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ETABS Modelling

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The aim of this manual is to give the design application of the basic requirements of EC8 for new concrete and steel buildings using ETABS. This book can be used by users of ETABS modeler. Is not …

The aim of this manual is to give the design application of the basic requirements of EC8 for new concrete and steel buildings using ETABS. This book can be used by users of ETABS modeler. Is not cover all the steps that you have to carry during designing model using ETABS but is a good manual for those who using Eurocodes.

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  • 1. ETABS MODELLINGAUTHOR: VALENTINOS NEOPHYTOU BEng (Hons), MSc March 2013
  • 2. ETABS MODELING ACCORDING TO EUROCODES Step by step procedure and methodology of how you developing a modelusing ETABSStep 1: Specify Material Properties for Concrete 1. Poisson ratio is equal to v = 0 (cracked concrete) and v = 0.2 (un-cracked concrete) as (EN1992-1-1,cl.3.1.3) Table 1: Concrete properties (EN 1992, Table 3.1) C16/20 C20/25 C25/30 C30/37Property Data for concrete (N/mm2) (N/mm2) (N/mm2) (N/mm2)Mass per unit Volume 2,5E-09 2,5E-09 2,5E-09 2,5E-09Weight per unit volume 2,5E-05 2,5E-05 2,5E-05 2,5E-05Modulus of Elasticity 29000 30000 31000 33000Poisson’s Ratio (cracked concrete) 0 0 0 0Coeff. of thermal expansion 10E-06 10E-06 10E-06 10E-06Charact. ConcCyl. Strength, fck 16 20 25 30Bending Reinf. Yield stress, fyk 500 500 500 500Shear Reinf. Yield stress, fyk 500 500 500 500 Figure 1: Concrete properties Valentinos Neophytou BEng (Hons), MSc   Page: 2 ETABS MANUAL  
  • 3. ETABS MODELING ACCORDING TO EUROCODESStep 2: Add frame section for columns Figure 2: Section properties of concrete columnsValentinos Neophytou BEng (Hons), MSc   Page: 3ETABS MANUAL  
  • 4. ETABS MODELING ACCORDING TO EUROCODESStep 3: Add frame section for beams Figure 3: Effective width of beams (EN1992-1-1,cl.5.3.2.1)Interior beamInternal beamsupporting aninternal and anexternal slabExterior beamsupportingcantileverExternal beamno cantilever For practice use beff 1,2 = 0.2lo Valentinos Neophytou BEng (Hons), MSc   Page: 4 ETABS MANUAL  
  • 5. ETABS MODELING ACCORDING TO EUROCODES Figure 4: Section properties of concrete beamsNotes: 1. Property modification factors are used to reduce moment and torsion stiffness due to crack section. Torsional stiffness of the cracked section should be set equal to 10% of the torsional stiffness of the un-cracked section. 2. Unless a more accurate analysis of the cracked elements is performed, the elastic flexural and shear stiffness properties of concrete and masonry elements may be taken to be equal to one-half of the corresponding stiffness of the un-cracked elements (EN1998-1-1,cl. 4.3.1(7)). 3. These modification factor only affect the analysis properties, they do not affect the design properties. Column (Line Beam (Line Slab (Shell element) Wall (Shell element) element) element) I22=I33=0.5 I22=I33=0.5 m11=m12=m22=0.5 m11= m12=m22=0.5 It=0.1 It=0.1 It=0.1 It=0.1Valentinos Neophytou BEng (Hons), MSc   Page: 5ETABS MANUAL  
