file:///home/webmaster/mojo/converter/data/uploads/vy3b8181hmifhs7c/o_1cg0mupo01i7h1gci173k1uc715963i/tmp.xls Page 1 of 5Enter company name Project: PROJECT ????. Engineer: YP Project #
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Enter company name Project: PROJECT ???? Engineer: YP Project #
Date: 06/15/18
Preliminary Design Of Prestressed Precast Concrete Bridge Girder With Cast-In-Place Concrete Composite Deck
( Design Code: AASHTO LRFD 4th Edition, 2007 )
Materials
Concete Properties
0.155 kip/ft³
Prestressing Steel Properties
Strand type = Low relaxation Tensile strength, fs = 270ksi Modulus of elasticity, Ep = 28,500ksi Strand diameter = 0.5in Single strand area = 0.153 in²
Geometry
General
Clear span or brg-to-brg, L = 72ft Girder spacing, S = 7.5ft
7in Sacrificial deck depth = 0.5
Average annual relative humidity, H = 80%
Conc pad thickness above top flange = 2.5in (used for concrete weight calculations only)
Precast girder properties
Girder label = W42G
42.0 in 374.0 in² 76,437 18.89 in Top flange width = 15.00 in
Composite girder properties
1.25
845 in² 226,038 33.73 in
Loads
Noncomposite Dead Loads, k/ft
0.403 Moment due to all non-composite loads @ 1/2 span
Haunch = 0.04036 Moment due to girder weight @ strands harp point (X=24 ft)
1.269 k/ft Composite Dead Loads, k/ft
Overlay = 0.13 Moment due to composite loads @ 1/2 span
Diaphragms, etc = 0.05
0.560 k/ft Live Loads (HL93)
1,773 k-ft Comment:
k-ft Lane distribution factor, DF = 0.647 Live load moment per girder, M(L+I) = 1,148 k-ft
Formula for
PSGSimple
Compressive strength,
ksi
Modulus of Elasticity, ksi
Concrete unit weight, c =
Effective deck thickness, teff =
in (additive to teff) Effective deck width, beff =
Depth, Hg = Area, Ag = Moment Inertia, Ig = in4 Centroid from bottom, yb =
n = Ec/Ecd =
Ac = Ac = Ag+teffbeff/n
Ic = in4 Ic = Ig+Ag(yb-ybc)²+beffteff³/12/n+beffteff(Hg+teff/2-ybc)²/n
ybc = ybc = (Agyb + teffbeff(Hg+teff/2)/n)/Ac
Girder, wg =
MD = wDL²/8 =
M = wgX(L-X)/2 =
Total w D =
MCD = WCDL²/8 = Overwrite MCD =
Total w CD =
Moment due to a lane of HL93 , ML1 =
Overwrite ML1 =
ML1 =(0.64)L²/8+1.33[32.0(L/2-2.333)(L-9.333) + 8.0(L/2-16.333)(L/2+2.333)]/L
teff
beff
sacrificial deck depth
Hg straight strands
harped strands temporary strands
haunch
Leave blank if agree with
b ef value
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Enter company name Project: PROJECT ???? Engineer: YP Project #
Date: 06/15/18
PSGSimple
Prestressing
270 x 0.75 = 202.5 ksi (31 kip per strand)
No strands C.G from bottom, in
Prestressing after losses ksi 178.0 152.8 Prestressing force in one strand kip 27.2 23.4
Stresses
Final prestressing force -655 -867 -4.322 1.395
OK
OK Stresses
N.G.
OK
Stress calculation formulas Noncomposite loads
Composite loads
Stress in prestressing strands prior to transfer, fpi =
Strands layout @ midspan
@ Final
Strands c.g from girder soffit, ys Eccentricity to girder centroid, em
Prestressing force, Pps Prestressing moment, Mps = Ppsem
Stress Check ("+" for tension, "-" for compression)
√f'c =
f'c =
f'ci =
0.0948√f'ci<= 0.2
bottom = P/Ag+(12M/Ig)yb top = P/Ag+(12M/Ig)(yb-Hg) bottom = P/Ac+(12M/Ic)ybc top = P/Ac+(12M/Ic)(ybc-Hg)
For prestressing losses see calculations on the right
Trang 3GIRDER PROPERTIES DATABASE
Label in in^2 in^4 in in in^3 in^3
Trang 4Iy Btop in^4 in
49 49 49 49 49 15 20 25 43
Trang 5Engineer: Sheet: GirderPropertiesCalculator File: tmp.xls
PROPERTIES OF SECTION DESCRIBED BY LAYERS (FROM TOP TO BOTTOM)
Units: in
Layer No Top Width Thickness
Bottom Width
Distance from top
Ix =
yt =
Yb =
St =
Sb =
Iy =
H = t Area = (bb+bt)t/2
Ix = t[bt(y+t/2-yt)² + (bb+2bt)t²/36 + (bb-bt)(y+(2/3)t-y
yt =(1/A) t[(bt+2bb)t/6+(bt+bb)*y/2]
-60 -50 -40 -30 -20 -10 0
Copy properties to Girder worksheet