And unloading 66291 66291 initial precompression

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Unformatted text preview: er losses) Permissible — — b) Longitudinal prestress during winding - (3.026 7 + 0.5949) + 3.7432 = +0.121 6 c) Longitudinal prestress after losses plus beam action (-1.376 9 + 3.670 5) = +2.293 6 d) Handling before winding (-0.594 9 + 3.743 2) = +3.148 3 0.56x (@05 0.56x (25)05= –2.800 O +0.121 6 c -2.8000 0.34X &)05 0.34x (40)05 = -2.1503 +2.293 6<-2.1503 -6.6291 + 3.6705 = -2.9586 Actual - Permissible Minimum residual compressive stress +3.6705 +2.5 (0.5949+ 3.7432) = + 4.3381 0.5 x (&2)0”5 25 x = 12.5000 +4.338 1 c 12.5000 (1.3769+ 3.6705) =+5.0474 0.5x (f&)05X 40 = 20.0 +5.047 4<20.0 -0.67 (0.594 9 + 3.743 2) = + 4.3381 + 4.3381 +3.148 3 c – 0.67 e) Transport and unloading Compressive — / 0.56 x &)05 0.56 x (40)’J”5= -3.5417 -2.9586 c – 3.5417 15 +6.629 1 + 3.6705 = +10.299 6 0.5 x ~p,)o”sx 15 = 7.5 ‘ c 7.5 0.5 x &)0”5 x 40 =20 +10.299 6<20.0 !,:, ., ,! ! ~-- IS 784:2001 ANNEX E (Clause 7.4.3) THRUST AND MOMENT COEFFICIENTS E-1 The coefficients at control sections for bedding angles from 30° to 180° developed by use of Olander’s Equations are as given below: / \ Bedding Angle Location of Control Section, 0 \ >/q-OED&lp , \\ // - .- / f Moment Coeflcient, Cm Thrust Coefficients, Ct Water Ctw 0° -0.078 -0.237 +0.487 +0.079 +0.079 +0.062 104° +0.302 4.058 +0.633 +0.100 +0.125 -0.352 +0.376 +0.194 +0.100 +0.194 +0.085 180° 0° 30° Pipe Ctp . Earth C,e –0.071 -0.230 +0.425 +0.076 +0.076 +0.065 Pipe C,p Water C*W Earth c,, +0.173 -0.059 +0.576 +0.096 +0.096 +0.086 -0.310 +0.345 +0.155 +0.155 +0.145 –0.061 -0.220 +().382 +0.070 +0.070 +0.069 104° +0.295 –0.062 +0.539 +0.088 +0.088 +0.089 180° +0.207 -0.270 +0.326 +0.121 +0.121 +0.125 0° -0.046 -0.205 +0.35 1 +0.063 +0.063 +0.073 100° 180° +0.282 +0.245 –0.065 –0.233 +0.516 +0.316 +0.077 +0.091 +0.077 +0.091 +0.09 1 +0.109 0° 120° +0.302 +0.168 0° 90° 104° 180° 60° –0.026 –0.185 +0.331 +0.054 +0.054 +0.079 +0.267 -0.067 +0.063 +0.063 +0.094 +0.282 –0.196 +0.313 +0.065 +0.065 +0.097 0° –0.000 -0.159 +0.318 +0.044 +0.044 +0.087 90° +0.250 -0.068 +0.500 +0.047 +0.047 +0.095 180° 180° 96° 180° 150° +0.504 +0.318 –0.159 +0.318 +0.044 +0.044 +0.087 16 — - .—-.. .——. ---- IS 784:2001 ANNEX F (Clauses 7.5, G-3 and J-4.2.2. 1) LOSS OF PRESTRESS F-1 Explanation of various symbols used in subse- where quent clause is given in Annex K. ~,,”n~ = Initial stress in core in longitudinal direction in N/mm2. F-2 CALCULATION FOR LOSS OF PRESTRESS sl No. 1. 2. 3. 4. 5. ~, = Initial stress in core in circumferential direction in N/mm*. Lih3ng = E, Longitudinal Circum(Pre Tensioning) ferential (Post Tensioning) — 3.2&i Elastic deformation 0.16Ji Relaxation of wire 0.16& i10.~ 2.5~i due to Deformation 2“5fsi long creep 0.0001 E, 0.0001 E, Deformation due to shrinkage Yield due to mould shortening (wire stretch 2 E, due to filling vibrations L+80 during spinning, etc, slippage = 2 mm) = Modulus of elastici...
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