ACES PSC Design Module V{VERSION}: Run date: {DATE}
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Heading: {PROJECT}
Job Name: {JOBNAME}
Designer: {DESIGNER}
Comments: {COMMENT1}
Units: mm, microstrain, kN, kN.m, MPa
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DESIGN CODE: {CODE} {DEC 0}
PRESTRESS LOSSES
| Initial jacking force (Pj) |
= |
{Pj} |
kN {DEC 3} | ||
| Jacking force factor (Jf) |
= |
{Jf} |
|||
| Loss due to Steam Relaxation | |||||
| The steam relaxation factor (k5) is the larger of 0.0 or: | |||||
| The maximum of: k5a = 1 + (Jf-0.7)*0.5/0.1 |
= |
{k5a} |
({CODE} (Fig 6.3.4)) | ||
| and: k5b = (Jf-0.4)/0.3 |
= |
{k5b} |
|||
| Steam relaxation factor (k5) |
= |
{k5} |
|||
| Loss due to relaxation (Lsrl = 0.1*k5/1.5) |
= |
{Lsrl} |
{DEC 1} | ||
| Loss in PS due to relaxation (Prl = - Lsrl*Pj) |
= |
{Prl} |
kN | ||
| Loss as a proportion of Pj (Lsr = - Prl*100/Pj) |
= |
{Lsr} |
% | ||
| PS force remaining (Pjr = Pj + Prl) |
= |
{Pjr} |
kN | ||
| Elastic Deformation Loss | |||||
| Area of PS steel (Ap = Nbbars*Pi*Ds^2/4) |
= |
{Ap} |
mm^2 | ||
| Mean Young's Modulus of girder concrete (Egmt) |
= |
{Egmt} |
MPa | ||
| Young's Modulus of stressing steel (Ep) |
= |
{Ep} |
MPa | ||
| Area of girder (Ag) |
= |
{Ag} |
mm^2 {EXP 4} | ||
| Moment of inertia of girder (Ig) |
= |
{Ig} |
mm^4 {DEC 01} | ||
| Dist between CG girder and CG of strands (e) |
= |
{e} |
mm | ||
| Moment due to girder selfweight (Msw) |
= |
{Msw} |
kN.m | ||
| Stress at CG of strand group: | {DEC 2} | ||||
| fcgs = - Pjr*1000*(1/Ag + e^2/Ig) + Msw*10^6*e/Ig |
= |
{fcgs} |
MPa {DEC 1} | ||
| Elastic deformation loss: | |||||
| Pelastic = - fcgs*Ep*Ap/(Egm*1000) |
= |
{Pelastic} |
kN.m | ||
| Loss as a proportion of Pj (Ledl = - Pelastic*100/Pj) |
= |
{Ledl} |
% | ||
| PS force at transfer (Pt = Pjr + Pelastic) |
= |
{Pt} |
kN | ||
| PS at transfer as a proportn of Pj (Ltr = Pt*100/Pj) |
= |
{Ltr} |
% | ||
| Shrinkage Loss | {DEC 1} | ||||
| Shrinkage strain (us) [Figure 6.1.7] |
= |
{us} |
microstrain {DEC 3} | ||
| Modular ratio (n = Es/Eg) |
= |
{n} |
{DEC 0} | ||
| Area of longitudinal reinforcement (Arft) |
= |
{Arft} |
mm^2 | ||
| Area of composite girder (Ac = n*As + Ag) |
= |
{Ac} |
mm^2 | ||
| {DEC 1} | |||||
| Loss in PS due to shrinkage: | |||||
| Pshr = - us*Ep*Ap*10^-9/(1 + 15*Arl/Ac) |
= |
{Pshr} |
kN ({CODE} Clause 6.4.3.2) | ||
| Loss as a proportion of Pj: (Lshr = - Pshr*100/Pj) |
= |
{Lshr} |
% | ||
| PS force remaining after shrinkage: (Prs=Pt+Pshr) |
= |
{Prs} |
kN | ||
| Creep Loss due to Prestress & Self-Weight | |||||
| Moment due to girder self-weight (Msw) |
= |
{Msw} |
kN.m {EXP 4} | ||
| Area of composite girder (Ac) |
= |
{Ac} |
mm^2 {DEC 0} | ||
| Exposed girder perimeter (Gp) |
= |
{Gp} |
mm | ||
| Void perimeter (Vp) |
= |
{Vp} |
mm | ||
| Young's Modulus of girder at 28 days (Eg) |
= |
{Eg} |
MPa {DEC 1} | ||
| Mean girder concrete strength at transfer (f'cmt) |
