Design of ring beam foundation for 8mØ, 8m height tanks for Reliance Industries Limited Modernisation of existing terminal at Rewari to facilitate 20 percent ethanol blending Reference documents i) Soil report of Rewari site done by Kunika Geotechnical Services in September 2017 ii) Survey maps of Rewari site 1. Design parameters Internal angle of friction assuming filling with murrum ɸ degrees = Shell radius of tank m Shell diameter of tank m Tank height m Soil density kN/cum (Kunika Geotechnical Service's report dated September 2017) Bearing capacity of soil kN/sq.m (Kunika Geotechnical Service's report dated September 2017) Coefficient of friction between crushed rock and concrete Minimum depth of foundation required m 2. Initial proportioning Assumed depth of foundation m (FGL to BOC of raft) Assumed thickness of wall m Assumed width of raft m Assumed thickness of raft m Assumed projection of wall above FGL m Assumed height of wall (TOC of wall to TOC of raft) m Total wall height (stem+ raft thickness) m Outer radius of raft m Inner radius of raft m Outer radius of ring wall m Inner radius of ring wall m Thickness of sand bitumen mix m 3. Analysis of gravity loads, horizontal loads (except seismic, wind load) Self weight of ring wall raft kN Moment exerted by self weight of ring raft about outer edge of raft kN‐m Self weight of ring wall kN Moment exerted by self weight of ring wall about outer edge of ring raft kN‐m Total structural steel weight of bottom plates kN Total structural steel weight of shell plates, appurtenances and staircase kN Total structural steel weight of roof plates and supporting structure kN Total structural steel weight of empty tank kN Total structural steel weight acting on ring wall footing kN (excluding weight of bottom plates inside ring wall footing) Moment exerted by total structural steel weight about outer edge of ring raft kN‐m Total weight of compacted sand acting on inner projection of raft kN Moment exerted by compacted sand weight about outer edge of ring raft kN‐m Total weight of ethanol acting on inner projection of raft in tank full condition kN Moment exerted by ethanol resting on inner projection of raft about outer edge of ring raft kN‐m (in tank full condition) Weight of backfilled earth kN on outer projection of ring raft kN Moment exerted by backfill about outer edge of ring raft kN‐m 30.000 4.000 8.000 8.000 16.700 116.739 0.350 0.782 1.850 0.550 2.000 0.650 0.800 2.000 2.650 5.000 3.000 4.275 3.725 0.050 816.400 4082.000 690.800 3454.000 63.765 73.575 68.670 206.010 188.606 943.030 520.522 2602.609 1022.672 5113.360 423.135 2115.677 Weight of bitumen on ring wall kN Moment exerted by bitumen carpet about outer edge of ring raft kN‐m Active earth pressure kN exerted on wall towards outside direction by compacted sand kN Moment exerted by this active earth pressure about TOC of ring raft kN‐m Passive earth pressure kN exerted on wall towards inside direction by backfilled earth kN per meter circumferential length Moment exerted by this passive earth pressure about TOC of ring raft kNm Surcharge ethanol pressure (tank full) at wall TOC level kN/sq.m Total udl force on wall due to ethanol surcharge outwards kN/m Moment exerted by ethanol surcharge udl about raft TOC kN‐m Surcharge pressure due to structural steel weight kN/sq.m at wall TOC Total udl force on wall due to structural steel surcharge outwards kN/m Moment exerted by structural steel udl about raft TOC kN‐m Surcharge pressure due to bitumen weight kN/sq.m at wall TOC Total udl force on the wall due to bitumen surcharge outwards kN/m Moment exerted by bitumen udl about raft TOC kN‐m 4. Impulsive seismic analysis when tank is full and empty (IS 1893 part 1: 2016, IS 1893 part 2: 2014, API 650: 2020) Zone factor for Rewari (IS 1893 part 1 2016, table 3, page 10). Rewari is in Zone IV. Importance factor I (IS 1893 part 1 2016, table 8/ clause 7.2.3, page 19) Mass density of ethanol N/cu.m H/D (H is the shell height, D is shell diameter) Coefficient Ci for H/D= 1.000 (API 650 2020, figure E.1, page E‐13) Thickness of shell plates tu m Elastic modulus of steel E N/sq.m Impulsive natural period Ti sec (API 650 2020, clause E.4.5.1‐1a, page E‐12) Sa/g in impulsive mode for time period= 0.007 sec (IS 1893 part 1 2016, clause 6.4.2, page 