Page 1

Beam Span = 20 m² Breadth = Compression Positive24.286 kN/m³ 350 Prestress/Area Prestress•Ecc/Z BM/Z Total Stress

Beam Section = 0.35 m² Top 13.70 MPa -20.22 6.52 0.00 MPaBeam Wt.= 8.50 kN/m

BM = -425.0 kN-m(Sagging Negative)

-460 = Ytop0.03 m⁴

Ztop = -0.0652 m³

Depth = 810

Zbot = 0.0857 m³P₀ = 75% UTS = 4795 kN 275 = ecc

At TransferPrestress lost = 0%

4795 kN Bottom 13.70 MPa 15.38 -4.96 24.13 MPa

γconc =

2nd Mom, I =

Centroid Concrete

Centroid Prestress

Pt = (1- α)•P₀ =

Page 2

Effective slab width = beam spacing of 1200 mm c/c

150 Slab weighs 4.37 kN/m/beam13.70 -20.22 9.87 3.35

Slab wt. adds BM -218.6 kN-mtotal self wt. BM -643.6 kN-m

Assume prestress unchangedsince transfer

13.70 15.38 -7.51 21.58

When Slab Is Cast

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Elastic Moduli Compression Positive30 GPa Self Wt.BM/Z Total36 GPa & Prestress Stress

Effective slab width = 1200 c/c Transformed slab width = 1000 13.43 13.43Transformed

0.00028 m⁴ 150 area = 0.150 m²0.0155 m⁴ 8.53 8.53

Composite I = 0.05447 m⁴ 3.35 10.23 13.6336

-0.1325 m³-0.2087 m³0.0992 m³

144

In Service 810Precast Area

0.35 m²

Self wt.BM = -643.6 kN-m 405Imposed load = 35.6 kPaImposed BM = -2136.0 kN-m

Sagging Negative21.58 -21.53 0.0 MPa

Total Prestress loss = 0% 350

Eslab = Imposed BM/ZEbeam =

CentroidSlab

Centroidal Islab =Centroidal Ibeam =

Ztslab =Ztbeam = Centroid

All ConcreteZbcomp =

Centroid Precast