Counterfort Abutment [PDF]

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SALIENT FEATURES OF THE BRIDGE : Span c/c of brg. c/L of brg. c/L of exp. J Exp. Gap Overall span skew Depth of super-structure Wearing Coat thickness Depth of Bearing + Pedestal (minimum)



= = = = = = = =



Overall carriageway width Clear carriageway width Cross Camber Lenth of Abutment MATERIAL USED & THERE PROPERTIES : CONCRETE Grade of Concrete Mean value of concrete compressive strength Design Concrete compressive strength



fck fcm fcd



Secant Modulus of Elasticity Mean axial tensile strength



Ecm fctm



33.44 0.780 100.000 34.9 0 2.425 53 350



= = = =



m m mm m deg m mm mm



25 m 24 m 2.50% 30 m



= = = = = =



M 35 45 0.447 15.63 32308.25 3.46



Mpa Mpa *fck MPa MPa Mpa



= = = =



Fe 500 0.870 434.8 200000



Mpa *fyk Mpa Mpa



REINFORCING STEEL Grade of Reinforcement Design yield strength of reinforcement



fyk fyd



Modulus of Elasticity



Es



RCC Density



3 2.5 t/m



=



ANALYSES ASSUMPTION Enviromental parameters Relative humidity Exposure condition Modulus of Elasticity for Concrete For short Term loading For long Term loading f = Creep coefficent Creep coefficent for Foundation



Ecm Ecm'



= =



60 % Moderate



= =



32308.25 Mpa Ecm/ (1+f)



f



=



1 ( As ho = ¥ , For foundations)



Ecm'



=



16154.125 Mpa



Ac



= = = = = = @ =



0.00 0.00 #DIV/0! 90 25550 1.45 1.59 12463.4



Creep for abutment shaft Cross-sectional Area Perimeter in contact with atmosphere u Notational size ho Age of concrete at the time of loading to t¥ considered



2Ac/u



f (¥,90) Ecm'



m2 m mm days days (Refer Appendix B) *(Increased by 10% on the conservative side) 2 N/mm



SERVICEABILITY LIMIT STATE : Max permissible Stress in Concrete Rare Combination Quasi permanent Combination



= =



0.48*fck 0.36*fck



= =



16.8 Mpa 12.6 Mpa



Max permissible Stress in Steel



=



0.8*fyk



=



400 Mpa



Permissible crack width



wk,max



=



0.3 mm



Backfill Soil Parameter f d dsubmerged=



= =



i gdry



30 20.00 10.00



o



Angle of internal friction, Angle of friction between soil and concrete 1/2 d dry



= = =



= =



Surcharge angle Dry density of earth



= =



gsat



=



Saturated density of earth



=



0o 3 2.2 t/m 3 2.2 t/m



gwater



=



water density



=



3 1 t/m



o o



gsub



= =



m



Submerged density of earth coeff. Of friction b/w footing base & earth



Live Load Surcharge : Equivelent to Live Load surcharge intensity q



1.2



m Earth Fill =



SEISMIC PARAMETER Seismic Zone Type of soil Zone factor Importance factor Response Reduction Factor, Rlong.



3



1 t/m 0.8



= =



2 2.64 t/m



= = = = =



Z I



II rocky #N/A 1.2 2.5



Response Reduction Factor, Rtrans.



=



1



Response Reduction Factor, Rvert.



=



2.5



LEVEL DETAILS : Formation level Ground Level Bearing capacity



= = =



HFL level MSL



= = =



213.435 m 202.083 m 2 35.00 t/m 2 43.75 t/m 204.000 202.083 m



*/( Working State, Non-Seismic case) */( Working State, Seismic Case)



25.0 0.50



0



24.000



0.50 0.053 thick WC FRL : 213.435 2.5%



2.425



0.350 2.3



Cap Top :



3.4 c/c of girder Nos. of Girder C/c of Girder Top Flange Width



= = =



7 3.4 1



Nos. m m



Sign Convention : T MTT MLL



L



Y Showing +ve Force & Moment Direction Transverse Section of Structure 0.3 0.83



FRL :



213.435



Cap Top :



210.2945



HFL :



204.000



LWL :



202.083



GL



202.083



FDN:



197.083



0.57



1.7 0.5



16.352



1.43



0.27 0.6 11.7



5 Heel



Toe 5.0



1



A1/A2 210.2945



6



3 30



2.5



2.5



2.5



2.5



3



0.6



6



0.9 No. of CounterfortsEarth side Internal = External =



10.0 2.0



Nos. Nos.



0.9