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Analyses and Ddesign of a Two Storied RC Building

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Analyses and Design of a Two-Storied RC Building

Analyses and Design of a Two-Storied RC Building

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  • 1. 1 | P a g e Civil & Environmental Engineering Department First semester -Term (131) CE 315 – Reinforced Concrete Term project Analyses and Design of a Two-Storied RC Building Instructors: Dr.Mohammed Baluch Dr.Mohammed Al-Osta Prepped by: Mohammed Jamal Sandougah ID# 200816060 Email: eng-kovo@hotmail.com
  • 2. 2 | P a g e Table of Contents 1. Introduction...........................................................................................................................................4 2. Project Objectives and scope of work...................................................................................................4 2.1. Description of Structure................................................................................................................5 2.2. Loads Calculation .........................................................................................................................7 2.2.1. Slab Loads.............................................................................................................................7 2.3. Building Geometry......................................................................................................................11 2.3.1. Modeling Stages..................................................................................................................11 2.3.2. Normal Structure.................................................................................................................11 2.3.3. Full Structure Modeling......................................................................................................14 2.4. Loads Assigned...........................................................................................................................15 2.5. Ribbed Slab Design.....................................................................................................................17 2.6. Beam Design...............................................................................................................................20 2.7. Column Design ...........................................................................................................................25 2.8. Foundation Design......................................................................................................................28 2.8.1. Procedure ............................................................................................................................28 2.8.2. Results.................................................................................................................................30 Conclusion ..................................................................................................................................................67 References...................................................................................................................................................68
  • 3. 3 | P a g e List of Figures Figure 2-1: Side View of the Building ..........................................................................................................5 Figure 2-2: Top View of the Building ..........................................................................................................6 Figure 2-3: Top View of the Building with Direction of Load.....................................................................7 Figure 2-4: Minimum Thickness for One-Way Solid and Ribbed Slabs......................................................8 Figure 2-5: Block Dimensions......................................................................................................................9 Figure 2-6: Ribbed Slab Dimensions ......................................................................................................10 Figure 2-7-1: Normal Structure (Front view) .............................................................................................11 Figure 2-7-2: Normal Structure (Side view)...............................................................................................12 Figure 2-8: Normal Structure (Top view)...................................................................................................13 Figure 2-9: Full Structure (3D Model).......................................................................................................12 Figure 2-10: Load on Grade Beams............................................................................................................13 Figure 2-11: Load on Parapet......................................................................................................................16 Figure 2-12: ACI Coefficients Conditions..................................................................................................17 Figure 2-13 : ACI Moment Coefficients (1)...............................................................................................18 Figure 2-14: ACI Moment Coefficients (2) ................................................................................................19 Figure 2-16: Critical Beam .........................................................................................................................20 Figure 2-17: Moment diagrom of beam#200..............................................................................................21 Figure 2-18: Steel arrangement of beam#200 (1) .......................................................................................21 Figure 2-19: Steel arrangement of beam#200 (2) .......................................................................................22 Figure 2-20: Shear Diagram for beam #200 ...............................................................................................23 Figure 2-21: Specifications of shear reinforcement of beam #200.............................................................24 Figure 2-22: Critical Column #127.............................................................................................................25 Figure 2-23: Output of column#127 ...........................................................................................................26 Figure 2-24: Footings distribution of Solid Slab Structure.........................................................................28 Figure 2-25: Concrete and Rebar Parameters .............................................................................................28 Figure 2-26: Cover and soil parameters......................................................................................................29 Figure 2-27: Footing geometry parameters.................................................................................................29 Figure 2-28: Typical elevation section of footing.......................................................................................30 Figure 2-29: Typical plan section of footing ..............................................................................................30
  • 4. 4 | P a g e 1. Introduction The design of the Two-story reinforced concrete structure entailed a number of steps and calculations. Each section listed below describes one step in the process of the design. Attached to the end of this report are sample hand calculations for each step in the design process. 2. Project Objectives and scope of work The main objectives revolved around the application of the theoretical background in reinforced concrete design courses to design a full structure instead of elements (beam, column, foundation and slab). Another objective of this project is to learn how to utilize the AutoCAD drawing software and the (STAAD.Pro) software tools in the best manner which would be time saving and practical in modeling, analyzing and designing the structure. Moreover, the project would help the group in interpreting the architectural drawings of the building which would be useful in future careers. On the managerial side, the group will conduct cost estimations and comparisons study for all alternatives which would help to improve the decision-making process and the quantity surveying skills. In addition, the project will help the group in improving time-management skills.
