three design. [PDF]Chapter 4 Design of Slender Columns by.genie.uottawa.ca/.../CHAPTER%204%20-%20SLENDER%20COLUMNS%20-%2... moments generated in a slender column by P-Δ effects. Slender columns resist lower ..... (Note that the required steel ratio of 3% is slightly higher that the 2.5% ... [PDF]Slenderness Effect www.ce.memphis.edu/6136/PDF_notes/C_Column_interaction_Slender2.pdf A plot of the buckling load vs. the slenderness ratio, a so-called column curve (Figure ... High strength steel and concrete make slender columns more common. Searches related to Slender steel column slenderness ratio of column formula slender column design example slender column definition difference between short column and long column pdf major axis and minor axis of column steel column design example compression members in steel structures long column design pdf