  • 6. ETABS MODELING ACCORDING TO EUROCODESStep 4: Add Slabs & Walls Figure 5: Section properties of concrete slab Figure 6: Section properties of concrete wallValentinos Neophytou BEng (Hons), MSc   Page: 6ETABS MANUAL  
  • 7. ETABS MODELING ACCORDING TO EUROCODESStep 5: Define Response Spectrum function according to EC8 1. Peak ground acceleration agR=0,25g, 2. Type C or D for building within category of importance I and II, 3. Define two response spectrum cases if the factor q is different in each direction, 4. Modify the existing values of elastic response spectrum case in order to change it into the design response spectrum. Figure 7: Response Spectrum to EC8Valentinos Neophytou BEng (Hons), MSc   Page: 7ETABS MANUAL  
  • 8. ETABS MODELING ACCORDING TO EUROCODES Figure 8: Design spectrum for elastic analysis data PERIOD   ACCELERATION   g   =   9.81   m/sec2   T   Sd(T)   β   =   0.2   -­‐         0.0000   0.0767   Soil  Type   =   C   -­‐   0.0667   0.1150   q   =   1.50   -­‐         0.1333   0.1533   αgR   =   0.10   -­‐   0.2000   0.1917   S   =   1.15   -­‐     0.6000   0.1917   TB   =   0.20   sec         0.8333   0.1380   TC   =   0.60   sec   1.0667   0.1078   TD   =   2.00   sec   1.3000   0.0885   T   =   0.50   sec   1.5333   0.0750               1.7667   0.0651     Data  for  soil  type  -­‐  T  ype  Spectrum  1       2.0000   0.0575     index   Soil  Type   S   TB   TC   TD   3.3333   0.0200     1   A   1   0.15   0.4   2   4.6667   0.0200     2   B   1.2   0.15   0.5   2   6.0000   0.0200     3   C   1.15   0.2   0.6   2     7.3333   0.0200   4   D   1.35   0.2   0.8   2     8.6667   0.0200   5   E   1.4   0.15   0.5   2   10.0000     0.0200                Valentinos Neophytou BEng (Hons), MSc   Page: 8ETABS MANUAL  
  • 9. ETABS MODELING ACCORDING TO EUROCODESStep 6: Define Load Case Figure 8: Dead/Live/WindStep 5: Define Equivalent Static AnalysisEquivalent static analysis can be used if the following case can be met: 1. Ground acceleration: Check seismic zonation map from National Annex 2. Spectrum type 1: 5.5Hz<M (High seismicity areas) 3. Ground type: Normally type B or C can be used (see EN 1998,table 3.1) 4. Lower bound factor for the horizontal design spectrum: 0.2 (EN 1998-1- 1,cl.3.2.2.5(4)P) 5. Behavior factor q: See table 6. Correction factor λ (EN1998-1-1,cl.4.3.3.2.2(1Ρ)) λ=0.85 if T1≤2TC and more than 2 storey λ=1.0 in all other case Valentinos Neophytou BEng (Hons), MSc   Page: 9 ETABS MANUAL  
  • 10. ETABS MODELING ACCORDING TO EUROCODES 7. Regular in elevation 8. Regular in elevation and irregular in plan 9. Fundamental period: T1≤4T_c T1≤2,0s Table 1: Equivalent Static Force Case Load case name Direction and Eccentricity % Eccentricity EQXA X Dir + Eccen. Y 0.05 EQYA X Dir – Eccen. Y 0.05 EQXB Y Dir + Eccen. X 0.05 EQYB Y Dir – Eccen. X 0.05Valentinos Neophytou BEng (Hons), MSc   Page: 10ETABS MANUAL  
