Isolated Footing Design (IS 456-2000) - Bentley
Isolated Footing Design Page 1 of 42 Isolated Footing Design (IS 456-2000) Design For Isolated Footing 1 Design For Isolated Footing 2 Design For Isolated Footing 7 Design For Isolated Footing 8 Footing No. - Group ID - Length 1 1 1.150m Footing No. Foundation Geometry Width 1.150m Footing Reinforcement Thickness 0.230m Pedestal Reinforcement - Bottom Reinforcement(Mz) Bottom Reinforcement(Mx) Top Reinforcement(Mz) Top Reinforcement(Mx) Main Steel Trans Steel 1 Ø8 @ 140 mm c/c Ø8 @ 140 mm c/c N/A N/A N/A N/A Foundation Geometry Width Footing No. - Group ID - Length 2 2 1.150m Footing No. 1.150m Footing Reinforcement Thickness 0.230m Pedestal Reinforcement - Bottom Reinforcement(Mz) Bottom Reinforcement(Mx) Top Reinforcement(Mz) Top Reinforcement(Mx) Main Steel Trans Steel 2 Ø8 @ 140 mm c/c Ø8 @ 140 mm c/c N/A N/A N/A N/A Foundation Geometry Width Footing No. - Group ID - Length 7 3 1.150m Footing No. - Bottom Reinforcement(Mz) 7 Ø8 @ 140 mm c/c Footing Reinforcement Bottom Reinforcement(Mx) Top Reinforcement(Mz) Ø8 @ 140 mm c/c Trans Steel N/A N/A N/A Foundation Geometry Width 8 4 1.150m 8 Ø8 @ 140 mm c/c Footing Reinforcement Bottom Reinforcement(Mx) Top Reinforcement(Mz) Ø8 @ 140 mm c/c Pedestal Reinforcement N/A Length Bottom Reinforcement(Mz) 0.230m Main Steel Group ID - - Thickness Top Reinforcement(Mx) Footing No. - Footing No. 1.150m N/A 1.150m Thickness 0.230m Pedestal Reinforcement Top Reinforcement(Mx) Main Steel Trans Steel N/A N/A N/A Isolated Footing 1 ooting.xml 22/08/2013
Isolated Footing Design Page 2 of 42 Input Values Footing Geomtery Design Type : Calculate Dimension Footing Thickness (Ft) : 230.000mm Footing Length - X (Fl) : 900.000mm Footing Width - Z (Fw) : 900.000mm Eccentricity along X (Oxd) : 0.000mm Eccentricity along Z (Ozd) : 0.000mm Column Dimensions Column Shape : Rectangular Column Length - X (Pl) : 0.230m Column Width - Z (Pw) : 0.230m Pedestal Include Pedestal? No Pedestal Shape : N/A Pedestal Height (Ph) : N/A Pedestal Length - X (Pl) : N/A Pedestal Width - Z (Pw) : N/A ooting.xml 22/08/2013
Isolated Footing Design Page 3 of 42 Design Parameters Concrete and Rebar Properties Unit Weight of Concrete : 25.000kN/m3 Strength of Concrete : 20.000N/mm2 Yield Strength of Steel : 415.000N/mm2 Minimum Bar Size : Ø8 Maximum Bar Size : Ø16 Pedestal Minimum Bar Size : Ø12 Pedestal Maximum Bar Size : Ø32 Minimum Bar Spacing : 50.000mm Maximum Bar Spacing : 200.000mm Pedestal Clear Cover (P, CL) : 50.000mm Footing Clear Cover (F, CL) : 75.000mm Soil Properties Soil Type : Drained Unit Weight : 18.000kN/m3 Soil Bearing Capacity : 200.000kN/m2 Soil Bearing Capacity Type: Gross Bearing Capacity Soil Surcharge : 0.000kN/m2 Depth of Soil above Footing : 2800.000mm Cohesion : 0.000kN/m2 Min Percentage of Slab in Contact: 0.000 Sliding and Overturning Coefficient of Friction : 0.500 Factor of Safety Against Sliding : 1.500 Factor of Safety Against Overturning : 1.500 Global Settings Top Reinforcement Option : Calculate only when foundation is subjected to uplift forces Concrete Design Option : Gross Pressure ---- Design Calculations Load Combination/s- Service Stress Level Load Combination Number Load Combination Title 1 2 101 1.000 x DL 102 1.000 x DL 1.000 x LL Load Combination/s- Strength Level Load Combination Number Load Combination Title 1 2 201 1.500 x DL ooting.xml 22/08/2013
