Slab design 2.57.0)Design of slab7.0)Analysis & Design of
Precast slab above Road Beam at RP1 to RP47.1)General Details
:Width of slab Panel=5.000mWidth of slab Panel without
ledge(5-0.287-0.288)=5.000mLength of slab Panel=4.630mBearing below
slab on Road beam @ North side=0.000mBearing below slab on
Retaining wall=0.000mDeck slab depth=0.30mEffective Deck slab
depth(300- 40- 0.5*20)=250.0mmslab cantilevering out of
beam=0mmEffective Span of simply supported slab
=(4.63-0-0+0.25-0)=2.500mWearing coat thickness=0.106mConcrete
density=25kN/m3Wearing coat material density=24kN/m3Concrete
GradeSlabfck=30MpaReinforcementfy=500MpaArea of crash
barrier=0.33m2Fill height=1m7.2)Loading & Design forces:7.2.1)
Dead LoadsUniformly distributed load for per metre width for dead
load due to self weigth of slab and SIDL due to wearing coat and
its Bendingmoment and Shear force at distance d from face of
support are tabulated below. Crash barrier is present at both end
of slab whereslab are supported on beam on one side andon retaining
wall on other side. Hence crash barrier load will not cause any
bending inslab.Table - 1 ; Design UDL and BM & SF for Dead Load
& SIDLLoad typeMax Uniformly distributed load (kN/m)Max Midspan
moment (kNm)Max shear force @ centre of support (kN)Max Shear force
@ distance d from face of support (kN)ResultResultResultDead
Load(0.3x25) =7.57.5x2.5^2 / 867.5x2.5 / 296SIDL due to wearing
coat(0.106x24) =2.542.544x2.5^2 / 822.544x2.5 / 232Fill(1x24)
=24.0024x2.5^2 / 81924x2.5 / 23020Total342743292.5000.00.027 kNm43
kN29 kN0.4000.40029 kN43 kN7.2.2) Live LoadsLive Load for different
vehicles (i.e. IRC 70R Wheeled, IRC 70R Tracked, IRC Class A &
40T boggie) are placed symmetrically onspan to get maximum bending
moment & nearer to support to get maximum shear force are
tabulated below: -a)IRC 70R TRACKED VEHICLE :-255Load of tracked
vehicle =70 Tons25.02.500Length of tracked vehicle =4.57
mDispersion in longitudnal direction =. 4.57 + 2* 16.57 mVehicle
width in transverse direction2.90 mDispersion in transverse
direction =. 2.9 + 2* 14.90 mAs the length of tracked vehicle is
greater than span width, ie. 4.57 > 2.5Load of axle will be
taken proportionately 2.5/4.57*70 = 38T109Impact factor =2500.0
%Load intensity per square m= 70*9.81*(1+25/100) / ( 6.57*4.9 )26.7
KN/m2i) Bending moment calculationEffective width of slab is
computed using equation = beff = a (1 - a / lo ) + bw (Ref IRC
21:2000 Cl 305.16.2)lo = effective span of slab =2.50 ma = distance
of cg of concentrated load from nearest support =0.63 mbw = breadth
of concentration area of load including wearing coat thickness
=1.06 m = constant depending upon ratio of b / lo =b/lo= 5.0/
2.50023.00beff =3*0.625* (1-0.625/2.5) +1.062=2.47 mHowever maximum
length of slab panel width without ledge ==5.00 mEffective width of
dispersion for 2 tracks =2.47/2+0.86/2+1.2+0.86/2+0/2 =4.53 mWheel
dispersion does not overlaps =0x 0.0002.05 / 2 = 1.03m0Intensity of
load per metre width =(0) / (2.5*4.53)=0 kN/sq m2.050 kN0 kN4.5727
kN/m27 kN/m1.25.000.852.500Va = 33 kN2.5Vb = 33 kN2.50021 kNmii)
Shear Force calculationMaximum shear force is obatined for the same
laoding condition0.00 m0.00 m2.5000.00.0Load dispersion length
along span wise =0.00 m0beff =0=0.00 mHowever maximum length of
slab panel width without ledge ==5.00 mConsider dispersion length
of load along longitudinal direction ==0.00 mIntensity of load per
square metre =0=0 kN/sq mIntensity of load per metre width =0x 1=0
kN/m23 kN0.4000.4002.500Va = 23 kNVb = 23 kNb)IRC 70R WHEELED
VEHICLE :-IRC Wheeled vehicle consists of 7 axles, However in span
of 2.5m only 3 axles can be accomodated.Axle No. 1 =12 TonsAxle No.