  • 5. 5 | P a g e 2.1. Description of Structure Building comprises of two story reinforced concrete structure. Basic building dimensions are as follows:  Building footprint: 13.5 m x 13.5 m.  Building height: Building height: 9.6 m. STADD side and top view drawings of the Building are shown in Figure and Figure 2-2. Figure 2-1: Said View
  • 6. 6 | P a g e Figure 2-2: Top View
  • 7. 7 | P a g e 2.2. Loads Calculation 2.2.1. Slab Loads a) Slab self weight Since the ratio of long edge to the short edge of slab = 𝟓 𝟓 = 𝟏 𝐚𝐥𝐬𝐨 𝟑.𝟓 𝟓 = 0.7  the load will transfer in the short direction as shown in Figure 2-3 and the design will assumed as one way solid slab and the hidden square as flour slab. Figure 2-3: Top View of the Building with Direction of Load UP
  • 8. 8 | P a g e Minimum slab depth: Following ACI-318-08 the minimum thickness for one-way solid slabs as shown in Figure 2-4 is 𝑙 24 for one end continuous and 𝑙 28 for both ends continuous. Figure 2-4: Minimum Thickness for One-Way Solid and Ribbed Slabs
  • 9. 9 | P a g e One end continuous 𝑙 24 = 5000 24 = 208.33 𝑚𝑚 Both ends continuous 𝑙 28 = 5000 28 = 178.57 𝑚𝑚 Weight of Block: No. of rib/m = 1 0.5 = 2 ribs No. of blocks/𝑚2 = 2 × 5 = 10 The weight of blocks in one meter square of ribbed slab = (Number of blocks) × (weight of one block) × (9.81)  Weight of blocks/𝑚2 = 10 × 12 × 9.81 1000 = 1.2 kN 𝑚2 Weight of ribs:  Each one meter of ribbed slab has two ribs as shown in Figure 2-6.  Weigh of 𝑟𝑖𝑏 = (width(b) × depth(d) × number of ribs) × (density of concrete) × (length)  Weight of ribs/𝑚2 = 2 × 0.1 × 0.2 × 25 = 1 kN 𝑚2 Figure 2-5: Block Dimensions
  • 10. 10 | P a g e Weight of top slab (t): Top slab weight = (minimum thickness – depth of rib (d)) × (density of concrete) × (length)  Weight of toping slab/m2 = 0.07 × 25 = 1.75 kN 𝑚2 Self weight of the ribbed slab: Self weight = (Weight of Block) + ( weight of rips) + ( Top mat weight)  Self Weight of ribbed slab = 1 + 1.2 + 1.75 = 3.95 kN 𝑚2 Figure 2-6: Ribbed Slab Dimensions
  • 11. 11 | P a g e 2.3. Building Geometry According to the Architectural drawings, the building is mainly composed of a 13.5 m X 13.5 m rooms with main beams spanning over 5, 3.5 and 3 meters with a center-to-center of column spacing of 5 and 3.5 meters. In addition, the building includes a rectangular bathroom with a thickness of 0.15 meters and with area of10.5 𝑚2. 2.3.1. Modeling Stages 1. Draw the normal structure using STAAD.Pro software 2. Define section properties of the structure (columns, beams and slab) 2.3.2. Normal Structure Front view dimensions of the two structures are shown in Figure 2-7-1. Figure 2-7-1: Normal Structure (Front view)
  • 12. 12 | P a g e Side view dimensions of the two structures are shown in Figure 2-7-2. Figure 2-7-2: Normal Structure (Side view)
  • 13. 13 | P a g e Top view dimensions are shown in Figure 2-8 . Figure 2-8: Normal Structure (Top view)
  • 14. 14 | P a g e 2.3.3. Full Structure Modeling 3D of the structure is shown in Figure 2-9. Figure 2-9: Full Structure (3D Model)
  • 15. 15 | P a g e 2.4. Loads Assigned Dead load on grade beam is 17.375 𝐾𝑁 𝑚 as shown in Figure 2-10. Figure 2-10: Load on Grade Beams
  • 16. 16 | P a g e Dead load on parapet is 12.2 𝐾𝑁 𝑚 as shown in Figure 2-11. Figure 2-11: Load on Parapet
  • 17. 17 | P a g e 2.5. Ribbed Slab Design Using ACI-318-08 chapter 8.3.3, Check the ACI limits which is shown in Figure 2-12. Figure 2-12: ACI Coefficients Conditions All conditions are satisfied.