Isolated Footing Design Page 4 of 42 202 1.500 x DL 1.500 x LL Applied Loads - Service Stress Level 1 2 101 102 Axial (kN) 86.584 18.000 86.584 104.584 1 2 201 202 Axial (kN) 86.584 18.000 129.876 156.876 LC Shear X (kN) -0.716 -0.204 -0.716 -0.920 Shear Z (kN) -0.716 -0.204 -0.716 -0.920 Moment X (kNm) 0.000 0.000 0.000 0.000 Moment Z (kNm) 0.000 0.000 0.000 0.000 Applied Loads - Strength Level LC Shear X (kN) -0.716 -0.204 -1.074 -1.380 Shear Z (kN) -0.716 -0.204 -1.074 -1.380 Moment X (kNm) 0.000 0.000 0.000 0.000 Moment Z (kNm) 0.000 0.000 0.000 0.000 ---Footing Size Initial Length (Lo) 0.900m Initial Width (Wo) 0.900m Uplift force due to buoyancy 0.000kN Effect due to adhesion 0.000kN Area from initial length and width, Ao L X W 0.810m2 o o 2 Min. area required from bearing pressure, Amin P / q max 0.721m Note: Amin is an initial estimation. P Critical Factored Axial Load(without self weight/buoyancy/soil). qmax Respective Factored Bearing Capacity. Final Footing Size Length (L2) 1.150 m Governing Load Case : #1 Width (W2) 1.150 m Governing Load Case : #1 Depth (D2) 0.230 m Governing Load Case : #1 Area (A2) 1.323 m2 Depth is governed by Ultimate Load Case (Service check is performed with footing thickness requirements from concrete check) Final Soil Height 2.570 m ---Pressures at Four Corner ooting.xml 22/08/2013
Isolated Footing Design Page 5 of 42 Area of footing in uplift (Au) Pressure at corner 1 (q1) Pressure at corner 2 (q2) Pressure at corner 3 (q3) Pressure at corner 4 (q4) (kN/m2) (kN/m2) (kN/m2) (kN/m2) 102 130.9101 129.2403 127.5704 129.2403 0.000 102 130.9101 129.2403 127.5704 129.2403 0.000 102 130.9101 129.2403 127.5704 129.2403 0.000 102 130.9101 129.2403 127.5704 129.2403 0.000 Load Case (m2) If Au is zero, there is no uplift and no pressure adjustment is necessary. Otherwise, to account for uplift, areas of negative pressure will be set to zero and the pressure will be redistributed to remaining corners. Summary of adjusted Pressures at Four Corner Load Case Pressure at corner 1 (q1) Pressure at corner 2 (q2) Pressure at corner 3 (q3) Pressure at corner 4 (q4) (kN/m2) (kN/m2) (kN/m2) (kN/m2) 102 130.9101 129.2403 127.5704 129.2403 102 130.9101 129.2403 127.5704 129.2403 102 130.9101 129.2403 127.5704 129.2403 102 130.9101 129.2403 127.5704 129.2403 Details of Out-of-Contact Area (If Any) Governing load case N/A Plan area of footing 1.323sq.m Area not in contact with soil 0.000sq.m % of total area not in contact 0.000% ---Check For Stability Against Overturning And Sliding - Factor of safety against sliding Factor of safety against overturning Load Case No. Along XDirection Along ZDirection Resultant W.R.T. XDirection W.R.T. ZDirection 1 106.757 106.757 75.489 533.785 533.785 2 206.747 206.747 146.192 1033.733 1033.733 101 106.757 106.757 75.489 533.785 533.785 102 92.875 92.875 65.672 464.373 464.373 Critical Load Case And The Governing Factor Of Safety For Overturning and Sliding X Direction Critical Load Case for Sliding along X-Direction : 102 Governing Disturbing Force : -0.920kN ooting.xml 22/08/2013
