Supenm Li Tlm For the prestressed stinger 8m shoun determine

Supenm Li Tlm For the prestressed stinger 8m shoun, determine the tol X, 125 mm N,=ws --X22b0mm These are pretal re beans manufactured at the Determine the maximunm P Such that the tension stess a 120mm Superimposed n 8.lka at pind Bis sero at the 48a tanster stoa Li ermine-the-mannum Pt bosed on the allanable 12 SM h 0mmompession Shess baaster R-0.18 Class T the maximunl Superimposed flooc oad in thot the be om Can Cany based On the allbuale compressive stess-ei service strge S. Solve as Pb. but hased on allevable tenson service stage

Solution

Given , Eff span = 7.1+7.1 = 14.2m

D.L = 8.1 Kpa

L.L = 4.8 Kpa

f’ci = 42 Mpa

f’c = 55Mpa

h=90mm

Solution :

H= y₁+y₂+y₁+y₂ = 180+420+180+420 = 1200 mm

A= bh = 770 x 1200

   = 92x10⁴ mm⁴

I = bh³ = 770 x 1200³

      12           12

   = 110.8x10⁹ mm⁴

2. Tensile stress at B

e = h/6 = 200 mm

Z =   I = 110.8x10 ⁹ = 184x10⁴

   y         385

fc = P + Pe + M

        A     Z      I

55=    P             +   Px200       + (8.1+ 4.8)

         92x10⁴     184x10⁶    110.8x10⁹

     P= 25.46x10⁶

3. Compression stess

f\'ci = 42Mpa

42 = P             +   Px200       + (8.1+ 4.8)

         92x10⁴      184x10⁶      110.8x10⁹

P = 19.44 x 10⁶