  • 18. 18 | P a g e Figure 2-13: ACI Moment Coefficients (1)
  • 19. 19 | P a g e − 𝑊𝑢 𝑙𝑛2 24 + 𝑊𝑢 𝑙𝑛2 14 − 𝑊𝑢 𝑙𝑛2 10 − 𝑊𝑢 𝑙𝑛2 11 + 𝑊𝑢 𝑙𝑛2 16 − 𝑊𝑢 𝑙𝑛2 11 Figure 2-15: ACI Moment Coefficients (2) 𝑊𝑢 = 1.2(𝐷𝐿) + 1.6(𝐿𝐿) 𝑊𝑢 = 1.2(6.95) + 1.6(2.5) = 12.34 𝐾𝑁 𝑚 Apply moment coefficients which are shown in Figure 2-15: Equations used for calculations [1]: 1) 𝑀 𝑢 = 𝑚𝑜𝑚𝑒𝑛𝑡 𝑓𝑎𝑐𝑡𝑜𝑟 × 𝑊𝑢 × 𝑙 𝑛 2 2) 𝑅 𝑛 = 𝑀 𝑢 ∅𝑏𝑑2 3) 𝑚 = 𝑓𝑦 0.85𝑓′ 𝑐 4) 𝜌 = 1 𝑚 (1 − √1 − 2𝑚𝑅 𝑛 𝑓𝑦 ) 5) 𝜌min = 3 ×√𝑓𝑐′ 𝑓𝑦 but not less than 200 𝑓𝑦 6) 𝐴 𝑠 = 𝜌𝑏𝑑 𝑊𝑛 12.34 KN/m 𝑏 0.3048 m 𝑙 𝑛 5,3.5 m 𝑑 0.27 m 𝑓′ 𝑐 40 MPa 𝑓𝑦 420 MPa 𝑀 𝑢 -12.85 22.035 -30.85 -13.75 9.45 KN-m 𝑅 𝑛 -642.567 1101.864 -1542.65982 -687.571 472.5489 KN/m2 𝑚 12.35294 12.35294 12.35294 12.35294 12.35294 - 𝜌 0.001546 0.002667 0.003760 0.0016539 0.001133 - 𝜌 𝑚𝑖𝑛 0.00142857 0.00142857 0.00142857 0.00142857 0.00142857 - 𝐴 𝑠 127.229616 219.5190 309.4606 136.1094 117.5656 𝑚𝑚2 Bar #4 1 2 3 2 1 5.0 m 3.5 m
  • 20. 20 | P a g e 2.6. Beam Design Critical beam found to be beam # 200 as shown in Figure 2-16. Figure 2-16: Critical Beam Checking the design of beam # 200 For main re-bars Take cover = 0.04 𝑚 , ℎ = 0.5 𝑚 , 𝑏 = 0.2 𝑚 , 𝑑 = 0.46 𝑚
  • 21. 21 | P a g e From STAAD.pro analysis, max (-ve) moment 𝑀 𝑢 = −33.6𝐾𝑁. 𝑚 , 𝐴 𝑠 = 3 × 𝜋 4 × 122 = 339.3 𝑚𝑚2 Max (+ve) moment 𝑀 𝑢 = 10.6 𝐾𝑁. 𝑚 , 𝐴 𝑠 = 3 × 𝜋 4 × 122 = 339.3 𝑚𝑚2 As Shown in Figure . Figure 2-17: Moment diagram of beam #200 Moment diagram of beam #200 Figure 2-18: Steel arrangement of beam#200 (1)
  • 22. 22 | P a g e Figure 2-19: Steel arrangement of beam#200 (2) Calculating moment capacity of the beam in compression and tension, then check it with the applied moments. Equations used [1] : 1) 𝑀 𝑛 = 𝐴 𝑠 𝑓𝑦 (𝑑 − 𝑎 2 ) 2) 𝑎 = 𝐴 𝑠 𝑓𝑦 0.85𝑓𝑐 𝑏 𝑀 𝑛− = 𝐴 𝑠 𝑓𝑦 (𝑑 − 𝑎 2 ) , 𝑎 = 𝐴 𝑠 𝑓𝑦 0.85𝑓𝑐 𝑏 = 339.3×420 0.85×40×200 = 20.96 𝑚𝑚  𝑀 𝑛− = 339.3 × 420 (460 − 20.96 2 ) × 1 1000 𝑚𝑚 × 1 1000 𝑁 = 64.059 𝐾𝑁. 𝑚 𝑀 𝑛+ = 𝐴 𝑠 𝑓𝑦 (𝑑 − 𝑎 2 ) , 𝑎 = 𝐴 𝑠 𝑓𝑦 0.85𝑓𝑐 𝑏 = 339.3×420 0.85×40×200 = 20.96 𝑚𝑚  𝑀 𝑛+ = 339.3 × 420 (460 − 20.96 2 ) × 1 1000 𝑚𝑚 × 1 1000 𝑁 = 64.059 𝐾𝑁. 𝑚