9) Impulsive response reduction factor Rwi (API 650 2020, table E.4, page E‐15) Design horizontal seismic coefficient in impulsive mode Ahi (IS 1893 part 2 2014, clause 4.5.2,page 7) Effective impulsive weight of ethanol in tank full condition kN (API 650 2020, E.6.1.1‐2, page E‐16) Total effective impulsive weight of tank in full condition kN Total effective impulsive weight of tank in empty condition kN Impulsive base shear in tank full condition Kn (API 650 2020, E.6.1‐2, page E‐16) Impulsive base shear in tank empty condition Kn (API 650 2020, E.6.1‐2, page E‐16) Height above base plates at which the center of action of slab overturning moment lies in impulsive mode m (API 650 2020, clause E.6.1.2.2‐2, page E‐18) Moment exerted at raft BOC by seismic force in impulsive mode in tank full condition kN‐m Moment exerted at raft BOC by seismic force in impulsive mode in tank empty condition kN‐m Moment exerted at raft BOC by total shell weight kN‐m Moment exerted at raft BOC by total roof weight kN‐m 5. Convective seismic analysis when tank is full and empty (IS 1893 part 1: 2016, IS 1893 part 2: 2014, API 650: 2020) D/H (D is shell diameter, H is shell height) Sloshing factor Ks (API 650 2020, figure EC.6, page EC‐7) Convective period Tc sec (API 650 2020, clause E.4.5.2‐a, page E‐13) Sa/g in convective mode for time period = 2.952 sec (IS 1893 part 1 2016, clause 6.4.2, page 9) Convective response reduction factor Rwc (API 650 2020, table E.4, page E‐15) Design horizontal seismic coefficient in convective mode Ahc (IS 1893 part 2 2014, clause 4.5.2,page 7) Effective convective weight of ethanol in tank full condition kN (API 650 2020, E.6.1.1‐3, page E17) Total effective convective weight of tank in full condition Kn Total effective convective weight of tank in empty condition Kn 15.198 75.988 11.250 7.500 39.168 15.667 66.800 44.205 88.411 14.911 9.867 19.735 1.100 0.728 1.456 0.240 1.250 8350.000 1.000 6.200 0.008 210000000000.000 0.007 2.500 4.000 0.094 2624.417 5296.482 2672.065 496.545 250.506 4.480 3565.194 1798.634 492.953 734.769 1.000 0.580 2.953 0.565 2.000 0.042 770.886 3442.951 2672.065 Convective base shear in tank full condition Kn (API 650 2020, E.6.1‐3, page E‐16) Convective base shear in tank empty condition Kn (API 650 2020, E.6.1‐3, page E‐16) Height above base plates at which the center of action of slab overturning moment lies in convective mode m (API 650 2020, clause E.6.1.2.2‐3, page E‐18) Moment exerted at raft BOC by seismic force in convective mode in tank full condition kN‐m Moment exerted at raft BOC by seismic force in convective mode in tank empty condition kN‐m 6. Vertical seismic analysis when tank is full and empty (IS 1893 part 1: 2016, IS 1893 part 2: 2014, API 650: 2020) Design vertical acceleration coefficient in impulsive mode (IS 1893 part 2 2014, clause 4.10.1,page 10) Vertical seismic force in impulsive mode in tank full condition, kN Vertical seismic force in impulsive mode in tank empty condition, kN Moment exerted by vertical seismic force in impulsive mode about outer edge of raft kN‐m in tank full condition Moment exerted by vertical seismic force in impulsive mode about outer edge of raft kN‐m in tank empty condition Design vertical acceleration coefficient in convective mode (IS 1893 part 2 2014, clause 4.10.1,page 10) Vertical seismic force in convective mode in tank full condition, kN Vertical seismic force in convective mode in tank empty condition, kN Moment exerted by vertical seismic force in convective mode about outer edge of raft kN‐m in tank full condition Moment exerted by vertical seismic force in convective mode about outer edge of raft kN‐m in tank empty condition Surcharge pressure in tank full condition due to vertical seismic force kN/sq.m Total udl force on wall due to vertical surcharge outwards kN/m Moment exerted at wall‐raft interface due to vertical surcharge kN‐m 7. Combined seismic analysis‐ impulsive, convective and vertical when tank is full and empty Combined base shear acting in tank full condition kN Combined overturning slab moment in tank full condition kN‐m (API 650 2020, E.6.1.5‐2, page E‐20) Combined base shear acting in tank empty condition kN Combined overturning slab moment in tank empty condition kN‐m (API 650 2020, E.6.1.5‐2, page E‐20) 