Structural Concrete - Hassoun

References 339
One-way ribbed slab roof. The wide beams have the same total depth as the ribbed slab.
Section 9.4
The minimum shrinkage steel ratios, ρ min , in slabs are 0.002 in. for slabs in which grade 40 or grade
50 bars are used and 0.0018 in. for slabs in which deformed bars of grade 60 are used.
Maximum spacings between bars ≤5 times rib thickness ≤18 in.
Sections 9.5 and 9.6
1. Reinforcement details are shown in Fig. 9.4.
2. Distribution of loads from one-way slabs to the supporting beams is shown in Fig. 9.5.
Section 9.7
The design procedure of ribbed slabs is similar to that of rectangular and T-sections. The width of
ribs must be greater than or equal to 4 in., whereas the depth must be less than or equal to 3.5 times
the width. The minimum thickness of the top slab is 2 in. or not less than one-twelfth of the clear
span between ribs.
REFERENCES
1. Concrete Reinforcing Steel Institute (CRSI). CRSI Design Handbook, 10th ed. CRSI, Chicago, IL, 2010.
2. Portland Cement Association (PCA). Continuity in Concrete Building Frames. PCA, Chicago, IL, 1959.
3. American Concrete Institute (ACI). Building Code Requirements for Structural Concrete. ACI, ACI Code
318–14. Detroit, MI, 2014.