  • 23. 23 | P a g e Check (-ve) moment: ∅𝑀 𝑛− = 0.9(64.059 ) = 57.65 > 33.6 𝐾𝑁. 𝑚  OK Check (+ve) moment: ∅𝑀 𝑛+ = 0.9(64.059 ) = 57.65 > 10.6 𝐾𝑁. 𝑚  OK For Stirrups: From STAAD.pro analysis and design the values of Vu, Vc and Vs as well as specifications of shear reinforcement is shown below in Figure and Figure . Figure 2-20: Shear Diagram for beam #200
  • 24. 24 | P a g e Figure 2-21: Specifications of shear reinforcement of beam #200 Check: ∅𝑉𝑛 = 𝑉𝑠 + 𝑉𝑐 = 0 + 98.7 = (0.75) × 98.7 = 74.03 𝐾𝑁 ∅𝑉𝑛 ≥ 𝑉𝑢 → 74.03 ≥ 27.62  OK ∅𝑉𝑐 2 > 𝑉𝑢 → 37.01 > 27.62 OK So, no need for stirrups.
  • 25. 25 | P a g e 2.7. Column Design Critical Column found to be beam # 127 as shown in Figure . Figure 2-22: Critical Column #127 The column output given by STAAD.pro for column # 127 is shown in the following table and Figure . SI Unit English Unit 𝑃𝑢 18.03 𝐾𝑁 4.1 𝐾𝑖𝑝 𝑀𝑧 125.14 𝐾𝑁. 𝑚 1107.6 𝐾𝑖𝑝. 𝑖𝑛 𝑀 𝑦 11.96 𝐾𝑁. 𝑚 105.9 𝐾𝑖𝑝. 𝑖𝑛 𝑏 13.78 𝑖𝑛 𝐴 𝑔 0.263 𝑚2 407.7 𝑖𝑛2 𝑑 29.5 𝑖𝑛 𝐴 𝑠 3176 𝑚𝑚2 4.923 𝑖𝑛2 𝑓′ 𝑐 40 𝑀𝑝𝑎 5.8 𝐾𝑠𝑖 𝑓𝑦 420 𝑀𝑝𝑎 60.9 𝐾𝑠𝑖 𝑐𝑜𝑣𝑒𝑟 0.04 𝑚 1.57 𝑖𝑛
  • 26. 26 | P a g e Figure 2-23: Output of column#127 To check the column reinforcement, checking whether the column is short or long should be done first. If the column is long the effect of slenderness should be taken in consideration, if not, no need to consider the effects of slenderness. Slendernen ratio→ 𝑘𝑙 𝑢 𝑟 Check: Since the structure is braced frame  if 𝑘𝑙 𝑢 𝑟 ≤ 34 − 12 𝑀1 𝑀2 it is short column, otherwise it is long column. 34 − 12 𝑀1 𝑀2 = 34 − 12 11.96 125.14 = 32.85 Since the column both fixed ends  𝑘 = 1 𝑙 𝑢 = 3.5 𝑚 𝑟 = √ 𝐼 𝐴 = √ 𝑏ℎ3 12𝑏ℎ = √ 0.750 × 0.3503 12(0.750)(0.350) = 0.101 𝑚𝑚  𝑘𝑙 𝑢 𝑟 = 1(3.5) 0.101 = 34.7 > 33.73, so it is long column. 𝛾 = ℎ − 2 × 𝑐𝑜𝑣. ℎ = 13.78 − 2 × 1.57 13.78 = 0.77 Since that the column has biaxial moments acting on it, the equivalent eccentricity method will be applied.
