Review of analysis methods for inelastic design of steel semi-continuous frames

An equivalent stiffness approach for modelling the behaviour of compression members according to Eurocode 3

“…The model using both the first order and the second order stress-strain relationships allows for the evaluation of the imperfect element equilibrium path within the concept of divergence instability, and is therefore suitable for considerations of the global effect of imperfections on the axial behaviour of real elements. When both models are simultaneously applied in structural analysis, such an analysis falls in the category of advanced analysis based on the Continuous Stiffness Degradation method (CSD method, see Gizejowski et al [10]) and is able to capture the effects associated with the prediction of the load-deflection characteristic and the ultimate load of imperfect frames and trusses.…”

“…(2) can be notionally regarded as the factor applied to the modulus of elasticity in the elastic critical load equation. When the member is subjected to flexural buckling, the design value of the critical load can be written down as follows, Gizejowski et al [10]:…”

“…It can be seen that for all the calibrated buckling curves they are within the limiting curves and they are very close to the original European curves; therefore they are also close to those predicted by model B of the present study. This is a very important feature of the developed modelling that facilitates its future application in the Continuous Stiffness Degradation method (CSD method, see Gizejowski et al [10]) of advanced analysis that shall comply with the reliability level adopted in Eurocode 3: Part 1-1 [4]. The advantage of the presented new formulation of European buckling curves is that it can be directly used in the prediction of the equivalent axial stiffness and the axial stiffness degradation function corresponding to real structural elements, imperfections of which conform with those adopted in Eurocode 3: Part 1-1 [4].…”

Validation of Csd Advanced Analysis of Braced Frame Responses Using Subframe Experimental Investigations

“…Over the last two decades, research on direct design methods based on advanced analysis of semi-continuous steel framing has been taking place in Poland, starting in [9] with the Chen-Kim RPH version of advanced analysis which then evolved towards the CSD version [10] of which the author of this paper has been the principal investigator. The review of different analysis methods for steel framework design was presented in [11,12], including those concerning advanced analysis. The major differences between CSD advanced analysis and its Chen-Kim RPH counterpart arose from the application of: a) the continuous stiffness degradation concept used for both frame and truss members treated as imperfect elements without an explicit predefinition of the boundary threshold between the elastic and inelastic ranges of member behaviour, b) the definition of force state parameter ĮM-N as the ratio of actual end section moment MEd,i or MEd,k to MN,Rk as the plastic section resistance reduced with regard to actual axial force NEd in the member, c) the utilization of a more precise force-deformation characteristic then those used earlier for the reproduction of the real behaviour of brace elements in the form of an equivalent truss member (i.e.…”

13.18: Advanced analysis of braced steel frames: Modelling accounting for the post‐limit behaviour of compressed angle braces

“…Different approaches to the stability analysis and design of structural steel systems are summarized in [1,2,3,4] in reference to design tradition in North America, Australia and Europe. Conventional geometrically linear methods of global analysis, elastic LA or inelastic MNA, are applied in indirect design of frames being not sensitive to the second order sway effects.…”