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PRECAST CONCRETE HOLLOWCORE SLAB DESIGN (EN1992)
In accordance with EN1992-1-1:2004 + A1:2014 incorporating corrigenda January 2008, November 2010 and January
2014 and the UK national annex
Summary table
Description                                  Unit    Capacity       Applied          Utilisation       Result
Bending moment                               kNm     75.3           20.1             0.267             Pass
Shear force                                  kN      82.3           23.0             0.279             Pass
Spalling stress                              N/mm2 1.436            0.646            0.450             Pass
Compressive stress                           N/mm2 12.735           10.290           0.808             Pass
Initial camber                               mm      17.5           2.6              0.147             Pass
Camber after installation                    mm      11.7           4.0              0.340             Pass
Long term deflection                         mm      7.0            -1.7             0.247             Pass
Slab geometry
Nominal width of slab                         bnom = 1000 mm
Width of slab                                 b = 1000 mm
Width of top flange                           btf = 1000 mm
Depth of slab                                 h = 150 mm
Thickness of top flange                       htf = 28 mm
Thickness of bottom flange                    hbf = 28 mm
Width of inner ribs                           bw,i = 34.5 mm
Width of end ribs                             bw,e = 38 mm
Total width of ribs                           bw,t = (N - 1)  bw,i + 2  bw,e = 352 mm
Number of cores                               N=9
Width of cores                                bc = 72 mm
Height of cores                               hc = h - htf - hbf = 94 mm
Total width of cores                          bc,t = N  bc = 648 mm
                                                     1000
                          28
150
       38     72   34.5
                          94
                          28
                                                     1000
Geometric properties
Cross-sectional area                          Ac = 146610 mm2
Height of neutral axis                        hna = 98 mm
First moment of area                          Sc = 6575578 mm3
Moment of Inertia                             Ic = 672726664 mm4
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Slab details
Effective span                                      Le = 3500 mm
Bearing length                                      lb = 100 mm
Loading details
Live load                                           Flive = 4 kN/m2
Partitions                                          Fpart = 1 kN/m2
Finishes                                            Ffin = 0.5 kN/m2
Density of concrete                                 yconc = 25 kN/m3
Self weight                                         Fswt = Ac  yconc / bnom = 3.665 kN/m2
Partial load factors
Permanent loads                                     yG = 1.35
Variable loads                                      yQ = 1.5
Quasi-permanent variable load factor                ψ2 = 0.3
Concrete details
Concrete class                                      C50/60
Cement strength class                               N
Aggregate type                                      Quartzite
Maximum aggregate size                              hagg = 20 mm
Partial factor for concrete - Table 2.1             yC =
1.5 Concrete properties at 28 days - Table 3.1
Characteristic compressive cylinder strength fck = 50 N/mm2
Compressive strength coefficient for flexure and axial loading - cl.3.1.6(1)
                                                    αcc = 0.85
Design compressive strength for flexure and axial loading - exp.3.15                      fcd = αcc  fck / yC = 28.333
N/mm2 Comp.strength coefficient for shear - cl.3.1.6(1)                                   αccv = 1