  • 11. ETABS MODELING ACCORDING TO EUROCODESStep 6: Define Load Combination for Equivalent lateral force analysisUltimate limit state (ULS)Static case COMBO 1. 1.35DL + 1.5LL COMBO 2. 1.35DL + 1.5WINDX + 1.5 (0.7LL + 0.5 SNOW) COMBO 3. 1.35DL + 1.5WINDY + 1.5 (0.7LL + 0.5 SNOW) COMBO 4. 1.35DL + 1.5LL + 1.5 (0.7WINDX + 0.5 SNOW) COMBO 5. 1.35DL + 1.5LL + 1.5 (0.7WINDY + 0.5 SNOW) COMBO 6. 1.35DL + 1.5LL + 1.5 (0.7SNOW + 0.5WINDX) COMBO 7. 1.35DL + 1.5LL + 1.5 (0.7SNOW + 0.5WINDY) COMBO 8. 1.35DL + 1.5SNOW + 1.5 (0.7LL+ 0.5WINDX) COMBO 9. 1.35DL + 1.5SNOW + 1.5 (0.7LL+ 0.5WINDY) COMBO 10. 1.35DL + 1.5SNOW + 1.5 (0.7WINDX + 0.5LL) COMBO 11. 1.35DL + 1.5SNOW + 1.5 (0.7WINDY + 0.5LL) COMBO 12. 1.35DL + 1.5WINDX + 0.7*1.5(LL+SNOW) COMBO 13. 1.35DL + 1.5WINDY + 0.7*1.5(LL+SNOW) COMBO 14. 1.35DL + 1.5(LL+SNOW) + 0.7*1.5WINDX COMBO 15. 1.35DL + 1.5(LL+SNOW) + 0.7*1.5WINDYSeismic case COMBO 16. DL + 0.3LL + EQXA + 0.3EQYA COMBO 17. DL + 0.3LL + EQXA – 0.3EQYA COMBO 18. DL + 0.3LL - EQXA + 0.3EQYA COMBO 19. DL + 0.3LL - EQXA – 0.3EQYA COMBO 20. DL + 0.3LL + EQYA + 0.3EQXA COMBO 21. DL + 0.3LL + EQYA – 0.3EQXA COMBO 22. DL + 0.3LL - EQYA + 0.3EQXA COMBO 23. DL + 0.3LL - EQYA – 0.3EQXA COMBO 24. DL + 0.3LL + EQXB + 0.3EQYB COMBO 25. DL + 0.3LL + EQXB – 0.3EQYB COMBO 26. DL + 0.3LL - EQXB + 0.3EQYB COMBO 27. DL + 0.3LL - EQXB – 0.3EQYB COMBO 28. DL + 0.3LL + EQYB + 0.3EQXB COMBO 29. DL + 0.3LL + EQYB – 0.3EQXB COMBO 30. DL + 0.3LL - EQYB + 0.3EQXB COMBO 31. DL + 0.3LL - EQYB – 0.3EQXBServiceability limit state (SLS) COMBO 32. DL + LL Valentinos Neophytou BEng (Hons), MSc   Page: 11 ETABS MANUAL  
  • 12. ETABS MODELING ACCORDING TO EUROCODESStep 7: Define Response Spectrum caseModal Response spectrum 1. Independently in X and Y direction, 2. Define design spectrum, 3. Use CQC rule for the combination of different modes (EN1998-1-1,cl.4.3.3.3.2(3)) 4. Use SRS rule for combined the results of modal analysis for both horizontal directions (EN1998-1-1,cl.4.3.3.5.1(21)). 5. Accidental eccentricity of each storey cause of uncertainties locatin of masses have been taken into account 5% (EN1998-1-1,cl.4.3.2). 6. Modal Combination: “Complete Quadratic Combination” (CQC) can be used if the Tj ≤ 0,9 Ti (EN1998-1-1,cl.4.3.3.3.2(3)P). Figure 9: Response Spectrum case Data for EQY& EQXValentinos Neophytou BEng (Hons), MSc   Page: 12ETABS MANUAL  
  • 13. ETABS MODELING ACCORDING TO EUROCODESStep 8: Define Load Combination for modal analysisUltimate limit state (ULS)Static case COMBO 1. 1.35DL + 1.5LL COMBO 2. 1.35DL + 1.5WINDX + 1.5 (0.7LL + 0.5 SNOW) COMBO 3. 1.35DL + 1.5WINDY + 1.5 (0.7LL + 0.5 SNOW) COMBO 4. 1.35DL + 1.5LL + 1.5 (0.7WINDX + 0.5 SNOW) COMBO 5. 1.35DL + 1.5LL + 1.5 (0.7WINDY + 0.5 SNOW) COMBO 6. 1.35DL + 1.5LL + 1.5 (0.7SNOW + 0.5WINDX) COMBO 7. 1.35DL + 1.5LL + 1.5 (0.7SNOW + 0.5WINDY) COMBO 8. 1.35DL + 1.5SNOW + 1.5 (0.7LL+ 0.5WINDX) COMBO 9. 1.35DL + 1.5SNOW + 1.5 (0.7LL+ 0.5WINDY) COMBO 10. 1.35DL + 1.5SNOW + 1.5 (0.7WINDX + 0.5LL) COMBO 11. 1.35DL + 1.5SNOW + 1.5 (0.7WINDY + 0.5LL) COMBO 12. 1.35DL + 1.5WINDX + 0.7*1.5(LL+SNOW) COMBO 13. 1.35DL + 1.5WINDY + 0.7*1.5(LL+SNOW) COMBO 14. 1.35DL + 1.5(LL+SNOW) + 0.7*1.5WINDX COMBO 15. 1.35DL + 1.5(LL+SNOW) + 0.7*1.5WINDYSeismic case COMBO 16. DL + 0.3LL + EQX + 0.3EQY COMBO 17. DL + 0.3LL + EQX – 0.3EQY COMBO 18. DL + 0.3LL - EQX + 0.3EQY COMBO 19. DL + 0.3LL - EQX – 0.3EQY COMBO 20. DL + 0.3LL + EQY + 0.3EQX COMBO 21. DL + 0.3LL + EQY – 0.3EQX COMBO 22. DL + 0.3LL - EQY + 0.3EQX COMBO 23. DL + 0.3LL - EQY – 0.3EQXServiceability limit state (SLS) COMBO 24. DL + LL Valentinos Neophytou BEng (Hons), MSc   Page: 13 ETABS MANUAL  