Isolated Footing Design Page 6 of 42 Governing Restoring Force : 85.460kN Minimum Sliding Ratio for the Critical Load Case : 92.875 Critical Load Case for Overturning w.r.t. X-Direction : 102 Governing Overturning Moment : -0.212kNm Governing Resisting Moment : 98.277kNm Minimum Overturning Ratio for the Critical Load Case : 464.373 Critical Load Case And The Governing Factor Of Safety For Overturning and Sliding Z Direction Critical Load Case for Sliding along Z-Direction : 102 Governing Disturbing Force : -0.920kN Governing Restoring Force : 85.460kN Minimum Sliding Ratio for the Critical Load Case : 92.875 Critical Load Case for Overturning w.r.t. Z-Direction : 102 Governing Overturning Moment : 0.212kNm Governing Resisting Moment : 98.277kNm Minimum Overturning Ratio for the Critical Load Case : 464.373 Critical Load Case And The Governing Factor Of Safety For Sliding Along Resultant Direction Critical Load Case for Sliding along Resultant 102 Direction : Governing Disturbing Force : 1.301kN Governing Restoring Force : 85.460kN Minimum Sliding Ratio for the Critical Load Case : 65.672 ---- Compression Development Length Check Development length skipped as column reinforcement is not specified in input (Column Dimnesion Task Pane) Top Reinforcement Design Requirement Top Reinforcement needs to be provided because of resultant negative pressure coming from net pressure calculations for bending. Please check 'Always Calculate Top Reinforcement Option' from Global Settings Moment Calculation Check Trial Depth against moment (w.r.t. Z Axis) Critical Load Case #202 Effective Depth 0.151m Governing moment (Mu) 20.647kNm As Per IS 456 2000 ANNEX G G-1.1C 0.479107 Limiting Factor1 (Kumax) Limiting Factor2 (Rumax) Limit Moment Of Resistance (Mumax) 2755.432917kN/m2 72.249306kNm Mu Mumax hence, safe Check Trial Depth against moment (w.r.t. X Axis) Critical Load Case #202 ooting.xml 22/08/2013
Isolated Footing Design Page 7 of 42 0.151m Effective Depth Governing moment (Mu) 20.647kNm As Per IS 456 2000 ANNEX G G-1.1C Limiting Factor1 (Kumax) 0.479107 Limiting Factor2 (Rumax) 2755.432917kN/m2 Limit Moment Of Resistance (Mumax) 72.249306kNm Mu Mumax hence, safe ---- Shear Calculation Check Trial Depth for one way shear (Along X Axis) (Shear Plane Parallel to X Axis) Critical Load Case # 201 DX 0.309m Shear Force(S) 52.975kN Shear Stress(Tv) 305.066010kN/m2 Percentage Of Steel(Pt) 0.1999 As Per IS 456 2000 Clause 40 Table 19 Shear Strength Of Concrete(Tc) 326.161kN/m2 Tv Tc hence, safe Check Trial Depth for one way shear (Along Z Axis) (Shear Plane Parallel to Z Axis) ooting.xml 22/08/2013
Isolated Footing Design Page 8 of 42 Critical Load Case # 201 DZ 0.309m Shear Force(S) 52.975kN Shear Stress(Tv) 305.066009kN/m2 Percentage Of Steel(Pt) 0.1999 As Per IS 456 2000 Clause 40 Table 19 Shear Strength Of Concrete(Tc) 326.161kN/m2 Tv Tc hence, safe Check Trial Depth for two way shear Critical Load Case #202 Shear Force(S) 191.859kN Shear Stress(Tv) 833.722kN/m2 As Per IS 456 2000 Clause 31.6.3.1 Ks Shear Strength(Tc) 1.000 1118.0340kN/m2 Ks x Tc 1118.0340kN/m2 Tv Ks x Tc hence, safe ---- Reinforcement Calculation ooting.xml 22/08/2013