Design compressive strength for shear - exp.3.15 fcdv = αccv  fck / yC = 33.333
N/mm2 Mean value of concrete cylinder comp.strength              fcm = fck + 8
N/mm2 = 58 N/mm2
Mean value of axial tensile strength                fctm = 0.3 N/mm2  (fck / 1 N/mm2)2/3 = 4.072
N/mm2 Secant modulus of elasticity                   Ecm = 22 kN/mm2  (fcm / 10 N/mm2)0.3 = 37278
N/mm2 Characteristic axial tensile strength - 5% Fractile fctk,0.05 = 0.7  fctm = 2.85 N/mm2
Tensile strength coefficient - cl.3.1.6(2)          αct = 1
Design tensile strength - exp.3.16                  fctd = αct  fctk,0.05 / yC = 1.9 N/mm2
Ultimate compressive strain                         scu3 = (2.6 + 35  ((90 - fck / 1 N/mm2) / 100)4) / 1000 =
0.003496 Concrete properties at release
Time of release                                     2 days
Cement type coefficient - cl.3.1.2(6)               s = 0.25
Time dependent comp.strength coefficient - exp.3.2                                        βcc,t = exp(s  (1 - (28 / t)0.5)) = 0.504
Mean value of comp.strength - exp.3.1               fcm,t = βcc,t  fcm = 29.225 N/mm2
                                                    α=1
Mean value of axial tensile strength - exp.3.4 fctm,t = βcc,tα  fctm = 2.052 N/mm2
Characteristic axial tensile strength - 5% Fractile fctk,0.05,t = 0.7  fctm,t = 1.436
N/mm2 Char.compressive cylinder strength - cl.3.1.2(5)            fck,t = fcm,t - 8 N/mm2
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= 21.225 N/mm2
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Secant modulus of elasticity - exp.3.5            Ecm,t = (fcm,t / fcm)0.3  Ecm = 30349 N/mm2
Prestressing strand details
Strand type                                       BS 5896 standard strands
Strand class                                      2
Modulus of elasticity                             Ep = 195 kN/mm2
Bond condition                                    Good
Strand selected                                   10 x 9.3ф strands
Area per strand                                   Ap,s1 = 52 mm2
Nominal tensile strength                          fpk,s1 = 1770 N/mm2
Characteristic 0.1% proof load                    Fp0.1,s1 = 78 kN
Cover from soffit;                                cs1 = 30 mm
Total area of prestressing strands                Ap = 10  Ap,s1 = 520 mm2
Height to steel centroid                          hcp = cs1 + фs1 / 2 = 34.7 mm
Eccentricity of prestressing strands              zcp = hna - hcp = 63.4 mm
Characteristic tensile strength                   fpk = fpk,s1 = 1770 N/mm2
Characteristic 0.1% proof-stress                  fp0.1k = (10  Fp0.1,s1) / Ap = 1500 N/mm2
Maximum stress factors - cl. 5.10.2.1(1)          k1 = 0.8
                                                  k2 = 0.9
Max.stress applied to the tendon - cl.5.10.2.1(1) σp,max = min(k1  fpk, k2  fp0.1k) = 1350
N/mm2 Force applied to tendons - exp.5.41         Pmax = Ap  σp,max = 702 kN
Limiting prestressing force - cl.3.3.2(5)         Plim = 0.7  fpk  Ap = 644.3 kN
Absolute value of initial prestress               σpi = min(Pmax, Plim) / Ap = 1239
N/mm2
Final prestressing force after losses
Initial losses
a. Short term relaxation loss (48 hours)
Time (hours)                                 t = 48
Relaxation percentage loss at 1000 hours after prestressing - cl.3.3.2(6)
                                                  p1000 = 2.5
Stress ratio                                      µ = σpi / fpk = 0.7
Absolute value of the relaxation losses of the prestress - exp.3.29
                                               σpr = σpi  0.66  p1000  exp(9.1  µ)  (t / 1000)0.75  (1 - µ)  10-5 = 6.03 N/mm2
Prestress just before release                     σpr = σpi - σpr = 1233 N/mm2
b. Elastic deformation loss due to prestress
Force in tendons                                  P = σpr  Ap = 641.1 kN
Stress in concrete at tendons                     fc = P / Ac + P  zcp2 / Ic = 8.2
N/mm2 Elastic deformation loss due to prestress Pel = (Ep / Ecm,t)  fc = 52.7
N/mm2 Total of initial losses