8. Wind analysis (same for tank full and tank empty conditions, IS 875 part 3: 2015 ) Basic wind speed Vb m/s (annex A/clause 6.2, page 51) k1 (table 1/clause 6.3.1, page 7) k2 (table 2/clause 6.3.2.2, page 8) k3 (clause 6.3.3.1, page 8) k4 (clause 6.3.4, page 9) Design wind speed Vz m/s (clause 6.3, page 5) Design wind pressure Pz N/sq.m (clause 7.2, page 9) External pressure coefficient Cpe (table 5, page 13) Internal pressure coefficient Cpi (clause 7.3.2.1, page 11) Effective frontal area normal to wind force sq.m Wind load acting on shell kN (clause 7.3.1, page 10) Moment exerted by wind load about raft TOC kN‐m 9. Check for overturning of ring wall in tank full and empty conditions Overturning moment in tank full condition about outer raft edge kN‐m (only seismic, no wind) Sum of restoring moments in tank full condition about outer raft edge kN‐m Factor of safety against overturning when the tank is full of ethanol (only seismic, no wind) Overturning moment in tank full condition about outer raft edge kN‐m (only wind, no seismic) Factor of safety against overturning when the tank is full of ethanol (only wind, no seismic) Overturning moments in tank empty condition about outer raft edge kN‐m (only seismic, no wind) Sum of restoring moments in tank empty condition about outer raft edge kN‐m Factor of safety against overturning in tank empty condition (only seismic, no wind) Overturning moments in tank empty condition about outer raft edge kN‐m (only wind, no seismic) 145.895 113.229 6.033 880.128 683.065 0.063 331.030 15.657 1655.151 78.283 0.028 97.263 75.486 486.317 377.429 6.868 4.545 9.089 622.000 463.593 285.512 286.209 47.000 1.060 1.000 1.000 1.150 57.293 1969.493 ‐1.200 0.200 64.000 176.467 762.588 463.593 18310.675 39.497 762.588 24.011 286.209 13197.315 46.111 762.588 Factor of safety against overturning in tank empty condition (only wind, no seismic) 17.306 Inference: Since the factor of safety is greater than 1.550 for all tank full and tank empty conditions, the ring wall is safe against overturning. 10. Check for sliding of ring wall in tank full and empty conditions Total weight of foundation in tank full condition, excluding compacted sand and tank ethanol inside inner edge of footing kN (conservative 3662.135 weight estimate) Total weight of foundation in tank empty condition, excluding compacted sand and tank ethanol inside inner edge of footing kN (conservative 2639.463 weight estimate) Total sliding force in tank full condition kN (only seismic, no wind) 622.000 Friction resistance offered by ring foundation in tank full condition excluding compacted sand and ethanol enclosed by inner edge of footing kN 1249.704 (API 650 2020, clause E.7.6‐1, page E‐28) Factor of safety against sliding in tank full condition (only seismic, no wind) 2.009 Total sliding force in tank full condition kN (only wind, no seismic) 176.467 Factor of safety against sliding in tank full condition (only wind, no seismic) 7.082 Total sliding force in tank empty condition kN (only seismic, no wind) 285.512 Friction resistance offered by ring foundation in tank empty condition excluding compacted sand and ethanol enclosed by inner edge of footing 794.478 kN (API 650 2020, clause E.7.6‐1, page E‐28) Factor of safety against sliding in tank empty condition (only seismic, no wind) 2.783 Factor of safety against sliding in tank empty condition (only wind, no seismic) 4.502 Inference: Since the factor of safety is greater than 1.550 for all tank full and tank empty conditions, the ring wall is safe against sliding 11. Check for subsidence of ring wall in tank full and empty conditions Let the resultant force due to total gravity load and total horizontal force lie at a distance of x meters from the outer edge of the raft. x when tank is full m (only seismic, no wind) 4.873 Eccentricity of the resultant force from raft outer edge when tank is full e m (only seismic, no wind) 0.127 x when tank is full m (only wind, no seismic) 4.792 Eccentricity of the resultant force from raft outer edge when tank is full e m (only wind, no seismic) 0.208 x when tank is empty m (only seismic, no wind) 4.892 Eccentricity of the resultant force from raft outer edge when tank is empty e m (only seismic, no wind) 0.108 x when tank is empty m(only wind, no seismic) 4.711 