Reinforced Concrete II Hashemite University The Hashem ite University Departm ent of Civil Engineering Lecture 2 Lecture 2 – – One One- -way Joist way Joist Slab System Slab System Dr. Hazim Dwairi Dr Hazim Dwairi Dr Hazim Dwairi Dr. Hazim Dwairi Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II One One- -way Joist Floor System way Joist Floor System Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Dr. Hazim Dwairi 1
Reinforced Concrete II Hashemite University One One- -way Joist Floor System way Joist Floor System Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II One One- -way Joist way Joist Floor System Floor System G Genera l fra m ing Genera l fra m ing G l f l f i i la y out of the p a n joist la y out of the p a n joist sy stem sy stem Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Dr. Hazim Dwairi 2
Reinforced Concrete II Hashemite University General fram ing layout of the pan General fram ing layout of the pan joist system joist system Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II ACI Code Recom m endations ACI Code Recom m endations • ACI 8.13.1: Joist construction consists of a ACI 8.13.1: Joist construction consists of a monolithic combination of regularly spaced monolithic combination of regularly spaced monolithic combination of regularly spaced monolithic combination of regularly spaced ribs and a top slab arranged to span in one ribs and a top slab arranged to span in one direction or two orthogonal directions. direction or two orthogonal directions. Solid Slab, h s = larger of 50mm without filler 40mm with filler (1/12) S S h s Max. = (3.5)b Slope 1:12 Max. 750mm Min. b=100mm Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Dr. Hazim Dwairi 3
Reinforced Concrete II Hashemite University Minim um Slab System Depth Minim um Slab System Depth • Based on deflection control. use table 9.5(a) in Based on deflection control. use table 9.5(a) in the ACI code to check minimum thickness the ACI code to check minimum thickness the ACI code to check minimum thickness the ACI code to check minimum thickness required. required. Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Distribution Rib (Cross Rib) Distribution Rib (Cross Rib) Distribution Ribs Distribution Ribs • Placed perpendicular to joists* Placed perpendicular to joists* p p p p j j • Spans < 6.0 m: Use None Spans < 6.0 m: Use None • Spans 6.0 Spans 6.0- -9.0 m: Provided at 9.0 m: Provided at midspan midspan • Spans > 9.0 m: Provided at third Spans > 9.0 m: Provided at third- - points points At least one continuous φ 12 bar is φ 12 b • At least one continuous At l At l t t ti ti 12 bar is 12 b i i provided at top and bottom of provided at top and bottom of distribution rib. distribution rib. *Note: not required by ACI Code, but *Note: not required by ACI Code, but typically used in construction typically used in construction Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Dr. Hazim Dwairi 4
Reinforced Concrete II Hashemite University Dead Load Calculations Dead Load Calculations • Permanent loads such as fixed Permanent loads such as fixed machines or furniture machines or furniture • Weight of the structural elements Weight of the structural elements (R.C. unit weight = 25 (R.C. unit weight = 25 kN kN/m /m 3 ) • Weight of fixed attachments such as Weight of fixed attachments such as g tiles, mortar, false ceiling …etc. tiles, mortar, false ceiling …etc. Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Typical One Typical One- -way Joist Slab way Joist Slab Typical Cross-Section Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Dr. Hazim Dwairi 5
Reinforced Concrete II Hashemite University Load Calculations Load Calculations • Slab Loads: Slab Loads: – Tiles Tiles = (0.025) (22) = (0.025) (22) = 0.55 = 0.55 kN kN/m /m 2 2 – Mortar Mortar = (0.025) (22) = (0.025) (22) = 0.55 = 0.55 kN kN/m /m 2 2 – Sand Fill Sand Fill = (0.100) (13) = (0.100) (13) = 1.30 kN = 1.30 kN/m /m 2 2 – Solid Slab Solid Slab = (0.070) (25) = (0.070) (25) = 1.75 = 1.75 kN kN/m /m 2 2 /m 2 Total Total = 4.15 = 4.15 kN kN/m • Rib Loads: Rib Loads: – Joist Web Joist Web = (0.18) (0.135) (25)= 0.61 = (0.18) (0.135) (25) = 0.61 kN kN/m /m – 5 Blocks/m 5 Blocks/m = 5 (0.18 = 5 (0.18 kN kN/Block) /Block) = 0.90 = 0.90 kN kN/m /m – Plaster Plaster = (0.52) (0.025)(22) = 0.29 kN = (0.52) (0.025)(22) = 0.29 kN/m /m Total Total = 1.80 = 1.80 kN kN/m /m Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Load Calculations Load Calculations • Total Ultimate Rib Load Total Ultimate Rib Load – Dead Load from Slab Dead Load from Slab= (0.52) (4.15) = 2.16 Dead Load from Slab Dead Load from Slab = (0.52) (4.15) = 2.16 kN (0 52) (4 15) (0 52) (4 15) 2 16 2 16 kN kN/m kN/m /m /m – Live Load from Slab Live Load from Slab = (0.52) (2.0) = (0.52) (2.0) = 1.04 = 1.04 kN kN/m /m w u = 1.2 (1.80 + 2.16) + 1.6 (1.04) = = 1.2 (1.80 + 2.16) + 1.6 (1.04) = 6.42 6.42 kN kN/m /m • Total Ultimate Load on Slab: Total Ultimate Load on Slab: w u = 6.42/0.52 = = 6.42/0.52 = 12.34 /m 2 2 12.34 kN kN/m Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Dr. Hazim Dwairi 6
Reinforced Concrete II Hashemite University Ca ses of Loa d ing (Pa ttern Loa d s) Ca ses of Loa d ing (Pa ttern Loa d s) • Using influence lines to determine pattern loads Using influence lines to determine pattern loads • Largest moments in a continuous beam or frame Largest moments in a continuous beam or frame occur when some spans are loaded and others occur when some spans are loaded and others are not. are not. • Influence lines are used to determine which Influence lines are used to determine which spans to load and which spans not to load. spans to load and which spans not to load. Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Qua lita tiv e Influence Lines Qua lita tiv e Influence Lines The The Mueller Breslau principle can be stated as principle can be stated as Mueller- -Breslau follows: follows: follows: follows: If a function at a point on a structure, such as If a function at a point on a structure, such as reaction, or shear, or moment is allowed to act reaction, or shear, or moment is allowed to act without restraint, the deflected shape of the without restraint, the deflected shape of the structure, to some scale, represents the structure, to some scale, represents the influence line of the function. influence line of the function influence line of the function influence line of the function. Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Dr. Hazim Dwairi 7
Reinforced Concrete II Hashemite University Qua lita tiv e Influence Lines Qua lita tiv e Influence Lines Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II One One- -way Joist Slab way Joist Slab Design Exam ple Design Exam ple • Design a typical Design a typical joist and solid slab joist and solid slab joist and solid slab joist and solid slab for the floor for the floor system shown system shown below. below. • Floor system is Floor system is part of residential part of residential part of residential part of residential building. building. Dr. Hazim Dwairi Dr. Hazim Dwairi The Hashemite University The Hashemite University Reinforced Concrete II Reinforced Concrete II Dr. Hazim Dwairi 8
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