  • 14. ETABS MODELING ACCORDING TO EUROCODES G+0.3Q+Ex+0.3Ey G+0.3Q+Ex-0.3Ey G+0.3Q-Ex+0.3Ey G+0.3Q-Ex-0.3Ey G+0.3Q+Ey+0.3Ex G+0.3Q+Ey-0.3ExValentinos Neophytou BEng (Hons), MSc   Page: 14ETABS MANUAL  
  • 15. ETABS MODELING ACCORDING TO EUROCODES G+0.3Q-Ey+0.3Ex G+0.3Q-Ey-0.3Ex 1.35G+1.5QValentinos Neophytou BEng (Hons), MSc   Page: 15ETABS MANUAL  
  • 16. ETABS MODELING ACCORDING TO EUROCODESValentinos Neophytou BEng (Hons), MSc   Page: 16ETABS MANUAL  
  • 17. ETABS MODELING ACCORDING TO EUROCODESStep 9: Meshing of slabAssign -> Shell Area -> Area Object Mesh OptionAutomatic meshing option for slab element onlyNotes: 1. The property assignments to meshed area objectets are the same as the original area object. 2. Load and mass assignments on the original area object are appropriately broken up onto the meshed area objects. Valentinos Neophytou BEng (Hons), MSc   Page: 17 ETABS MANUAL  
  • 18. ETABS MODELING ACCORDING TO EUROCODESStep 10: Meshing/Label of wallEdit>Mesh shells and click on theMesh/Quads/Triangles at Intersections with visible grid lines:Assign->Shell/Area->Pier Label or Spandrel Label. Valentinos Neophytou BEng (Hons), MSc   Page: 18 ETABS MANUAL  
  • 19. ETABS MODELING ACCORDING TO EUROCODESStep 11: Define Auto-Line ConstraintSelect area element (slab)->Assign->Shell Are-> Auto-Line ConstraintStep 12: Define mass sourceCombination of the seismic action with other actions (EN 1998-1-1,cl.3.2.4): 1. Define the category of building (EN 1991,Table 6.1), 2. Define the reduce factor (EN 199, Table A.1.1). Table 2: Combination of seismic mass 𝑮 𝒌,𝒋 + 𝝍 𝑬𝒊 𝑸 𝒌,𝒊 (ΕΝ1998-1-1,Eq. 3.17) Combination coefficient for variable action is: 𝜓!" = 𝜙 ∙ 𝜓!! (ΕΝ1998-1-1,Eq. 4.2) Values of φ for calculating 𝝍 𝑬𝒊 (CYS NA EN1998-1-1:2004) Type of Storey φ Variable action Roof 1,0 Categories A- Storeys with correlated occupancies 0,8 C1 Independently occupied storeys 0,5 Categories A- 1.0 F1 Valentinos Neophytou BEng (Hons), MSc   Page: 19 ETABS MANUAL  
  • 20. ETABS MODELING ACCORDING TO EUROCODES Table 3: Values of ψ coefficients ψο ψ1 ψ2 Category Specific Use A Domestic and residential 0.7 0.5 0.3 B Office 0.7 0.5 0.3 C Areas for Congregation 0.7 0.7 0.6 D Shopping 0.7 0.7 0.6 E Storage 1.0 0.9 0.8 F Traffic < 30 kN vehicle 0.7 0.7 0.6 G Traffic < 160 kN vehicle 0.7 0.5 0.3 H Roofs 0.7 0 0 Snow, altitude < 1000 m 0.5 0.2 0 Wind 0.5 0.2 0 Figure 10: Adding seismic mass to ETABSValentinos Neophytou BEng (Hons), MSc   Page: 20ETABS MANUAL  
  • 21. ETABS MODELING ACCORDING TO EUROCODESStep 13: Define number of modesNotes: 1. Minimum number of modes to be taken into account (EN1998-1-1,cl.4.3.3.3.1(5)): k ≥ 3.√nk is the number of modes taken into account.n is the number of storeys above the foundation or the top of a rigid basement. Valentinos Neophytou BEng (Hons), MSc   Page: 21 ETABS MANUAL  
  • 22. ETABS MODELING ACCORDING TO EUROCODESStep 14: Define restrains at the baseSelect the entire base jointsStep 15: Define diaphragms to slab Valentinos Neophytou BEng (Hons), MSc   Page: 22 ETABS MANUAL  