                                                  σpr,el = σpr + Pel = 58.7 N/mm2
Prestress after initial losses                    σpm0 = σpi - σpr - Pel = 1180.3 N/mm2
Tendon stress factors - cl.5.10.3(2)              k7 = 0.75
                                                  k8 = 0.85
Maximum value of prestress after initial losses - cl.5.10.3(2)
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                                                        σpm0,max = min(k7  fpk, k8  fp0.1k) = 1275
N/mm2 Prestressing force at release - exp.5.43                Pm0 = min(σpm0, σpm0,max)  Ap = 613.8
kN
Time dependent losses
Stress in concrete adjacent to tendons at 48 hours σc,QP = Pm0 / Ac + Pm0  zcp2 / Ic = 7.848 N/mm2
a. Loss due to creep
Perimeter in contact with atmosphere - Annex B.1(1)
                                                        u = 2  b = 2000 mm
Notional size of member - exp.B.6                       h0 = 2  Ac / u = 146.6 mm
Concrete strength coefficients - exp.B.8c               α1 = (35 N/mm2 / fcm)0.7 =
0.702
                                                        α2 = (35 N/mm2 / fcm)0.2 = 0.904
                                                        α3 = (35 N/mm2 / fcm)0.5 = 0.777
Relative humidity at release                            RH = 70
Relative humidity factor - exp.B.3b                     ф70 = (1 + (1 - RH / 100) / (0.1  (h0 / 1 mm)1/3)  α1)  α2 = 1.265
Relative humidity and size coefficient - exp.B.8b
                                                βH,release = min(1.5  (1 + (0.012  RH)18)  h0 / 1 mm + 250 αα 3, 1500  α3) =
                                                423.7
Ambient relative humidity                               RH = 50
Relative humidity factor - exp.B.3b                     ф50 = (1 + (1 - RH / 100) / (0.1  (h0 / 1 mm)1/3)  α1)  α2 = 1.506
Relative humidity and size coefficient - exp.B.8b
                                                  βH,final = min(1.5  (1 + (0.012  RH)18)  h0 / 1 mm + 250  α3, 1500  α3) =
                                                  414.1
Concrete strength factor - exp.B.4                      βfcm = 16.8 / (fcm / 1 N/mm2) = 2.206
Initial time (days)                                     t0 = 2
Concrete age factor - exp.B.5                           βt0,release = 1 / (0.1 + t00.2) = 0.801
Notional creep coefficients - exp.B.2                   ф0,release = ф70  βfcm  βt0,release =
2.235 Final time (days)                                 t0 = 28
Concrete age factor - exp.B.5                           βt0,final = 1 / (0.1 + t00.2) =
0.488 Notional creep coefficients - exp.B.2             ф0,final = ф50  βfcm  βt0,final =
1.622 Loss due to creep
          σp,c = ((Ep / Ecm)  ф0,release  σc,QP) / (1 + (Ep  Ap / (Ecm  Ac))  (1 + Ac / Ic  zcp2)  (1 + 0.8  ф0,release)) = 83.6 N/mm2
b. Loss due to shrinkage
Ambient relative humidity                               RH = 50
                                                        RH0 =
                                                        100
Relative humidity ratio - exp.B.12                      βRH = -1.55  [1 - (RH / RH0)3] = -1.356
Compressive strength                                    fcmo = 10 N/mm2
Cement type coefficients - Appendix B.2                 αds1 = 4
                                                        αds2 = 0.12
Basic drying shrinkage strain - exp.B.11
                                                   scd,0 = 0.85  ((220 + 110  αds1)  exp(-αds2  fcm / fcmo))  10-6  βRH = -0.000379
Notional size coefficient - Table 3.3                   kh = 0.93
At infinte time, from exp.3.10                          βds,t,ts = 1
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Drying shrinkage strain at infinite time - exp.3.9 scd,t = βds,t,ts  kh  scd,0 = -0.000353
Autogenous shrinkage strain at infinite time - exp.3.12
                                                     sca,inf = 2.5  (fck / 1 N/mm2 - 10)  10-6 = 0.0001
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At infinte time,from exp.3.13                         βas,t = 1
