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Design of Concrete Structure II University of Palestine
بسم الله الرحمن الرحيم Example # 2 Instructor: Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
بسم الله الرحمن الرحيم Example # 2 3m 5m 4m C16 C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 Design the two way solid slab shown in Figure. The covering materials weigh 2.3 KN/m2 and the live load is 3.2 KN/m2. Also, Calculate the factored load acting on beam 1 due to slab. Use fc’ = 25 MPa, fy = 420 MPa. All beams are 250mm wide Beam 1 Instructor: Page 0 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
بسم الله الرحمن الرحيم Solution 1- Evaluate slab thickness: Ln,max = 5.0 – 0.25 = 4.75 m = 4750 mm The largest slab thickness is given by Use a slab thickness of 140 mm =14 cm 2- Determine the total factored load per unit area of slab: wu = 1.2[0.14(25)+2.3] + 1.6(3.2) = 12.1 KN/m2 wu = 12.1 KN/m2 =1.21 t/m2 Instructor: Page 1 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
3- Evaluate load distribution in both directions: Based on Egyptian code load coefficients: 3m 5m 4m C16 C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 S1 S5 S4 S3 S6 S7 S8 S2 For panel S1,S2 and S8: For panel S3 and S6: For panel S4: Instructor: Page 2 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
3- Evaluate load distribution in both directions: 3m 5m 4m C16 C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 S1 S5 S4 S3 S6 S7 S8 S2 For panel S5: For panel S7: For all panels, For a strip 1m wide, ws = α wu wl = β wu Instructor: Page 3 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
Loads in both directions: C1 C2 C3 C4 3m 5m 4m 5.75 KN/m2 2.78 KN/m2 5.75 KN/m2 2.78 KN/m2 C5 C8 C6 C7 2.30 KN/m2 6.25 KN/m2 5.75 KN/m2 2.78 KN/m2 6.84 KN/m2 2.10 KN/m2 C9 C12 C10 C11 2.30 KN/m2 6.25 KN/m2 4.79 KN/m2 3.57 KN/m2 5.75 KN/m2 2.78 KN/m2 C13 C14 C15 C16 Instructor: Page 4 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
4- Select Representative 1m wide design strips to span in short and long direction. C1 C2 C3 C4 3m 5m 4m Strip #1 Strip #6 C5 C8 C6 C7 Strip #2 Strip #5 Strip #4 C9 C12 C10 C11 Strip #3 C13 C14 C15 C16 Instructor: Page 5 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
2.78 KN/m 5- Design each strip For Example, take Strip # 1 Average effective depth (davg) davg = = 108 mm Assuming that dstirrup = Φ 8 && dbar = Φ12 A - Check slab thickness for shear 5 m 5 m 8.7 KN 5.2 KN S.F.D 8.7 KN 5.2 KN 8.7 KN.m B.M.D 4.9 KN.m 4.9 KN.m Instructor: Page 6 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
2.78 KN/m Design of Strip # 1(Contd.) B- Design of reinforcement 5 m 5 m 8.7 KN 5.2 KN 8.7 KN 5.2 KN 8.7 KN.m 4.9 KN.m 4.9 KN.m Φ 300 mm Φ 300 mm Φ 300 mm Instructor: Page 7 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
Check slab thickness for beam shear for each strips and determine the required amount of reinforcement for each strips then prepare neat design drawings showing slab thickness and providing reinforcement. 3m 5m 4m C16 C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 Φ 300 140mm Sec. A-A Instructor: Page 8 Eng. Mazen Alshorafa

Design of Concrete Structure II University of Palestine
3m 5m 4m C16 C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 Φ 300 Φ 300 Φ 300 Φ 300 140mm Φ 300 Φ 300 Φ 300 Sec. A-A Φ 300 Φ 300 Φ 300 Φ 300 Φ 300 Φ 300 Instructor: Page 9 Eng. Mazen Alshorafa