  • 23. ETABS MODELING ACCORDING TO EUROCODESStep 16: Checking the modelValentinos Neophytou BEng (Hons), MSc   Page: 23ETABS MANUAL  
  • 24. ETABS MODELING ACCORDING TO EUROCODES MODAL ANALYSIS RESULTSStep 1: Calculate the effective modal massDisplay> Show Tables > Modal information > Building modal information > Tablemodal participation mass ratios 1. The sum of the effective modal masses for the modes taken into account amounts to at least 90% of the total mass of the structure (EN 1998-1-1,cl.4.3.3.3.1(3)). 2. All modes with effective modal masses greater than 5% of the total mass are taken into account. Mode 1 (Translation Y - direction) Mode 2 (Translation X - direction) Valentinos Neophytou BEng (Hons), MSc   Page: 24 ETABS MANUAL  
  • 25. ETABS MODELING ACCORDING TO EUROCODES Mode 3 (Torsional)Step 2: Damage limitationsValentinos Neophytou BEng (Hons), MSc   Page: 25ETABS MANUAL  
  • 26. ETABS MODELING ACCORDING TO EUROCODESThe damage limitation requirements should be verified in terms of the interstorey drift (dr)(EN 1998-1-1,cl.4.4.3.2) using the equation below: 𝑑! 𝑎 𝑑! ∙ 𝑣 ≤ 𝑎 ∙ ℎ     => ≤ ℎ 𝑣dr: is the difference of the average lateral displacement ds in CM at the top and bottom ofstorey.v: is the reduction factor which takes into account the lower return period of the seismicaction.h: is the storey height Table 4: Damage limitation (EN1998-1-1,cl.4.4.3)For non-structural elements of brittle material attached to the structure drv≤0.005hFor building having ductile non structural elements drv≤0.0075hFor building having non-structural elements fixed in a way so as not to drv≤0.010hinterfere with structural deformation Tab;e 5: Reduction factor of limitation to interstorey drift (CYA NA EN1998-1- 1,cl.NA.2.15) Importance class Reduction factor v I 0.5 II 0.5 III 0.4 IV 0.4 1. Export results from ETABS to ECXEL Valentinos Neophytou BEng (Hons), MSc   Page: 26 ETABS MANUAL  
  • 27. ETABS MODELING ACCORDING TO EUROCODES 2. Sort the Larger value on top 3. Record the value of each storey in the spread sheet below:Valentinos Neophytou BEng (Hons), MSc   Page: 27ETABS MANUAL  
  • 28. ETABS MODELING ACCORDING TO EUROCODESDamage limitation (EN1998-1-1,cl.4.4.3) Displacement Displacement Heigh of each Reduction v*dr v*dr/h X-­‐direction                   Y-­‐direction                   Drift X Drift Y storey, h factor X - direction Y - direction dr*v<0,005-­‐0,01 dr*v<0,005-­‐0,01 dr (m) dr (m) (m) v Storey 2 0,0026 0,0026 3,00 0,50 0,00043 0,00043 OK OK Storey 1 0,0017 0,0017 3,00 0,50 0,00028 0,00028 OK OKStep 3: Second order effects 1. The criterion for taking into account the second order effect is based on the interstorey drift sensitivity coefficient θ, which is define with equation (EN 1998-1- 1,cl.4.4.2.2(2)). 𝑃!"! ∙ 𝑑! 𝜃= 𝑉!"! ∙ ℎhr: is the interstorey drift,h: is the storey height,Vtot: is the total seismic storey shearPtot: is the total gravity load at and above storey considered in the seismic design situation(G+0.3Q). Table 6: Consequences of value of P-Δ coefficient θ on the analysis θ≤0,1 No need to consider P-Δ effects P-Δ effects may be taken into account approximately by 0,1≤θ≤0,2 ! amplifying the effects of the seismic actions by !!! P-Δ effects must be accounted for by an analysis including 0,2≤θ≤0,3 second order effects explicity θ≥0,3 Not permitted 1. Explore the results from ETABS to EXCEL Valentinos Neophytou BEng (Hons), MSc   Page: 28 ETABS MANUAL  