Isolated Footing Design Page 9 of 42 Calculation of Maximum Bar Size Along X Axis Bar diameter corresponding to max bar size (db) 8mm As Per IS 456 2000 Clause 26.2.1 Development Length(ld) Allowable Length(ldb) 0.360m 0.385m ldb ld hence, safe Along Z Axis Bar diameter corresponding to max bar size(db) 8mm As Per IS 456 2000 Clause 26.2.1 Development Length(ld) Allowable Length(ldb) 0.360m 0.385m ldb ld hence, safe Bottom Reinforcement Design Along X Axis For moment w.r.t. X Axis (Mz) As Per IS 456 2000 Clause 26.5.2.1 Critical Load Case #202 Minimum Area of Steel (Astmin) 317.400mm2 Calculated Area of Steel (Ast) 397.611mm2 Provided Area of Steel (Ast,Provided) 397.611mm2 Astmin Ast,Provided Steel area is accepted Selected bar Size (db) Ø8 Minimum spacing allowed (Smin) 48.000mm Selected spacing (S) 141.714mm ooting.xml 22/08/2013
Isolated Footing Design Page 10 of 42 Smin S Smax and selected bar size selected maximum bar size. The reinforcement is accepted. Based on spacing reinforcement increment; provided reinforcement is Ø8 @ 140.000mm o.c. Bottom Reinforcement Design Along Z Axis For moment w.r.t. Z Axis (Mx) As Per IS 456 2000 Clause 26.5.2.1 Critical Load Case #202 Minimum Area of Steel (Astmin) 317.400mm2 Calculated Area of Steel (Ast) 397.611mm2 Provided Area of Steel (Ast,Provided) 397.611mm2 Astmin Ast,Provided Steel area is accepted Selected bar Size (db) Ø8 Minimum spacing allowed (Smin) 50.000mm Selected spacing (S) 141.714mm Smin S Smax and selected bar size selected maximum bar size. The reinforcement is accepted. Based on spacing reinforcement increment; provided reinforcement is Ø8 @ 140.000mm o.c. Crack Width Calculation (for Mz) Modulus of Elasticity of Concrete(Ec) 22360679.775kN/m2 Modulus of Elasticity of Steel(Es) 200000000.000kN/m2 Depth of Neutral Axis(Xu) 0.072m Clause No. 6.2.3.1 Annexure F Annexure G, Clause No. G-1.1.a Effective MOI(Ieff) 0.000m4 Average Steel Strain at Considered Level(Ɛm) 20.945 X 10-5 Distance from Nearest Tension Rod (acr) 0.106m ooting.xml 22/08/2013
Isolated Footing Design Page 11 of 42 Crack Width (Wcr) 0.048mm Annexure F From IS 456-2000 Clause No. 35.3.2 Crack Width calculated at critical tension face(bottom face) is less than 0.2 mm.Hence OK. Crack Width Calculation (for Mx) Modulus of Elasticity of Concrete(Ec) 22360679.775kN/m2 Modulus of Elasticity of Steel(Es) 200000000.000kN/m2 Depth of Neutral Axis(Xu) 0.072m Clause No. 6.2.3.1 Annexure F Annexure G, Clause No. G-1.1.a Effective MOI(Ieff) 0.000m4 Average Steel Strain at Considered Level(Ɛm) 20.945 X 10-5 Distance from Nearest Tension Rod (acr) 0.106m Crack Width (Wcr) 0.048mm Annexure F From IS 456-2000 Clause No. 35.3.2 Crack Width calculated at critical tension face(bottom face) is less than 0.2 mm.Hence OK. ---- ooting.xml 22/08/2013
Isolated Footing Design Page 12 of 42 Isolated Footing 2 Input Values Footing Geomtery Design Type : Calculate Dimension Footing Thickness (Ft) : 230.000mm Footing Length - X (Fl) : 900.000mm Footing Width - Z (Fw) : 900.000mm Eccentricity along X (Oxd) : 0.000mm Eccentricity along Z (Ozd) : 0.000mm Column Dimensions Column Shape : Rectangular Column Length - X (Pl) : 0.230m Column Width - Z (Pw) : 0.230m Pedestal Include Pedestal? No Pedestal Shape : N/A Pedestal Height (Ph) : N/A Pedestal Length - X (Pl) : N/A ooting.xml 22/08/2013