Autogenous shrinkage strain - exp 3.11                sca,t = βas,t  sca,inf =
0.0001 Total shrinkage strain - exp.3.8               scs = -scd,t + sca,t =
0.000453 Loss due to shrinkage
                                 σp,s = scs  Ep / (1 + Ep  Ap / (Ecm  Ac)  (1 + Ac  zcp2 / Ic)  (1 + 0.8  ф0,release)) = 80.5 N/mm2
c. Loss due to relaxation
Maximum tensile stress minus immediate losses - cl.5.10.4(1)
                                                      σpi = σpm0 = 1180.3 N/mm2
Initial prestress ratio - cl.3.3.2(7)                 µ = σpi / fpk = 0.667
Time for long term relaxation losses (hours) - cl.3.3.2(8)
                                                      t = 500000
Absolute value of the relaxation losses of the prestress - exp.3.29
                                                   σpr = σpi  0.66  p1000  exp(9.1  µ)  (t / 1000)0.75  (1 - µ)  10-5 = 39.7 N/mm2
Loss due to relaxation
                                σp,r = 0.8  σpr / (1 + Ep  Ap / (Ecm  Ac)  (1 + Ac  zcp2 / Ic)  (1 + 0.8  ф0,release)) = 29 N/mm2
Total of time dependent losses
                                                      σp,c,s,r = σp,c + σp,s + σp,r = 193.1 N/mm2
Prestress after final losses                          σp0 = σpm0 - σp,c,s,r = 987.2 N/mm2
Final prestressing force                              Pp0 = σp0  Ap = 513.3 kN
Stresses caused by prestress and resistance moment in service
Stress in bottom fibre                                fbottom = Pp0 / Ac + Pp0  zcp  hna / Ic = 8.239 N/mm2
Stress in top fibre                                   ftop = Pp0 / Ac - Pp0  zcp  (h - hna) / Ic = 0.988
N/mm2 Quasi-permanent stress factor - cl.7.2(3) k2 = 0.45
Maximum permissible compress.stress - cl.7.2(3)                       σc,max = k2  fck =
22.5 N/mm2 Section modulus top                        Ztop = Ic / (h - hna) = 12937051
mm3
Resistance moment top                                 MR,top = (k2  fck - ftop)  Ztop = 278.3 kNm
Section modulus bottom                                Zbottom = Ic / hna = 6864558 mm3
Resistance moment bottom                              MR,bottom = (fctm + fbottom)  Zbottom = 84.5 kNm
Serviceability load                                   Fsls = Fswt + Ffin + Flive + Fpart = 9.165 kN/m2
Serviceability bending moment                         Msls = Fsls  bnom  Le2 / 8 = 14
                                                      kNm Msls / min(MR,bottom, MR,top)
                                                      = 0.166
                                                 PASS - Resistance moment is greater than serviceability bending moment
Ultimate moment of resistance
Characteristic strain of prestressing steel at maximum load - cl.3.3.6(7)
                                                      suk = 0.022222
Strain limit - cl.3.3.6(7)                            sud = 0.9  suk = 0.02
Strain due to prestressing                            sp0 = σp0 / Ep = 0.005062
Design tensile strength of prestressing steel - cl.3.3.6(6)
                                                      fpd = fp0.1k / yS = 1304.3 N/mm2
Strain at elastic limit - Fig 3.10                    sel = fpd / Ep = 0.006689
Stress at maximum load - Fig 3.10                     fpd,uk = fpk / yS = 1539.1 N/mm2
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Stress at limiting strain - Fig 3.10           fp,max = fpd + (fpd,uk - fpd)  (sud - sel) / (suk - sel) = 1505.5 N/mm2
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Depth to prestressing steel                              d = h - hcp = 115.4 mm
Stress distribution factor - exp.3.19                    λ = 0.8
Stress block factor - exp.3.21                           η=1
Depth of neutral axis, by iteration                      x = 32.5 mm
Depth to centroid of concrete in compression dn = 0.5  λ  x = 13 mm
Change in stress                                         sp = scu3  (h - hcp) / x - scu3 = 0.009
Final strain in tendons                                  sp = sp + sp0 = 0.013992
Final stress in tendons                                  fp = min(fpd + (fpd,uk - fpd)  (sp - sel) / (suk - sel), fp,max) = 1414.7 N/mm2