Eccentricity of the resultant force from raft outer edge when tank is empty e m (only wind, no seismic) 0.289 Inference: Outer diameter of raft/3 = 10000/3 = 3334mm. The value of x is more than (outer diameter of raft/3) for both tank full and tank empty conditions. The resultant force shall be within a radial distance of (outer radius of raft)/3= 5000/3= 1666mm from tank center point (middle one‐third radial distance). In other words, the eccentricity shall be more than 5000‐ 1666=3334mm from the outer edge of raft. This condition is satisfied for all load cases in tank full and empty situations. Hence the ring wall foundation is safe against subsidence. 12. Required bearing capacity of subgrade after ground improvement for worst case‐ tank full and maximum eccentricity Total weight of foundation in tank full condition per meter circumferential length kN (conservative worst case estimate) 251.480 Maximum presure acting under heel in tank full condition kN/sq.m 234.725 Bearing capacity required after ground improvement (kN/sq.m) 234.725 Bearing capacity required after ground improvement (ton/sq.m) 24.000 13. Check for minimum pressure under heel for worst case‐ tank empty and maximum eccentricity Total weight in tank empty condition acting on 1 meter circumferential length of ring raft kN (conservative worst case estimate) 105.074 Minimum presure acting under toe in tank empty condition kN/sq.m 13.729 Inference: Since the minimum possible pressure under the toe is positive for all conditions, the ring wall is safe against tension or separation. 14. Ring wall vertical reinforcement for worst case (tank full) Impulsive base shear in tank full condition per meter circumferential length kN/m 19.767 Moment exerted by this impulsive base shear at wall‐raft interface kN‐m 141.927 Total shell weight per meter circumferential length kN/m 2.929 Moment exerted by this shell weight at wall‐raft interface kN‐m 19.624 Total roof weight per meter circumferential length kN/m 2.734 Moment exerted by this roof weight at wall‐raft interface kN‐m 29.250 Convective base shear in tank full condition per meter circumferential length kN/m 5.808 Moment exerted by this convective base shear at wall‐raft interface kN‐m 35.037 Vertical impulsive seismic force in tank full condition per meter circumferential length kN/m 17.571 Moment exerted by this vertical impulsive seismic force about raft outer edge kN‐m 87.853 Vertical convective seismic force in tank full condition per meter circumferential length kN/m 5.163 Moment exerted by this vertical convective seismic force about raft outer edge kN‐m 25.813 Moment exerted by combined seismic force (convective, impulsive, vertical) at wall‐raft interface kN‐m 18.839 Wind load acting per circumferential length of shell kN (clause 7.3.1, page 10) 14.050 Moment exerted by this wind load at wall‐raft interface kN‐m 85.002 Moment exerted by active earth pressure of compacted sand at wall‐raft interface kN‐m 7.500 Moment exerted by ethanol surcharge udl at wall‐raft interface kN‐m 88.411 Moment exerted by structural steel surcharge udl about raft TOC kN‐m 19.735 Moment exerted by bitumen surcharge udl about raft TOC kN‐m 1.456 Moment exerted by vertical seismic force surcharge udl about raft TOC kN‐m 9.089 Total moment acting on the wall‐raft interface kN‐m 211.192 Factored moment Mu acting on the wall‐raft interface kN‐m 316.789 Grade of concrete MPa 30.000 Yield strength of steel MPa 500.000 Effective depth of wall d (center to center of vertical reinforcement) mm 477.000 Mu/(b*d*d) Mpa, b is unit circumference of wall= 1000mm 1.392 Percentage of steel required (SP 16:1980, table 4, page 50) 0.341 Diameter of vertical bars used in ring wall mm 25.000 Spacing of vertical bars used mm 205.000 Number of vertical bars per face of ring wall 130.000 Total area of vertical bars provided per face of wall sq.mm 63781.250 Percentage of steel provided 0.532 Inference: Area of steel provided > Area of steel required for wall vertical bars. The value of Mu/(b*d*d) is less than the limiting value of 3.980 MPa for M30 concrete and Fe500 steel. The percentage of reinforcement adopted is less than the limiting value of 1.132 for M30 concrete and Fe 500 steel. Hence the section is under reinforced. The spacing of wall vertical reinforcement