  • 29. ETABS MODELING ACCORDING TO EUROCODES 2. Select the combo G+0,3Q and record the highest value from each storey 3. Record the heist value for VtotValentinos Neophytou BEng (Hons), MSc   Page: 29ETABS MANUAL  
  • 30. ETABS MODELING ACCORDING TO EUROCODES 4. Record all values on the spread sheet as showing belowSecond order effects (EN1998-1-1,cl.4.4.2.2) Ptot Heigh of Vtot Vtot Displaceme Displacement θ                                                              θ                                                                                       (kN) each storey, X-direction Y-direction nt Drift X Drift Y X-­‐direction                   Y-­‐direction                   h (m) (kN) (kN) dr (m) dr (m) θ≤0.1 θ≤0.1 Storey 2 709 3,00 220,00 220,00 0,00260 0,00260 OK OK Storey 1 1426 3,00 334,00 334,00 0,00170 0,00170 OK OKStep 4: Structural regularity plan Valentinos Neophytou BEng (Hons), MSc   Page: 30 ETABS MANUAL  
  • 31. ETABS MODELING ACCORDING TO EUROCODES 1. Slenderness ratio of the building λ=Lmax/Lmin<4 2. A “compact shape”: one in which the perimeter lines is always convex, or at least encloses not more than 5% re-entrant area. 3. The floor diaphragms shall be sufficient stiff in-plane not to affect the distribution of lateral loads between vertical elements. Table 7: Criteria for regularity in plan rx> 3.33eox Lateral torsional rensponse condition: rx> 3.33eoy Torsionally rigidity condition: rx> IsRegularity in plan (cl. 4.2.3.2)Check 1 - slenderness ratio cl.4.2.3.2(5)Slenderness ratio λ=Lmax/Lmin<4 = 2,80 OKRegularity in plan (cl. 4.2.3.2)Check 2 - structural eccentricity & torsional radius cl.4.2.3.2(6)Length in longitudinal direction = 56 mLength in trasverse direction = 20 mStifness in X direction Sx=1000/dxStifness in Y direction Sy=1000/dyTorsional stifness Ts=1000/RzTorsional radius ry=Ts/SxTorsional radius rx=Ts/SyRadius of gyration Is=((Lmax²+Lmin²)12)^0,5Structural eccentricity in x direction eox=Rz(Fx)/Rz(Mz)Structural eccentricity in y direction eox=Rz(Fy)/Rz(Mz)Table 1: Criteria for regularity in plan - Torsionally rigity condition Displacement Displacement Rotation Z Stifness X Stifness Y Torsional rx ry X (mm) Y (mm) (radians) (kN/m) (kN/m) Stifness (m) (m) dx dy Rz Sx Sy (kNm/radian) Ts Storey 2 7,35 7,14 8,18E-06 136054 140056 1,22E+08 29,5 30,0 Storey 1 5 6 8,18E-06 200000 166667 1,22E+08 27,1 24,7 0.3rx 0.3ry Is Is<rx Is<ry (m) (m) (m) Storey 2 8,9 9,0 17,2 OK OK Storey 1 8,1 7,4 17,2 OK OKTable 2: Criteria for regularity in plan - Lateral torsional respone condition Rotation Rz Rotation Rz Rotation Rz Eccentricity Eccentricity 3,33eox<rx 3,33eoy<ry for for for eox eoy Fx=1000kN Fy=1000kN Mx=1000kNm Storey 2 8,18E-06 8,18E-06 8,18E-06 1,00 1,00 OK OK Storey 1 8,18E-06 8,18E-06 8,18E-06 1 1,00E+00 OK OKApply forces as follow: Valentinos Neophytou BEng (Hons), MSc   Page: 31 ETABS MANUAL  