2 =17 TonsAxle No. 3 =17 TonsImpact factor =2500.0 %2.131.37Total
Live Load on the slab panel =12+17+17=46 TonsLoad on one side
wheels including impact factor =46 Tons/2x 1.250x 9.81 =282 kNi)
Bending moment calculationEffective width of slab is computed using
equation = beff = a (1 - a / lo ) + bw (Ref IRC 21:2000 Cl
305.16.2)lo = effective span of slab =2.50 ma = distance of cg of
concentrated load from nearest support =0.29 mbw = breadth of
concentration area of load including wearing coat thickness =1.07 m
= constant depending upon ratio of b / lo =b/lo= 5.0/
2.50022.26beff = for single wheel2.26*0.285* (1-0.285/2.5)
+1.072=1.64 mEffective width of dispersion for 3 wheels
=1.65/2+0.86/2+2.13+1.37+0.86/2+1.65/2 =6.00 mHowever maximum
length of slab panel width without ledge ==5.00 mConsider
dispersion length of load along longitudinal direction ==5.00
mConsider effective width of one wheel load =0.86 + 2 * 0.106 =1.07
mWheel dispersion does not overlaps =1.08 / 2 =
0.54m1.50Eccenticity from 'A'0=0.00mEccenticity from C.G. of
base0=0.000mb)FOS against sliding0x 0=0.00>1.2500c)Check for
pressure :Width of Wall @ base =0.00mP/A
=0=0.0kN/m2M/Z0=0.0kN/m2Over burden pressure below Bed
=0.000kN/m2Maximum pressure =P/A + M/Z=0kN/m2Net pressure-
0=0kN/m20Minimum pressure =P/A - M/Z=0kN/m207.6.3)Design of
Abutment @ Height0.00 mfrom Retaining Wall top7.6.3.1)0stem depth
=0.00 mLoadLoad in kNL.A @ BMoment(kN)(kN-m)00x 0.0000.00.000000x
0.0000.00.000000x 0.0000.00.000000x 0.0000.00.000000x
0.0000.00.0000Slab load0x 0.0000.00.00000x 0.0000.00.00000x
0.0000.00.00000x 0.0000.00Total0.00Horizontal Force due to braking
(50% in EQ case)00.000Unbalanced Longitudinal moment due to LL at
wall bottom0Dynamic increment in Earth pressure
:P10.0000.002.00.00.0000P20.00x 0.0x 1.000.00.0000P30.00x 0.0x
1.000.00.0000Total00PassivePp0.0x 0.0x 0.50.00.0007.6.3.2)Load
summary under EQ condition without LL & 50% surcharge :Total
vertical load00kN00kN-m00kN00kN-mNet stabilizing
moment=0kN-m7.6.3.3)Stability Check :a)FOS against
overturning0=0.00>1.50Eccenticity from 'A'0=0.00mEccenticity
from C.G. of base0=0.000mb)Check for Shear0/ 0.000.00kN/m2b)Check
for pressure :Width of STEM =0.00mP/A
=0=0.0kN/m2M/Z0=0.0kN/m2Permissible concrete stressesRef
IRC21:2000, Tab 9 & 11Maximum pressure =P/A + M/Z== 0kN/m25000
kN/sq mt0Minimum pressure =P/A - M/Z== 0kN/m2-530 kN/sq mt0
&LShirish Patel and AssociatesConsultants Private
Limited&RDELHI RAIL CORPORATION LTD.JAIPUR METRO RAIL
PROJECTSTAGE-1 (JP/EW/C2)&L&F&R&A