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composite beam problems.pdf
The document discusses composite beam design and calculations in structural engineering, presenting solutions for various problems related to moment capacity and beam selection. Key factors include the analysis of a lightweight concrete slab supported by steel beams, examining service loads, shear connectors, and deflection checks. It also cites references for further reading in structural steel design.
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composite beam problems.pdf
- 1. COMPOSITE CONSTRUCTION: COMPOSITE BEAMSOLVED PROBLEMS 1 Presented By Eng. ZEINAB AWADA Email Zeinabawada198@gmail.com MASTER OF CIVIL ENGINEERING-LEBANON ADVANCED STRUCTURAL SYSTEMS COURSE
- 2. Problem1(calculation of momentcapacity) K E= modulus of elasticity of steel 29000 Ksi If Case 2: a > t slab then Distance from PNA to top of flange
- 3. Solution (compact ornon) H web (Compact web) (plastic distribution)
- 4. Solution (position PNA) Case1: a < t slab so PNA in slab Case 2: a > t slab so PNA in steel beam If C>T PNA in steel flange If C<T PNA in steel beam web
- 5. Solution Distance from PNAto top of flange
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- 7. • Beams 10ft on center with 36 ft simple spans are to be selected to support a 4-in deep lightweight concrete slab on a 3-in-deep formed steel deck with no shoring. • The ribs for the steel deck, which are perpendicular to the beam center lines have average widths of 6 in. • The service dead load(including the beam weight) is 0,78 k/ft of length of the beams and the service live load is 1.2 k/ft. Fy=50Ksi, f’c=3Ksi Problem 2 (beam design)
- 8. Solution 1. beam selection(y1,y2,Mu) If a <t slab (Case 1) Assume Y1:Distance from PNA to top of flange = 0 Y2: distance from centroid of effective concrete area to top of flange Y2: Yconcrete - a/2
- 9. • Y1:Distance fromPNA to top of flange = 0 • Y2: distance from centroid of effective concrete area to top of flange = 6in • Mu=463.3 k.ft LRFD • Ma = 320 k.ft ASD • Try Shape: W16*31 • Mn = 478 k.ft Solution 1. beam selection
- 10. • Y1:Distance fromPNA to top of flange = 0 • Y2: distance from centroid of effective concrete area to top of flange = 6in • Mu=463.3 k.ft LRFD • Ma = 320 k.ft ASD • Try Shape: W16*31 • Mn = 478 k.ft Solution 1. beam selection
- 11. Solution (W sectioncharacteristics)
- 12. Solution (W sectioncharacteristics)
- 13. Solution 2.Check Mu <øMn Ʃ𝑄n = As.Fy Or Table a < t slab then Y1= 0
- 14. Solution 3.Design of shearconnectors Given: • Light weight concrete • Fc’ = 3ksi • Ribs of steel deck are perpendicular to the beam center • Stud diameter = ¾ in2
- 15. Solution 4. Check strengthof W section before concrete hardens: øMn>Mu = γ * t * tributary length Beams 10 ft on center with 36 ft simple spans. The ribs average widths of 6 in. DEAD LOADS: 1. Deck weight (2psf) 2. Beam weight(31lb/ft) LIVE LOADS 1. Slab weight 2. Rib weight 3. Construction live load(20psf) W16*31
- 16. Solution 5.Check for serviceload deflection before concrete hardens (Service load)
- 17. Solution 5.Check for serviceLL deflection after composite section is available ∆L= ML.L2/C1*ILB Given (Service live load) = 1.2k/ft
- 18. Solution 6.Check shear DL =0,78 k/ft LL = 1.2 k/ft
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- 24. THANK YOU 24 THANK YOU Hopeyou enjoyed my presentation ! Contact me for any help zeinabawada198@gmail.com
- 25. ✓ Structural steeldesign,5th edition, jack C.Mc Cromac,S tephan F. Csernak ✓ American institude of steel construction, Steel construction manual, 14th edition ✓ Chapter 9 ❖ References 25