  • 27. 27 | P a g e Equations used:  𝑥 𝑏 = 87000 𝑓 𝑦+87000 × 𝑑 → 𝑥 𝑏 = 87000 60.9+87000 × 29.5 = 29.48 𝑖𝑛  𝑎 = 𝛽 × 𝑥 𝑏 → 𝑎 = 0.85 × 29.48 = 25.1 𝑖𝑛  𝑐 𝑐 = 0.85 𝑓 𝑐 𝑏𝑎 → 𝑐 𝑐 = 0.85 × 5.8 × 13.78 × 25.1 = 1705 𝐾𝑖𝑝𝑠  𝑇 = 𝐴 𝑠 × 𝑓 𝑦 → 𝑇 = 4.9 × 60.9 = 298.4 𝐾𝑖𝑝𝑠  𝜀𝑠 = 29.5−1.57 29.5 × 0.003 = 0.0028 > 𝑓𝑦 𝐸 𝑠 → 𝑠𝑡𝑒𝑒𝑙 𝑦𝑖𝑒𝑙𝑑𝑒𝑑  𝑐 𝑠 = 𝐴 𝑠 × ( 𝑓 𝑦 − 0.85𝑓 𝑐 ) → 𝑐 𝑠 = 4.9 × (60.9 − 0.85 × 5.8) = 274.3 𝐾𝑖𝑝𝑠  𝑃𝑛 = 𝑐 𝑐 + 𝑐 𝑠 − 𝑇 → 𝑃𝑛 = 1705 + 274.3 − 298.4 = 1680.9 𝐾𝑖𝑝𝑠  𝑀 𝑛 = 1705 (10.64 − 25.1 2 ) + 274.3(10.64 − 2.4) + 298.4(10.64 − 2.4) = 1462.49 𝐾𝑖𝑝 − 𝑓𝑡  𝑒 = 𝑀 𝑛 𝑝 𝑛 → 1462.49 1680.9 = 10.4
  • 28. 28 | P a g e 2.8. Foundation Design Foundations design was done using STAAD.foundation software. 2.8.1. Procedure 1) Analyze the structure using STAAD.pro. 2) Import STAAD.pro file into STAAD.foundation. Figure shows the distribution of isolated footings. Figure 2-24: Footings distribution of Solid Slab Structure 3) Define concrete and rebar parameters as shown in Figure : Figure 2-25: Concrete and Rebar Parameters
  • 29. 29 | P a g e 4) Define cover and soil parameters as shown in Figure 2-26: Figure 2-26: Cover and soil parameters 5) Define footing geometry parameters as shown in Figure : Figure 2-27: Footing geometry parameters
  • 30. 30 | P a g e 2.8.2. Results Below are two tables of footings sizes and reinforcement. Typical steel arrangement and footing sizes are shown in Figure 2-28 and Figure 2-29. Figure 2-28: Typical elevation section of footing Figure 2-29: Typical plan section of footing
  • 31. 31 | P a g e Foundation geometry for shear wall Isolated Footing 21
  • 32. 32 | P a g e Input Values Footing Geomtery Footing Thickness (Ft) : 500.00 mm Footing Length - X (Fl) : 1000.00 mm Footing Width - Z (Fw) : 1000.00 mm Eccentricity along X (Oxd) : 0.00 mm Eccentricity along Z (Ozd) : 0.00 mm Column Dimensions Column Shape : Rectangular Column Length - X (Pl) : 0.75 m Column Width - Z (Pw) : 0.35 m 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
  • 33. 33 | P a g e Design Parameters Concrete and Rebar Properties Unit Weight of Concrete : 25.000 kN/m3 Strength of Concrete : 25.000 N/mm2 Yield Strength of Steel : 415.000 N/mm2 Minimum Bar Size : # 6 Maximum Bar Size : # 40 Minimum Bar Spacing : 50.00 mm Maximum Bar Spacing : 500.00 mm Pedestal Clear Cover (P, CL) : 50.00 mm Footing Clear Cover (F, CL) : 50.00 mm Soil Properties Soil Type : UnDrained Unit Weight : 22.00 kN/m3 Soil Bearing Capacity : 200.00 kN/m2 Soil Surcharge : 0.00 kN/m2 Depth of Soil above Footing : 0.00 mm Undrained Shear Strength : 0.00 N/mm2 Sliding and Overturning Coefficient of Friction : 0.50 Factor of Safety Against Sliding : 1.50 Factor of Safety Against Overturning : 1.50 ------------------------------------------------------
