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Steps for Seismic Analysis 1. Select SI units [kNm] 2. Define the grid and story data 3. Define materials (E cd cracked = 0.5*E cd ) Reinforced Concrete, with dense aggregate ... 2400 kg/m3 Plain Concrete, with natural stone aggregate ... 2300 kg/m3 Mass per unit volume = 2.4 Weight per unit volume = 2.4* 9.80665 = 23.54 Eurocode 2 : E cm = 22 x (f cm /10) 0,3 , f cm in MPa f cm = f ck + 8 , f ck in MPa C12/15: fck = 12 MPa (cylinder, 15 on cube) fcm = 12 + 8 = 20 MPa E cm = 22 x (20/10) 0,3 = 27.09 MPa => E cm = 27 MPa (Table 3.1 SR EN 1992-1-1:2004) E cd cracked = 0.5*E cd = 13.5 MPa = 13.5 N/mm 2 = 13.500.000 N/m 2 4. Define the cross-section for columns and beams 5. 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 + Ai Af = bf x hf Ai = (hgr - hf) x bgr bf = 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 beams 13. 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 -> Rigid 15-17. Mesh and pier for walls 18. Define static load cases - gravity loads