Footing No. Footing Reinforcement Pedestal Reinforcement - Bottom Reinforcement(M z) x Top Reinforcement(M z x Main Steel Trans Steel 2 Ø8 @ 140 mm c/c Ø8 @ 140 mm c/c N/A N/A N/A N/A Footing No. Group ID Foundation Geometry - - Length Width Thickness 7 3 1.150m 1.150m 0.230m Footing No. Footing Reinforcement Pedestal Reinforcement
1 area of column in spread footing design A 2 projected bearing area of column load in spread footing design b rectangular column dimension in concrete footing design width, often cross-sectional b f width of the flange of a steel or cross section b o perimeter length for two-way shear in concrete footing design B spread footing .
Foundation or Footing Theories and Design: Part 2 Isolated Foundation or Footing transmit column load to the underlying soil. Figure: Tributary area for columns shown in shades/colors . Base Area of Footing Calculation: Weight of surcharge, soil plus concrete depth for footing (135pcf 5ft/1000) 0.675 ksf .
2.0 FOOTING GEOMETRY Wind turbine foundations are generally octagonal in shape. The diameter of the footing may vary anywhere from 50ft to 65ft with an average depth of 4 to 6 feet. An 8ft to 9ft pedestal (includes the height of the footing) of 18ft to 20ft diameter is provided. Figure 2 shows the plan view and section of the octagonal footing.
Use the deck guide that is included in this packet to assist you. Footing diagram: Footing depth below grade, thickness of footing, width of footing. Ledger Connection: Size of ledger board, fasteners being used, spacing of fasteners Deck posts: Post size, post height, connection to both footing and the deck beam.
FOOTING ID EXCAVATION SIZE [Lx' X Ly'] FOOTING SIZE [Lx X Ly] FOOTING THICKNESS DMax DMin REINFORCEMENT DETAILS Along X,Sx Along Y,Sy . SECTION A-A TYPICAL FOOTING A A GL Plinth Beam Column Bars Ld Well compacted earth Column Footing P.C.C 150 Dmin Dmax Sx Sy Upto hard strata 200 300-4 - Y16Y8@ 150/ 200 C/C 200 400-8 - Y16 Y8@ 150/-2 - Y12 .
Minimum Bar Size : 16 mm Maximum Bar Size : 25 mm Top Footing Minimum Bar Size : 16 mm Top Footing Maximum Bar Size : 25 mm Pedestal Minimum Bar Size : 16 mm Pedestal Maximum Bar Size : 25 mm Minimum Bar Spacing : 100.00mm Maximum Bar Spacing : 250.00mm Pedestal Clear Cover (P, CL) : 50.00mm Bottom Footing Clear Cover (F, CL) : 50.00mm Soil .
perform the reliability analysis of an isolated footing subjected to an axial load and the footing subjected to uniaxial moment,2) to find the variation of reliability index with load factor for each case, 3) to find the critical modes of failure a given load factorfor and 4) to find how reliability is affected by the age of the footing.
Archaeological Investigations and Recording 1994-2011 by David James Etheridge with scientific analysis by Dr David Dungworth Avon Archaeological Unit Limited Avondale Business Centre, Woodland Way, Kingswood, Bristol, BS15 1AW Bristol 2012 Illustration taken from the ‘Annales des Mines” Vol 10, dated 1825 . William Champion’s Warmley Brass and Zinc works, Warmley, South Gloucestershire .