Force in tendons                                         Fp = fp  Ap = 735.7 kN
Area of concrete                                         Ac,tf = btf  λ  x = 25964 mm2
Force in concrete                                        Fc = Ac,tf  η  fcd = 735.7 kN
Ultimate moment of resistance                            MR = Fc  (d - dn) = 75.3 kNm
Ultimate load                                            Fuls = Fswt  yG + Ffin  yG + Flive  yQ + Fpart  yQ = 13.123 kN/m2
Ultimate bending moment                                  Muls = Fuls  bnom  Le2 / 8 = 20.1
                                                         kNm Muls / MR = 0.267
                                                          PASS - Resistance moment is greater than ultimate bending moment
Shear resistance
a. Cracked sections
Shear stress constant                                    CRd,c = 0.18 / yC = 0.12
Reinforcement depth factor - cl.6.2.2(1)                 k = min(1 + (200 mm / d), 2.0)
= 2 Reinforcement ratio - cl.6.2.2(1)                    pl = min(Ap / (bw,t  d), 0.02) =
0.013
Axial force in cross-section                             NEd = Ap  σp0 = 513.3 kN
Stress in concrete section                               σcp = min(NEd / Ac, 0.2  fcdv) = 3.501 N/mm2
Minimum shear stress                                     vmin = 0.035 N/mm2  k3/2  (fck / 1 N/mm2)1/2 = 0.7 N/mm2
Maximum stress factor - cl.6.2.2(1)                      k1 = 0.15
Shear resistance for cracked section - exp.6.2a & 6.2b
                                VRd,c,c = (max(CRd,c  k  (100  pl  fck / 1 N/mm2)1/3 1 N/mm2, vmin) + k1  σcp)  bw,t  d = 60.3 kN
Ultimate shear force                                     Vuls = Fuls  bnom  Le / 2 = 23 kN
Extent of cracked section, point at which bottom fibre stress equals design tensile strength, by iteration
                                                         x = 1750 mm
Moment at x;                                             Mx = Vuls  x - Fuls  bnom  x2 / 2 = 20.1 kNm
Shear at x                                               Vx = Vuls - Fuls  bnom  x = 0 kN
Bottom fibre stress at x
        fb = Mx / Zbottom + Vx  cos(45) / Ac - Pp0 / Ac - Pp0  zcp / Zbottom + Vuls / (0.7  Ac) + Vuls  hna / (0.7  Zbottom) = -4.619
        N/mm2
                                                         Vx / VRd,c,c = 0
                                                                                 PASS - Section is uncracked throughout its length
b. Uncracked sections
Distance of section from starting point of transmission length - cl.6.2.2(2)
                                                         lx = lb + hna = 198 mm
Tendon release factor - cl.8.10.2.2(2)                          α1 = 1
Cross-section factor - cl.8.10.2.2(2)                    α2 = 0.19
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Average strand diameter                         ф s1) / (Ns1) = 9.3 mm
                                      фav = (10 ф
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Tendon coefficient - cl.8.10.2.2(1)                   ηp1 =
3.2 Bond condition coefficient - cl.8.10.2.2(1) η1 = 1
Design value of tensile strength at release -
cl.8.10.2.2(1)
                                                      fctd,t = αct  0.7  fctm,t / yC = 0.957 N/mm2
Bond stress at transfer - exp.8.15                    fbpt = ηp1  η1  fctd,t = 3.064 N/mm2
Basic value of transmission length - exp.8.16 lpt = α1  α2  фav  σpm0 / fbpt = 680.7
mm Upper bound value of transmission length - exp 8.18
                                                      lpt2 = 1.2  lpt = 816.9 mm
Length ratio - cl.6.2.2(2)                            αl = lx / lpt2 = 0.242
Shear resistance for uncracked section - exp.6.4 VRd,c,u = (Ic  bw,t / Sc)  (fctd2 + αl  σcp  fctd) = 82.3 kN
                                                      Vuls / VRd,c,u = 0.279
                                                                   PASS - Shear resistance is greater than ultimate shear force
