Design of Concrete Structure I

1. Dr. Ali Tayeh First Semester 2009 Design of Concrete Structure I

2. Lecture 3 Loads ACI 318-05

3. Dead Load (Slab & Beam) Concrete structural system

4. Dead Load (Slab & Beam) Slab types Solid slab • One-way slab • Two way slab Ribbed Slab • one way or two way according to rib system The effect of slab type Oneway slab Two-way slab

5. Solid slab Two way slab One-way slab Ribbed Slab Two way slab One-way slab

6. Dead Load (Slab & Beam)

8. Different type of Ribbed slab according to their position

10. Dead Load (Slab own weight ) assume depth 30 cm(22cm block +8cm concrete) Geometry of rib in one way ribbed slab

11. Dead Load (Slab own weight ) assume depth 30 cm(22cm block +8cm concrete) • Own weight of slab • From geometry of rib as shown • - Total volume of rib (hatched) = 0.55 x 0.3 x 0.25 = 0.04125 m3 • - Volume of hollow block = 0.4x0.25x0.22= 0.022 m3 • - Concrete density = 25 KN/m3. • - Net concrete volume = 0.04125 – 0.022 = 0.01925 m3 • - Weight of concrete = 0.01925 x 25 = 0.48125 KN • - Weight of concrete /m2 = • - Weight of hollow block /m2 = • - Total Own weight=3.5+1.6=5.1 KN/m2

12. Dead Load (Covering Material) • Covering materials • - Plaster coat density = 21 KN / m3, thickness = 0.02 m • - Weight of plaster / m2 = 21x 0.02 = 0.42 KN/m2 • - Sand density = 18 KN / m3, thickness = 0.08 m • - Weight of sand / m2 = 18 x 0.08 = 1.44 KN/m2 • - Mortar density = 21 KN / m3, thickness = 0.025 m • - Weight of mortar / m2 = 21 x 0.025 = 0.525 KN/m2 • - Tiling density = 22 KN / m3, thickness = 0.025 m • - Weight of tiling / m2 = 22 x 0.025 = 0.55 KN/m2 • Total Weight of covering materials • =0.42+1.44+0.525+0.55=2.94 KN/m2

13. Dead Load (Walls) • Partition load = 2.5 KN/m2 • Total weight/ m2 • = Total Own weight + Total Weight of covering materials • = 5.1+2.94+2.5= 10.6 KN/m2 • Service live load = 4 KN/m2 According to (ASCE7-05 Table 4-1)

14. 3 m 1 m

15. Live Load

16. Astructural Design code Astructural Design codeis a code that involves the design of a certain type of structures (reinforced concrete, structural steel, etc.). The structural code that will be used extensively throughout this course is The American concrete Institute (ACI-318-05) , which is one of the most solid codes due to its continuing modification, improvement, and revision to incorporate the latest advancements in the field of reinforced concrete design and construction.

17. Design Methods The Ultimate – Strength Design Method • At the present time, the ultimate-strength design method is the method adopted by most prestigious design codes • In this method, members are designed such that the internal forces in the members produced by factored loads do not exceed the corresponding strength capacities and allowing for some capacity reduction.

18. The Working-Stress Design Method • Before the introduction of the strength-design method in the ACI building code in 1956, the working stress design method was used in design. • This method is based on the condition that the stresses caused by service loads without load factors are not to exceed the allowable stresses which are taken as a fraction of the ultimate stresses of the materials, for concrete and for steel

19. Load Factors In this course, we will us this load factorU =1.2 D + 1.6 L

20. Strength reduction Factor