  • 34. 34 | P a g e Design Calculations Footing Size Initial Length (Lo) = 1.00 m Initial Width (Wo) = 1.00 m Applied Loads - Allowable Stress Level LC Axial (kN) Shear X (kN) Shear Z (kN) Moment X (kNm) Moment Z (kNm) 5 74.877 99.102 5.015 1.482 -348.409 6 -279.122 -0.531 137.333 17.802 0.941 7 -67.530 -185.540 -5.085 -1.439 488.882 8 281.613 0.436 -82.371 -13.372 -0.766 9 203.757 -6.409 -1.239 2.688 6.289 10 16.648 -2.920 -0.046 0.267 2.133 11 285.260 -8.973 -1.735 3.763 8.804 12 271.146 -12.363 -1.561 3.654 10.959 13 261.157 -10.611 -1.533 3.493 9.679 14 304.410 71.590 2.525 4.412 -271.181 15 21.211 -8.116 108.379 17.467 8.299 16 190.484 -156.123 -5.555 2.075 398.652 17 469.799 -7.343 -67.384 -7.472 6.934 18 380.960 147.952 6.491 5.865 -547.775 19 -185.438 -11.461 218.200 31.977 11.185 20 153.108 -307.475 -9.669 1.191 791.890 21 711.737 -9.914 -133.327 -17.902 8.455 22 261.157 -10.611 -1.533 3.493 9.679 23 261.157 -10.611 -1.533 3.493 9.679 24 261.157 -10.611 -1.533 3.493 9.679 25 261.157 -10.611 -1.533 3.493 9.679 26 303.185 152.795 6.909 4.791 -551.795 27 -263.213 -6.618 218.618 30.903 7.166 28 75.333 -302.632 -9.251 0.117 787.871 29 633.962 -5.072 -132.909 -18.976 4.435 30 183.381 -5.768 -1.115 2.419 5.660 31 183.381 -5.768 -1.115 2.419 5.660 32 183.381 -5.768 -1.115 2.419 5.660 33 183.381 -5.768 -1.115 2.419 5.660
  • 35. 35 | P a g e Applied Loads - Strength Level LC Axial (kN) Shear X (kN) Shear Z (kN) Moment X (kNm) Moment Z (kNm) 5 74.877 99.102 5.015 1.482 -348.409 6 -279.122 -0.531 137.333 17.802 0.941 7 -67.530 -185.540 -5.085 -1.439 488.882 8 281.613 0.436 -82.371 -13.372 -0.766 9 203.757 -6.409 -1.239 2.688 6.289 10 16.648 -2.920 -0.046 0.267 2.133 11 285.260 -8.973 -1.735 3.763 8.804 12 271.146 -12.363 -1.561 3.654 10.959 13 261.157 -10.611 -1.533 3.493 9.679 14 304.410 71.590 2.525 4.412 -271.181 15 21.211 -8.116 108.379 17.467 8.299 16 190.484 -156.123 -5.555 2.075 398.652 17 469.799 -7.343 -67.384 -7.472 6.934 18 380.960 147.952 6.491 5.865 -547.775 19 -185.438 -11.461 218.200 31.977 11.185 20 153.108 -307.475 -9.669 1.191 791.890 21 711.737 -9.914 -133.327 -17.902 8.455 22 261.157 -10.611 -1.533 3.493 9.679 23 261.157 -10.611 -1.533 3.493 9.679 24 261.157 -10.611 -1.533 3.493 9.679 25 261.157 -10.611 -1.533 3.493 9.679 26 303.185 152.795 6.909 4.791 -551.795 27 -263.213 -6.618 218.618 30.903 7.166 28 75.333 -302.632 -9.251 0.117 787.871 29 633.962 -5.072 -132.909 -18.976 4.435 30 183.381 -5.768 -1.115 2.419 5.660 31 183.381 -5.768 -1.115 2.419 5.660 32 183.381 -5.768 -1.115 2.419 5.660 33 183.381 -5.768 -1.115 2.419 5.660 Reduction of force due to buoyancy = -0.00 kN Effect due to adhesion = 0.00 kN Min. area required from bearing pressure, Amin = P / qmax = 3.621 m2 Area from initial length and width, Ao = Lo * Wo = 1.00 m2