= |
{f'cmt} |
MPa | ||
| 28 day girder concrete strength (f'cg) |
= |
{f'cg} |
MPa {DEC 2} | ||
| Theoretical thickness (th = 2*Ac/(Gp + 0.5*Vp)) |
= |
{th} |
({CODE} Clause 6.1.7) | ||
| Ratio of concrete strengths (Fratio = f'cmt/f'cg) |
= |
{Fratio} |
|||
| Basic creep factor (Øccb) |
= |
{Occb} |
({CODE} Table 6.1.8a) | ||
| Creep coefficient (k2) |
= |
{k2} |
({CODE} Figure 6.1.8a) | ||
| Creep coefficient (k3) |
= |
{k3} |
({CODE} Figure 6.1.8b) | ||
| Design creep factor (Øcc = Øccb*k2*k3) |
= |
{Occ} |
({CODE} Clause 6.1.8.2) {DEC 2} | ||
| Creep stress at CG of strand group: | |||||
| fcscgs = -Pt*1000(1/Ag + e^2/Ig) + Msw*10^6*e/Ig |
= |
{fcscgs} |
MPa {DEC 1} | ||
| Creep strain at CG of strand group: | |||||
| ucc1 = fcscgs* Øcc/(Eg*10^6) |
= |
{ucc1} |
microstrain | ||
| Creep Loss due to Deck & Superimposed Loads | {DEC 1} | ||||
| Deal load moment of concrete slab (Mslab) |
= |
{Mslab} |
kN.m | ||
| Moment due to superimposed loads (Msdl) |
= |
{Msdl} |
kN.m {EXP 4} | ||
| Moment of inertia of girder (Ig) |
= |
{Ig} |
mm^4 | ||
| Moment of inertia of composite sectn (Ic) |
= |
{Ic} |
mm^4 {DEC 1} | ||
| Height to centroid of girder (Yb) |
= |
{Yb} |
mm | ||
| Height to centroid of composite sectn (Yc) |
= |
{Yc} |
mm | ||
| Height to CG of strand group (Ycgs) |
= |
{Ycgs} |
mm {DEC 2} | ||
| Stress at CG due to concrete deck: | |||||
| Fdeck = Mslab*10^6*(Yb - Ycgs)/Ig |
= |
{Fdeck} |
MPa | ||
| Stress at CG due to superimposed DL: | |||||
| Fsdl = Msdl*10^6*(Yc - Ycgs)/Ic |
= |
{Fsdl} |
MPa {DEC 0} | ||
| Youngs Modulus of insitu slab concrete (Es) |
= |
{Es} |
MPa {DEC 2} | ||
| Ratio of concrete strengths (Fratio = f'cmt/f'cg) |
= |
{Fratio} |
|||
| Basic creep factor (Øccb) |
= |
{Occb} |
({CODE} Table 6.1.8A) | ||
| Creep coefficient (k2s) |
= |
{k2s} |
({CODE} Figure 6.1.8A) | ||
| Creep coefficient (k3s) |
= |
{k3s} |
({CODE} Figure 6.1.8B) | ||
| Design creep factor (Øcc2 = Øccb*k2s*k3s) |
= |
{Occ2} |
({CODE} Clause 6.1.8.2) {DEC 1} | ||
| Creep strain at CG of strand group: | |||||
| ucc2 = Øcc2*10^6*(Fdeck+Fsdl)/Eg |
= |
{ucc2} |
microstrain | ||
| Total creep strain: | |||||
| ucc = ucc1 + ucc2 |
= |
{ucc} |
microstrain | ||
| Summary of Creep Losses | {DEC 1} | ||||
| Loss in PS due to creep (Pcreep = - ucc*Ep*Ap/10^9) = |
{Pcreep} |
kN | |||
| Loss as a proportion of Pj (Lcr = Pcreep*100/Pj) = |
{Lcr} |
% | |||
| Total remaining prestress force (P = Pt - Pshr - Pcreep) = |
{P} |
kN | |||
| Total loss of PS as a proportion of Pj (Ltt = P*100/Pj) = |
{Ltt} |
% | |||
| Summary of Prestress Losses | |||||
|
Force (kN) |
%Pj |
|
| JACKING FORCE (Pj) |
{Pj} |
100 |
| Loss in PS due to relaxation |
{Prl} |
{Lsr} |
| Loss in PS due to elastic deformation |
{Pelastic} |
{Ledl} |
| TRANSFER FORCE (Pt) |
{Pt} |
{Ltr} |
| Loss in PS due to shrinkage |
{Pshr} |
{Lshr} |
| Loss in PS due to creep |
{Pcreep} |
{Lcr} |
| FINAL PS FORCE (P) |
{P} |
{Ltt} |