steps for seismic analysis
TRANSCRIPT
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Steps for Seismic Analysis
1. Select SI units [kNm]2. Define the grid and story data3. Define materials (Ecd
cracked = 0.5*Ecd)Reinforced Concrete, with dense aggregate ... 2400 kg/m3Plain Concrete, with natural stone aggregate ... 2300 kg/m3Mass per unit volume = 2.4Weight per unit volume = 2.4* 9.80665 = 23.54Eurocode 2 :Ecm = 22 x (fcm/10)0,3 , fcm in MPafcm = fck + 8 , fck in MPaC12/15:fck = 12 MPa (cylinder, 15 on cube)fcm = 12 + 8 = 20 MPaEcm = 22 x (20/10)0,3 = 27.09 MPa => Ecm = 27 MPa (Table 3.1 SR EN 1992-1-1:2004)Ecd
cracked = 0.5*Ecd = 13.5 MPa = 13.5 N/mm2 = 13.500.000 N/m2
4. Define the cross-section for columns and beams5. Define (Draw) the columns 6. Define (Draw) the beams
ETABS: (Menu) Assign -> Frame/Line -> Frame Property Modifiers -> Mass = Weight = n
n = (A-Af)/A (~ 0.5)A = Af + AiAf = bf x hfAi = (hgr - hf) x bgrbf = 0.15*(L1 + L2) < Lmin/2 (1 m)
7. Define the sections for slabs (membrane)8. Define (Draw) the slabs 9-12. Define and Draw walls and coupling beams13. Assign the End (Lenght) Offsets for columns & beams
ETABS: Select -> by Frame Section (all columns & beams)Assign -> End (Lenght) Offsets... -> Automatic & Rigid-zone factor = 1
14. Assign Joint/Point Rigid Diaphragm (for slabs joints)ETABS: Select -> by Wall/Slab/Deck Section (all Slabs)
Assign -> Shell/Area -> Diaphragms -> New -> Rigid15-17. Mesh and pier for walls18. Define static load cases - gravity loads
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19. Assign gravity uniform loads to slabs - current floor
20. Assign uniform loads to perimetrical beams - curtain walls21. Replicate story22. Assign gravity uniform loads to slabs - terrace
ETABS: Assign -> Shell/Area Loads -> Uniform
23. Assign uniform loads to perimetrical beams - attic
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24. Define Mass Source
25. Check model & Set Analysis OptionsETABS: Analyze -> Check Model -> check all buttons
Analyze -> Set Analysis Options -> Set Dynamic Parameters -> Modes (6)26. Run Analysis27. Show Mode Shapes & Display “Modal Participating Mass Ratio”
ETABS: Display -> Show Tables -> Modal Inf/Building Modal Inf/Mass Ratios-> Building Output/Center Mass Rigidity
28. Define static load cases - eartquake loads
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29. Run Analysis30. Verify the GF story shear (comparing with hand-calculated conventional seismic force Fb = c*Wt)31-32. Shear walls33. Show Deformed Shape for EQ load cases34. Visualize the joint displacement and Lateral Drifts
![Page 5: Steps for Seismic Analysis](https://reader035.vdocuments.us/reader035/viewer/2022081412/54489214afaf9f35088b4ad1/html5/thumbnails/5.jpg)
35. Check the amplified drifts fost SLS and SLU
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36. Define LOAD COMBINATIONS
37. Show wall forces38. Show beam forces39. Show column forces for EQ on X and Y dir40. Print Diagrams41. Modify colors for print