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Steel construction highlights

Steel construction highlights. A complete steel solution in Scia Engineer. Overview. True Analysis – Analysis and structural model in parallel Implementation of EN1993 Built-up welded sections Fire resistance AutoDesign – Optimisation 2 nd order lateral torsional buckling

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Steel construction highlights

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  1. Steel construction highlights A complete steel solution in Scia Engineer

  2. Overview • True Analysis – Analysis and structural model in parallel • Implementation of EN1993 • Built-up welded sections • Fire resistance • AutoDesign – Optimisation • 2nd order lateral torsional buckling • ArcelorMittal Cellular Beams (ACB) • Steel connection

  3. True Analysis – Analysis and structural model in parallel • Work in parallel on the analysis model for the calculation part and on the structural model for the generation of drawings & connections. • Priority rules, excentricities, gaps can be added to the analysis model. • Goal: connection design, automatic generation of overview (GA) drawings and connection detail, link with CAD software.

  4. True Analysis – Analysis and structural model in parallel

  5. Implementation of the Eurocodes • Complete & reliable check of members & connections according to EN1993 • Complete solution for the steel construction: combinations, wind & snow loads, check & optimisation of members & joints, fire resistance, composite design, etc

  6. Steel code check according to EN1993

  7. Globalapproach • Stabilityanalysis: • globalstability • αcritical • decision of 1st or 2nd Order calculation

  8. Global approach • Elasticanalysis • αcritical> 10 => 1st Order Calculation • bucklinglength is basedonglobalbucklingmode = equivalent column method • path a

  9. Global approach • αcritical< 10 => 2nd Order Calculation • input of Global Imperfections = equivalent swaymethod • path 2a

  10. Global approach • Global and BowImperfections • path 2c • path 3

  11. 1st Order Calculation • α_critical > 10 • User has to do a Stress and Stability check of the structure • Stress check • Classificationoneveryintermediarysection: class1 , class2, class3 or class4 • Stress check at everyintermediarysectionwithcorrespondingclassification • Stabilitycheck • The criticalsectionclassification over the member is used to perform the stability check • Flexuralbuckling, torsionalbuckling, lateraltorsionalbuckling, interaction check, battenedcompressionmembers

  12. 2nd Order Calculation • α_critical < 10 (elasticanalysis) • Global Imperfection (P – Δ –effects) • Bucklinglengthcanbe taken equal to system length (= buckling factor is 1) • User has to perform a full Stress and StabilityCheck • Path 2a • Global and Local (Bow) Imperfections (P – Δ and P – δ –effects) • Bucklingcheck is alreadyincorporated in the LocalImperfection • OnlyStress and LTB check has to beperformed • Path 2c

  13. 2nd Order Calculation • Global Imperfection (P – Δ –effects) • Local (Bow) Imperfections (P – δ-effects)

  14. Graphical presentation of imperfections

  15. Calculation of buckling factors • Automaticcalculationusing General Formulabasedon • System lengths • Sway/ non-sway • VARH-profiles • Crossingdiagonals • LTA buckling system • User input of buckling factor orbucklinglength • Calculation of buckling factors usingStabilityAnalysis

  16. Calculation of buckling factors

  17. Calculation of buckling factors • General Formula:

  18. Buckling factors using Stability Analysis

  19. Buckling factors using Stability Analysis

  20. Buckling factors using Stability Analysis

  21. Steel Setup • 2nd Order calculation: • onlysection check and LTB check • IfMcrcanbecalculated in • 2nd Order • only a section check has to be • performed

  22. Steel code check according to EN1993

  23. Full Example • Calculation of α_critical • 1st Order Calculation: full check • 2nd Order Caclution: • Global imperfectionsaccording to EN1993 • Localimperfectionsaccording to EN1993

  24. Interaction formula EC-EN • Adaption of the interactionformulaforcombinednormal and flexuralforces •  Maximalmoments are taken

  25. Interaction formula EC-EN

  26. Additional steel data • Member buckling data • Lateral Torsional Buckling restraints

  27. Additional steel data • Diaphragms • Stiffeners

  28. Built-up welded sections • With the rising price of steel, built-up sections become more & more interesting with the gain of steel weight that they allow • Scia Engineer supports all possible built-up section, tapered or not, including slender webs (class 4) with the calculation of effective section properties • The optimisation (AutoDesign) is carried out with user-controlled parameters and methods