  • 32. ETABS MODELING ACCORDING TO EUROCODES Storeys Load Case Forces FX1 FX1=1000kN STOREY 1 FY1 FΥ1=1000kN MZ1 MZ1=1000kNm FX2 FX2=1000kN STOREY 2 FY2 FΥ2=1000kN MZ2 MZ2=1000kNmRepeat this process for all load case in order to obtain the displacement values. Valentinos Neophytou BEng (Hons), MSc   Page: 32 ETABS MANUAL  
  • 33. ETABS MODELING ACCORDING TO EUROCODESStep 5: Structural type of the building Table 8: Classification of structural systemWall system Vertical and lateral load: Wall resist Vb,wall>65%VbtotalFrame system Vertical and lateral load: Vb,frame>65%VbtotalFrame-equivalent dual system Vertical and lateral load: Vb,frame>50%VbtotalWall-equivalent dual system Vertical and lateral load: Vb,wall>50%VbtotalDisplay >Show Tables> Support/Sprint/Reaction 1. Explore the results from ETABS to EXCEL Valentinos Neophytou BEng (Hons), MSc   Page: 33 ETABS MANUAL  
  • 34. ETABS MODELING ACCORDING TO EUROCODESFrom load case tick the worst-case seismic design combination: COMBO 1. DL + 0.3LL + EQX + 0.3EQY COMBO 2. DL + 0.3LL + EQX – 0.3EQY COMBO 3. DL + 0.3LL - EQX + 0.3EQY COMBO 4. DL + 0.3LL - EQX – 0.3EQY COMBO 5. DL + 0.3LL + EQY + 0.3EQX COMBO 6. DL + 0.3LL + EQY – 0.3EQX COMBO 7. DL + 0.3LL - EQY + 0.3EQX COMBO 8. DL + 0.3LL - EQY – 0.3EQX 2. Select the worst-case design combo 3. Select the nodes for frames only 4. Calculate the sum of the base shear that can be resist by column in X and Y direction Valentinos Neophytou BEng (Hons), MSc   Page: 34 ETABS MANUAL  
  • 35. ETABS MODELING ACCORDING TO EUROCODESi.e VTOTAL = 1000KN VFRAMES, X ,Y = 500KN VTOTAL / VFRAME 500/1000*100= 50%Therefore the structural system of building is: Wall-equivalent dual systemHow to checking base shearBase shear can be check as follow: Table 9: Checking the base shear Direction Lower bound values Upper bound values X direction Fb = %Effective mass(X dir.)*Mass *Sdx Fb = ∑mass * Sdx Y direction Fb = %Effective mass(Y dir.)*Mass *Sdv Fb = ∑mass * SdyNote: The base shear should be within those limits NOTE: REPEAT ALL THIS PROCESS FROM BEGIN WITH THE NEW Q VALUERevised the design spectrum input data with the new q (for example if q=1.5 adopt at initialstage and the new q=3 then you have to repeat the process with the new q) Valentinos Neophytou BEng (Hons), MSc   Page: 35 ETABS MANUAL  
  • 36. ETABS MODELING ACCORDING TO EUROCODES OUTPUT DATAStep 1: Print data for steel/concrete designFile > Print Tables > Concrete Frame Design Valentinos Neophytou BEng (Hons), MSc   Page: 36 ETABS MANUAL  
  • 37. ETABS MODELING ACCORDING TO EUROCODES ADDITIONAL NOTESSHRINKAGE AREASSelect Area > Edit > Expand/Srink AreaValentinos Neophytou BEng (Hons), MSc   Page: 37ETABS MANUAL  
  • 38. ETABS MODELING ACCORDING TO EUROCODESPIN JOINTExport model to SAFEFile menu > Export > Save Story as SAFE.f2k Text FileLocal AxisLocal axis 1 X - directionLocal axis 2 Y- direction Valentinos Neophytou BEng (Hons), MSc   Page: 38 ETABS MANUAL  
  • 39. ETABS MODELING ACCORDING TO EUROCODESLocal axis 3 Z - directionLocal axis 2 (My) Y- directionLocal axis 3 (Mx) X - direction Valentinos Neophytou BEng (Hons), MSc   Page: 39 ETABS MANUAL  

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