Resistance to spalling for prestressed hollowcore slabs - EN 1168 cl.4.3.3.2.1
Section modulus of bottom fibre                       Wb = Ic / hna = 6864558 mm3
Core radius                                           k = Wb / Ac = 46.8 mm
Initial prestressing force in a single web            P0 = σpm0  Ap,s1 = 61.4 kN
Eccentricity of prestressing steel                    e0 = hna - cs1 - фs1 / 2 = 63.4
mm
Alpha factor                                          αe = max((e0 - k) / h , 0) = 0.110187
Basic value of transmission length - exp.8.16 lpt = α1  α2  фs1  σpm0 / fbpt = 680.7
mm Lower bound value of transmission length                  lpt1 = 0.8  lpt = 544.6 mm
Spalling stress
                                     σsp = (P0 / (bw,i  e0))  (15  αe2.3 + 0.07) / (1 + (lpt1 / e0)1.5  (1.3  αe + 0.1)) = 0.646
                                     N/mm2
                                                      σsp / fctk,0.05,t = 0.45
                                                                    PASS - Axial tensile strength is greater than spalling stress
Serviceability
Stress limitations
Max.compressive stress at transfer - exp.5.42                  σc = 0.60  fck,t = 12.735 N/mm2
Compressive stress at transfer                        fc,t = P / Ac + P  zcp / Zbottom = 10.29
N/mm2
                                                      fc,t / σc = 0.808
                                       PASS - Maximum compressive stress is greater than compressive stress at transfer
Maximum tensile stress at transfer                             σt = fctm,t = 2.052 N/mm2
Self-weight moment                                    Mswt = Fswt  bnom  Le2 / 8 = 5.612 kNm
Tensile stress at transfer                            ft,t = max(P  zcp / Ztop - P / Ac - Mswt / Ztop, 0 N/mm2) = 0
                                                      N/mm2 ft,t / σt = 0
                                                    PASS - Maximum tensile stress is greater than tensile stress at transfer
Max.compressive stress due to characteristic loads                   σc,c = 0.45  fck =
22.5 N/mm2 Compressive stress due to characteristic loads                        fc,c = ftop +
Msls / Ztop = 2.072 N/mm2
                                                      fc,c / σc,c = 0.092
                     PASS - Maximum compressive stress is greater than compressive stress under characteristic loads
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Max.tensile stress due to char.loads - cl.7.3.2(4) σt,c = fct,eff = fctm = 4.072 N/mm2
Tensile stress due to characteristic loads       ft,c = max(Msls / Zbottom - fbottom, 0 N/mm2) = 0 N/mm2
                                                 ft,c / σt,c = 0
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                                  PASS - Maximum tensile stress is greater than tensile stress under characteristic loads
Deflection
a. Initial camber
Camber due to prestress                                δ0,p = Ap  σpm0  zcp  Le2 / (8  Ecm,t  Ic) = 2.916 mm
Deflection due to self weight                          δ0,G = 5  Fswt  bnom  Le4 / (384  Ecm,t  Ic) = 0.351 mm
Initial camber                                         δ0 = δ0,p - δ0,G = 2.565 mm
Deflection limit                                       δ0,limit = Le / 200 = 17.5 mm
                                                       δ0 / δ0,limit = 0.147
                                                                                     PASS - Initial camber is within acceptable limits
b. Camber after installation
Variation in initial camber due to prestress over time
Coefficient of development of viscous effect in time
Initially, at 0 days                                   αt0 = 0.1
At installation, after 1 month                         αt1 = 0.4
                                                       фtinf,t0 =
                                                       2.5
Concrete viscosity coefficient between time t0
and t1
                                                       фt0,t1 = фtinf,t0  (αt1 - αt0) = 0.75
