• Title/Summary/Keyword: flexural, buckling

Search Result 192, Processing Time 0.02 seconds

Moment Magnifier Method for RC Flat Plate Subject to Combined Axial Compressive and Floor Load (면내 압축력을 받는 플랫 플레이트 슬래브에 대한 모멘트 증대법)

  • Park, Hong-Gun
    • Magazine of the Korea Concrete Institute
    • /
    • v.11 no.1
    • /
    • pp.243-254
    • /
    • 1999
  • This paper presents a numerical study for developing the moment magnifier method that is applicable to RC flat plates subject to combined axial compressive and floor load. For the nonlinear finite element analysis, a computer program addressing material and geometric nonlinearities was developed. The flat plates to be studied are designed in accordance with the Direct Design Method in Korean Building Code for Structural Concrete. This paper proposes the buckling force and the moment magnification factor for the flat plate under the governing load condition that is the combined vertical and subsequently applied uniaxial compressive load. The buckling force is defined with two ingredients: the buckling coefficient and the effective flexural rigidity. Parametric studies are performed to investigate variations of the buckling coefficient and the effective flexural rigidity. Based on the numerical results, this paper provides the design values of the buckling coefficient and the effective flexural rigidity, and the design procedure for the moment magnifier method.

Critical Loads of Eccentrically Loaded Struts with Thin-Walled Open Sections (편심하중을 받는 박벽개단면 압축재의 임계하중)

  • 나영진;이수곤
    • Computational Structural Engineering
    • /
    • v.9 no.4
    • /
    • pp.135-140
    • /
    • 1996
  • Single angle or channel with thin-walled open section can be used as compression member for example as web member in truss. In this case the inevitable eccentricity due to fabrication is commonly neglected in structural design. However eccentricity effect should be considered in the member design, especially in case of compression member. The critical loads of compression members that buckle by twisting or by a combination of bending and twisting are to be determined by solving governing differential equations. In this paper, the investigations are limited to the rolled channels([), equal-leg angles(L), lipped channels(C) and the applied loads are assumed to have some eccentricities.

  • PDF

Flexural behaviour of steel plate-masonry composite beams

  • Jing, Deng-Hu;Cao, Shuang-Yin;Shi, Lei
    • Steel and Composite Structures
    • /
    • v.13 no.2
    • /
    • pp.123-137
    • /
    • 2012
  • Steel plate-masonry composite structure is a newly-developed type of structural technique applicable to existing masonry buildings by which the load-bearing walls can be removed for large spaces. This kind of structure has been used in practice for its several advantages, but experimental investigation on its elements is nearly unavailable in existing literature. This paper presents an experimental study on the flexural behaviour of four steel plate-masonry composite beams loaded by four-point bending. Test results indicate that failure of the tested beams always starts from the local buckling of steel plate, and that the tested beams can satisfy the requirement of service limit state. In addition, the assumption of plane section is still remained for steel plate prior to local buckling or steel yielding. By comparative analyses, it was also verified that the working performance of the beam is influenced by the cross-section of steel plate, which can be efficiently enhanced by epoxy adhesive rather than cement mortar or nothing at all. Besides, it was also found that the contribution of the encased masonry to the flexural capacity of the composite beam cannot be ignored when the beam is injected with epoxy adhesive.

Slenderness effects on the simulated response of longitudinal reinforcement in monotonic compression

  • Gil-Martin, Luisa Maria;Hernandez-Montes, Enrique;Aschheim, Mark;Pantazopoulou, Stavroula J.
    • Structural Engineering and Mechanics
    • /
    • v.23 no.4
    • /
    • pp.369-386
    • /
    • 2006
  • The influence of reinforcement buckling on the flexural response of reinforced concrete members is studied. The stress-strain response of compression reinforcement is determined computationally using a large-strain finite element model for bars of varied diameter, length, and initial eccentricity, and a mathematical expression is fitted to the simulation results. This relationship is used to represent the response of bars in compression in a moment-curvature analysis of a reinforced concrete cross section. The compression bar may carry more or less force than a tension bar at a corresponding strain, depending on the relative influence of Poisson effects and bar slenderness. Several cross-section analyses indicate that, for the distances between stirrups prescribed in modern concrete codes, the influence of inelastic buckling of the longitudinal reinforcement on the monotonic moment capacity is very small and can be neglected in many circumstances.

Elastic Stability of Thin-Walled Arches subjected to Uniform Bending - Linear Bending Normal Strain Distribution -

  • Ryu, Hyo-Jin;Lim, Nam-Hyoung;Lee, Chin-Ok
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.9 no.2
    • /
    • pp.11-15
    • /
    • 2009
  • This paper is concerned with the elastic buckling of thin-walled arches that are subjected to uniform bending. Nonlinear strain-displacement relations with the initial curvature are substituted into the second variation of the total potential energy to obtain the energy equation including initial curvature effects. The approximation for initial curvature effects that the bending normal strain distribution is linear across the cross section is applied consistently in the derivation process. The closed form solution is obtained for flexural-torsional buckling of arches under uniform bending and, it is compared with the previous theoretical results.