is less than the lesser value of 300mm and 3d. Shear force at wall‐raft interface because of combined seismic force per meter circumferential length (impulsive, convective and vertical) Kn 27.565 Shear force at wall‐raft interface because of wind load per meter circumferential length kN Shear force at wall‐raft interface because of compacted sand's earth pressure Kn Shear force at wall‐raft interface due to ethanol surcharge outwards kN Shear force at wall‐raft interface due to structural steel surcharge outwards kN Shear force at wall‐raft interface due to bitumen surcharge outwards kN Shear force at wall‐raft interface due to vertical seismic force surcharge outwards Kn Maximum shear force at wall‐raft interface kN Factored shear force at junction kN Shear stress at wall‐raft interface Mpa For percentage of provided reinforcement = 0.532, design shear stress in M30 concrete, MPa (IS 456:2000, Table 19, page 73) = Inference: Since nominal shear stress is less than design shear stress for M30 concrete, the ring wall section is safe in shear. 15. Ring wall circumferential reinforcement for hoop tension for worst case (tank full) Hoop tension udl per meter height because of compacted sand fill kN/m Total hoop tension because of compacted sand acting on ring wall per meter height Kn Total combined seismic force acting on ring wall kN Outward lateral pressure induced by this seismic load on ring wall kN/sq.m 14.050 11.250 88.411 19.735 1.456 9.089 157.506 236.259 0.495 0.511 192.589 192.589 622.000 13.295 Hoop stress because of combined seismic lateral pressure kN/sq.m (thick walled cylinder) 97.145 Total hoop tension because of combined seismic load acting on ring wall per meter height Kn 53.430 Total surcharge acting on the wall (ethanol, structural steel, bitumen, vertical seismic force) kN/sq.m 89.678 Total udl along height of wall because of total surcharge kN/m 59.345 Outward lateral pressure induced by total surcharge kN/sq.m 59.345 Hoop stress because of total surcharge acting on ring wall per meter height kN/sq.m 433.643 Total hoop tension because of all surcharges acting on ring wall per meter height Kn 238.504 Total hoop tension acting per meter height of the wall kN 484.522 Factored hoop tension acting per meter height of the wall kN 726.783 Allowable stress in Fe500 steel, Mpa (working stress for crack free design of wall) (IS 456:2000, note 1 below table 22, page 82) 275.000 Total area of steel required per meter height for hoop reinforcement sq.mm 2642.847 Total area of steel required per meter height per face for hoop reinforcement sq.mm 1321.423 Total area of steel required per face for entire 2 meters height of ring wall sq.mm 2642.847 Diameter of steel used for circumferential wall reinforcement mm 16.000 Center to center spacing of circumferential bars mm 150.000 Total number of circumferential bars per face of ring wall 15.000 Total area of steel provided as hoop reinforcement per face sq.mm 3014.400 Total area of steel provided as hoop reinforcement for both faces sq.mm 6028.800 Percentage of steel provided as circumferential reinforcement 0.746 Inference: Area of steel provided > Area of steel required for wall hoop bars. The percentage of reinforcement adopted is less than the limiting value of 1.132 for M30 concrete and Fe 500 steel. Hence the section is under reinforced. The spacing of wall hoop reinforcement is less than the lesser value of 300mm and 3d. 16. Heel reinforcement Weight of compacted sand backfill resting on heel per meter length kN 24.650 Moment exerted by compacted sand weight about heel edge of ring raft kN‐m 8.936 Weight of heel projection per meter length kN 11.781 Moment exerted by heel projection weight about heel edge kN‐m 4.271 Weight of pressure distribution rectangle per meter length kN ‐9.953 Moment exerted by pressure distribution rectangle about heel edge kN‐m ‐3.608 Weight of pressure distribution triangle per meter length kN ‐29.040 Moment exerted by pressure distribution triangle about heel edge kN‐m ‐14.036 Total moment at heel‐stem interface kN‐m ‐4.438 Factored moment Mu acting at heel‐stem interface kN‐m ‐6.657 Absolute value of Mu kN‐m 6.657 Effective depth of heel d (center to center of main reinforcement) mm 504.000 Mu/(b*d*d) Mpa, b is unit circumference of heel= 1000mm 