Variation in initial camber due to prestress
over time
                                 δ1,p = δ0,p  (1 + Ecm,t  2 / (Ecm,t + Ecm)  фt0,t1) + (Pp0 - Pm0)  zcp  Le2 / (8  Ecm  Ic) = 4.491 mm
Deflection due to self-weight                          δ1,G = 5  Fswt  bnom  Le4 / (384  Ecm  Ic) = 0.286 mm
Variation of deflection due to self-weight over time δ1,фG = δ0,G  (Ecm,t  2 / (Ecm,t + Ecm)  фt0,t1) =
0.236 mm Camber after installation                     δ1 = δ1,p - δ1,G - δ1,фG = 3.969 mm
Deflection limit                                       δ1,limit = Le / 300 = 11.667 mm
                                                       δ1 / δ1,limit = 0.34
                                                                    PASS - Deflection after installation is within acceptable limits
c. Long term deflection
Coefficient of development of viscous effect in time
At installation, after 1 month                         αt1 = 0.4
Application of live loads, after 3 months              αt2 = 0.6
Finally                                                αt,inf = 1
Concrete viscosity coefficient between time t1 and t2
                                                       фt2,t1 = фtinf,t0 * (αt2 - αt1) = 0.5
Concrete viscosity coefficient between time t2 and tinf
                                                       фtinf,t2 = фtinf,t0 * (αt,inf - αt2) = 1
Concrete viscosity coefficient between time t1 and tinf
                                                       фtinf,t1 = фtinf,t0 * (αt,inf - αt1) = 1.5
Concrete aging coefficient                      p = 0.8
Variation in initial camber due to prestress between time t1, installation and time tinf
                                                       δinf,фp = p  фtinf,t1  Ap  σp0  zcp  Le2 / (8  Ecm  Ic) = 2.383 mm
Viscous effects of self-weight from time t1, installation to time t2, application of live loads
                               Project                                                             Job Ref.
                               Section                                                             Sheet no./rev.
                                                                                                    14
                               Calc. by      Date             Chk'd by           Date              App'd by         Date
                               Abdullahi
                               Yusuf
                                             δ2,фG,G1 = 5  Fswt  bnom  Le4  фt2,t1 / (384  Ecm  Ic) = 0.143 mm
Elastic deflection for permanent and long-term variable loads
                                 Project                                                                    Job Ref.
                                 Section                                                                    Sheet no./rev.
                                                                                                             15
                                 Calc. by           Date              Chk'd by           Date               App'd by         Date
                                 Abdullahi
                                 Yusuf
                                             δ2,Qperm,Qinf = 5  (Ffin + ψ2  (Fpart + Flive))  bnom  Le4 / (384  Ecm  Ic) = 0.156
mm Viscous effects of all permanent loads from time t2, application of live loads to time tinf
                              δinf,фG,Q = 5  bnom  (Fswt + Ffin + ψ2  (Fpart + Flive))  Le4  p  фtinf,t2 / (384  Ecm  Ic) = 0.353 mm
Long term deflection                                δinf = δ2,фG,G1 + δ2,Qperm,Qinf + δinf,фG,Q - δinf,фp = -1.731 mm
Deflection limit                                    δinf,limit = Le / 500 = 7
                                                    mm abs(δinf) / δinf,limit
                                                    = 0.247
                                                                       PASS - Long term deflection is within acceptable limits
Final deflection                                    δfinal = δ1 + δinf = 2.238 mm