Flexural performance of cold-formed square CFST beams strengthened with internal stiffeners

  • Zand, Ahmed W. Al;Badaruzzaman, W.H. Wan;Ali, Mustafa M.;Hasan, Qahtan A.;Al-Shaikhli, Marwan S.
    • Steel and Composite Structures
    • /
    • v.34 no.1
    • /
    • pp.123-139
    • /
    • 2020
  • The tube outward local buckling of Concrete-Filled Steel Tube (CFST) beam under high compression stress is still considered a critical problem, especially for steel tubes with a slender section compared to semi-compact and compact sections. In this study, the flexural performance of stiffened slender cold-formed square tube beams filled with normal concrete was investigated. Fourteen (14) simply supported CFST specimens were tested under static bending loads, stiffened with different shapes and numbers of steel stiffeners that were provided at the inner sides of the tubes. Additional finite element (FE) CFST models were developed to further investigate the influence of using internal stiffeners with varied thickness. The results of tests and FE analyses indicated that the onset of local buckling, that occurs at the top half of the stiffened CFST beam's cross-section at mid-span was substantially restricted to a smaller region. Generally, it was also observed that, due to increased steel area provided by the stiffeners, the bending capacity, flexural stiffness and energy absorption index of the stiffened beams were significantly improved. The average bending capacity and the initial flexural stiffness of the stiffened specimens for the various shapes, single stiffener situations have increased of about 25% and 39%, respectively. These improvements went up to 45% and 60%, for the double stiffeners situations. Moreover, the bending capacity and the flexural stiffness values obtained from the experimental tests and FE analyses validated well with the values computed from equations of the existing standards.

Analytical study of buckling profile web stability

  • Taleb, Chems eddine;Ammari, Fatiha;Adman, Redouane
    • Structural Engineering and Mechanics
    • /
    • v.53 no.1
    • /
    • pp.147-158
    • /
    • 2015
  • Elements used in steel structures may be considered as an assembly of number of thin flat walls. Local buckling of these members can limit the buckling capacity of axial load resistance or flexural strength. We can avoid a premature failure, caused by effects of local buckling, by limiting the value of the wall slenderness which depend on its critical buckling stress. According to Eurocode 3, the buckling stress is calculated for an internal wall assuming that the latter is a simply supported plate on its contour. This assumption considers, without further requirement, that the two orthogonal walls to this wall are sufficiently rigid to constitute fixed supports to it. In this paper, we focus on webs of steel profiles that are internal walls delimited by flanges profiles. The objective is to determine, for a given web, flanges dimensions from which the latter can be considered as simple support for this web.

Vibration and Stability Characteristics of Cylindrical Panels by the Galerkin Method (Galerkin 해석법에 의한 원통 Panel의 진동 및 좌굴특성)

  • Park, Moon Ho;Park, Sung Jin
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.11 no.4
    • /
    • pp.27-35
    • /
    • 1991
  • This paper presents a numerical analysis procedure and a characteristics for vibration and buckling of the cylinderical panels. The panels with simply-simply or simply-clamped edge supports are subjectes to circumferential compressive or flexural stresses. The differential equations governing vibration and buckling for these panels are derived by using the fundamental differential equation of the Love-Timoshenko and are solved numerically via the Galerkin method. The panel with simply-clamped edge supports is used a trigonometric function or a eigen function of a beam as a trial function and the effects of trial functions on numerical solutions are displayed. Numerical results are presented to demonstrate the effects of the flexural parameters in natural frequencies and coefficients of critical buckling and some typical mode shapes of vibration and buckling are also presented.

  • PDF

Effects of plate slenderness on the ultimate strength behaviour of foam supported steel plate elements

  • Pokharel, Narayan;Mahendran, Mahen
    • Structural Engineering and Mechanics
    • /
    • v.21 no.4
    • /
    • pp.407-422
    • /
    • 2005
  • Plate elements in fully profiled sandwich panels are generally subjected to local buckling failure modes and this behaviour is treated in design by using the conventional effective width method for plates with a width to thickness (b/t) ratio less than 100. If the plate elements are very slender (b/t > 1000), the panel failure is governed by wrinkling instead of local buckling and the strength is determined by the flexural wrinkling formula. The plate elements in fully profiled sandwich panels do not fail by wrinkling as their b/t ratio is generally in the range of 100 to 600. For this plate slenderness region, it was found that the current effective width formula overestimates the strength of the fully profiled sandwich panels whereas the wrinkling formula underestimates it. Hence a new effective width design equation has been developed for practical plate slenderness values. However, no guidelines exist to identify the plate slenderness (b/t) limits defining the local buckling, wrinkling and the intermediate regions so that appropriate design rules can be used based on plate slenderness ratios. A research study was therefore conducted using experimental and numerical studies to investigate the effect of plate slenderness ratio on the ultimate strength behaviour of foam supported steel plate elements. This paper presents the details of the study and the results.

Local and global buckling condition of all-steel buckling restrained braces

  • Mirtaheri, Seyed Masoud;Nazeryan, Meissam;Bahrani, Mohammad Kazem;Nooralizadeh, Amin;Montazerian, Leila;Naserifard, Mohamadhosein
    • Steel and Composite Structures
    • /
    • v.23 no.2
    • /
    • pp.217-228
    • /
    • 2017
  • Braces are one of the retrofitting systems of structure under earthquake loading. Buckling restrained braces (BRBs) are one of the very efficient braces for lateral loads. One of the key needs for a desirable and acceptable behavior of buckling-restraining brace members under intensive loading is that it prevents total buckling until the bracing member tolerates enough plastic deformation and ductility. This paper presents the results of a set of analysis by finite element method on buckling restrained braces in which the filler materials within the restraining member have been removed. These braces contain core as the conventional BRBs, but they have a different buckling restrained system. The purpose of this analysis is conducting a parametric study on various empty spaces between core and restraining member, the effect of friction between core and restraining member and applying initial deformation to brace system to investigate the global buckling behavior of these braces. The results of analysis indicate that the flexural stiffness of restraining member, regardless of the amount of empty space, can influence the global buckling behavior of brace significantly.