0.026 Percentage of steel required (SP 16:1980, table 4, page 50) 0.070 Area of steel required per meter circumferential length of heel sq.mm 352.800 Total area of steel required per face of raft sq.mm 10916.182 Diameter of short raft bars used mm 16.000 Spacing of raft short bars provided mm 200.000 Number of short bars provided per face of raft 156.000 Area of steel provided per face of raft sq.mm 31349.760 Percentage of steel provided, considering both faces 0.660 Inference: Area of steel provided > Area of steel required for raft bars. The percentage of reinforcement adopted is less than the limiting value of 1.132 for M30 concrete and Fe 500 steel. Hence the section is under reinforced. The spacing of raft reinforcement is less than the lesser value of 300mm and 3d. Total area of distribution steel required per face of raft sq.mm 1560.000 Diameter of distribution bars used per face of raft mm 16.000 Spacing of distribution bars provided per face of raft mm 200.000 Number of distribution bars provided per face of raft 11.000 Area of distribution steel provided per face of raft sq.mm 2210.560 Inference: Area of steel provided > Area of steel required for raft distribution bars. Shear at stem‐heel junction kN ‐2.563 Absolute value of Mu kN 2.563 Shear stress at stem‐heel interface Mpa 0.005 Factored shear stress at junction kN 0.008 For percentage of steel=0.330 (per face of raft), design shear stress in M30 concrete MPa (IS 456:2000, table 19, page 73) 0.411 Inference: Since factored shear stress is less than design shear stress of concrete, the section is safe in shear at the wall‐heel junction 17. Toe reinforcement for worst case (tank full) Weight of toe slab per meter length kN 11.781 Moment exerted by toe projection weight about toe edge kN‐m ‐4.271 Weight of pressure distribution rectangle per meter length kN 9.953 Moment exerted by pressure distribution rectangle about toe edge kN‐m 3.608 Shorter side of pressure distribution trapezium kN/sq‐m 140.885 Longer side of pressure distribution trapezium kN/sq‐m 220.996 Height of pressure distribution trapezium m 0.725 Weight of pressure distribution trapezoid per meter length kN 131.182 Lever arm of pressure distribution trapezoid m 0.336 Moment exerted by pressure distribution trapezoid about toe edge kN‐m 44.044 Total moment at toe‐stem interface kN‐m 43.382 Factored moment Mu acting at toe‐stem interface kN‐m 65.073 Mu/(b*d*d) Mpa, b is unit circumference of toe= 1000mm 0.256 Percentage of steel required (SP 16:1980, table 4, page 50) 0.099 Area of steel required per meter circumferential length of toe sq.mm 643.500 Total area of steel required per face of raft sq.mm 19910.894 Diameter of short bars used per face of raft mm 16.000 Spacing of short bars provided per face of raft mm 200.000 Number of short bars provided per face of raft 156.000 Area of steel provided per face of raft sq.mm 31349.760 Percentage of steel provided, considering both faces 0.660 Inference: Area of steel provided > Area of steel required for raft bars. The percentage of reinforcement adopted is less than the limiting value of 1.132 for M30 concrete and Fe 500 steel. Hence the section is under reinforced. The spacing of raft reinforcement is less than the lesser value of 300mm and 3d. Total area of distribution steel required per face of raft sq.mm 1560.000 Diameter of distribution bars used per face of raft mm 16.000 Spacing of distribution bars provided per face of raft mm 200.000 Number of distribution bars provided per face of raft 11.000 Area of distribution steel provided per face of raft sq.mm 2210.560 Inference: Area of steel provided > Area of steel required for raft distribution bars. Distance between critical shear section and toe‐raft junction mm 0.404 Height of pressure distribution diagram at this critical section kN/sq‐m 185.526 Net shear force at the section kN 62.234 Shear stress at critical section of toe Mpa 0.123 Factored shear stress at critical section Mpa 0.185 Percentage of steel provided per raft face 0.330 For percentage of steel=0.330 (per face of raft), design shear stress in M30 concrete MPa (IS 456:2000, table 19, page 73) 0.411 Inference: Since factored shear stress is less than design shear stress of concrete, the section is safe in shear at the critical toe junction.