  29. Fire resistance • Fire resistance is always a tricky point for steel structures • It is supported in Scia Engineer according to the methods in the Eurocode 3 • All the checks are done, under the various possible temperature curves (ISO, petrol fire, natural fire, etc.) and protection types (none, paintings, gypsum) and allow to guarantee the desired fire resistance at 30, 60 mins etc • Possibility to input a self defined Time/Temperature curve

  30. Fire resistance

  31. 2ndorderlateraltorsionalbuckling • 2nd Order Analysis • Applications: • Calculation of Mcrfor non standardsections • 2nd Order analysisincludingwarpingeffects • Diaphragms are calculatedoncompression and tensionflange • LTB restraintsoncompressionantensionflange • Exact LTB-analysisfor profiles subjected to torsion (e.g.: channel –sections)

  32. 2nd order lateral torsional buckling • For complex cases (tension flanges restrained by the roof, special support conditions, non-symetrical sections), the formulas given in the codes are not applicable • Scia Engineer has a specific calculation module for the critical LTB moment Mcr using 7 DOF beam elements for Euler stability or 2nd order calculation

  33. 2nd order lateral torsional buckling • Mcr calculation in 2nd Order including warping effects: • LTB does not need to be checked anymore

  34. AutoDesign – Optimisation • Global optimisation or by beam families (profiles) • The optimum sections is proposed after a code check (stresses, buckling, LTB, etc) • Either in a full catalogue or a reduced list • As well the rolled profiles as the built-up sections or any user-defined section can be optimised using simple or advanced criterias

  35. Global Autodesign

  36. Global Autodesign

  37. ArcelorMittal Cellular Beams (ACB) • Triple advantadge of aesthetics, holes for technical pipes and large spans • Cellular beams are more & more used in industrial buildings, parkings, etc • Scia Engineer incorporates the design of these beams according the the Eurocode provisions • The deformation is calculated taking into account the reduced properties near the openings.

  38. Steel connections

  39. Steel connections • Steel connections: bolted, welded, beam-column, splice, column footing, floor connection, etc • Fixed, pinned and semi-rigid connections • Takes into account the real stiffness of the joint when re-analyzing the structure • Expert system for the search of an optimum connection in the library • Detailed drawing • 100% integrated to the analysis & structural model

  40. Steel connections CONTENTS: • Connection types • Analysis types and Geometric types • Supported cross-sections • Column-beam joints • Moment-Rotation characteristic • Resistance properties • Stiffness properties • Ductility classes • Special features

  41. Steel connections CONNECTION TYPES: • Rigid connections: • Transfer of bending moment • Not always completely rigid • Stiffness is calculated by Scia Engineer • Low stiffnesses have to be taken into account • Pinned connections: • No transfer of bending moment

  42. Steel connections: SUPPORTED TYPES OF CONNECTIONS Analysis types • Beam-to-column connections : Bolted endplate + welded connections (knee, T, cross - with continuous beam or continuous column) • Beam-to-beam connections : Endplate type beam splice (plate-to-plate connection). • Column bases : Bolted base plate connection shear iron, frange wideners

  43. Steel connections: SUPPORTED TYPES OF CONNECTIONS

  44. Steel connections: SUPPORTED CROSS-SECTIONS

  45. Frame connect: Column-beam joints Moment-rotation characteristic General procedure: Component method to determine stiffness and resistance • Identification of the active components • Evaluation of S and fi for each component • Assembly of all the components

  46. Frame connect: Column-beam joints

  47. Frame connect: Column-beam joints Resistance properties • Equivalent T-stub: analysis of the endplate bending and the column flange bending or bolt yielding  3 possible failure modes (picture) • Use of national code: DIN, ENV, EN1993 and BS: used for the capacities of the Underlying steel parts Other codes: EC3

  48. Frame connect: Column-beam joints Stiffness properties • The component stiffness For a column base: • The stiffness assembly - Sj,ini is derived from elastic stiffness of the components - Represented by a spring - Spring components are combined in a spring model

  49. Frame connect: Column-beam joints

  50. Frame connect: Column-beam joints • Classification on stiffness • The required stiffness: Sj,app = fi y * n  Sj,low <= Sj,ini <=Sj,upper  Sj,ini is conform with the applied stiffness in the analysis model

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