  • 36. 36 | P a g e Final Footing Size Length (L2) = 8.60 m Governing Load Case : # 28 Width (W2) = 8.60 m Governing Load Case : # 28 Depth (D2) = 0.50 m Governing Load Case : # 28 Area (A2) = 73.96 m2 Pressures at Four Corners Load Case Pressure at corner 1 (q1) (kN/m^2) Pressure at corner 2 (q2) (kN/m^2) Pressure at corner 3 (q3) (kN/m^2) Pressure at corner 4 (q4) (kN/m^2) Area of footing in uplift (Au) (m2 ) 20 23.4557 5.6150 5.6837 23.5244 -0.0000 21 21.4516 21.1986 22.7940 23.0471 -0.0000 21 21.4516 21.1986 22.7940 23.0471 -0.0000 18 23.4297 11.6994 11.8712 23.6015 -0.0000 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 4 corners Four Corners Load Case Pressure at corner 1 (q1) (kN/m^2) Pressure at corner 2 (q2) (kN/m^2) Pressure at corner 3 (q3) (kN/m^2) Pressure at corner 4 (q4) (kN/m^2)
  • 37. 37 | P a g e 20 23.4557 5.6150 5.6837 23.5244 21 21.4516 21.1986 22.7940 23.0471 21 21.4516 21.1986 22.7940 23.0471 18 23.4297 11.6994 11.8712 23.6015 Adjust footing size if necessary. Check for stability against overturning and sliding - Factor of safety against sliding Factor of safety against overturning Load Case No. Along X- Direction Along Z- Direction About X- Direction About Z- Direction 5 5.042 99.634 1077.012 10.798 6 607.904 2.350 32.092 2299.745 7 2.309 84.264 925.514 6.335 8 1384.520 7.321 95.058 5274.047 9 88.014 455.234 2345.246 511.025 10 161.146 10206.828 16563.146 1126.246 11 67.409 348.657 1796.190 391.387 12 48.353 383.021 1789.319 299.929
  • 38. 38 | P a g e 13 55.866 386.674 1869.768 340.213 14 8.583 243.336 931.256 17.213 15 58.261 4.363 56.748 329.068 16 3.571 100.358 6821.752 10.057 17 94.942 10.346 145.646 565.310 18 4.412 100.556 616.140 9.028 19 32.242 1.693 22.525 187.861 20 1.752 55.724 1271.710 4.900 21 82.517 6.136 83.198 524.584 22 55.866 386.674 1869.768 340.213 23 55.866 386.674 1869.768 340.213 24 55.866 386.674 1869.768 340.213 25 55.866 386.674 1869.768 340.213 26 4.017 88.846 640.209 8.403 27 49.961 1.512 20.279 271.454 28 1.652 54.037 953.567 4.577 29 153.646 5.863 78.441 961.341 30 96.027 496.681 2558.767 557.551 31 96.027 496.681 2558.767 557.551 32 96.027 496.681 2558.767 557.551 33 96.027 496.681 2558.767 557.551 Critical Load Case And The Governing Factor Of Safety For Overturning And Sliding - X Direction Critical Load Case for Sliding along X-Direction : 28 Governing Disturbing Force : -302.632 kN Governing Restoring Force : 499.900 kN Minimum Sliding Ratio for the Critical Load Case : 1.652 Critical Load Case for Overturning about X-Direction : 27 Governing Overturning Moment : 140.210 kNm Governing Resisting Moment : 2843.342 kNm Minimum Overturning Ratio for the Critical Load Case : 20.279
  • 39. 39 | P a g e Critical Load Case And The Governing Factor Of Safety For Overturning And Sliding - Z Direction Critical Load Case for Sliding along Z-Direction : 27 Governing Disturbing Force : 218.618 kN Governing Restoring Force : 330.627 kN Minimum Sliding Ratio for the Critical Load Case : 1.512 Critical Load Case for Overturning about Z-Direction : 28 Governing Overturning Moment : 939.184 kNm Governing Resisting Moment : 4299.062 kNm Minimum Overturning Ratio for the Critical Load Case : 4.577 Shear Calculation Punching Shear Check Total Footing Depth, D = 0.50m Calculated Effective Depth, deff = D - Ccover - 1.0 = 0.42 m
  • 40. 40 | P a g e For rectangular column, = Bcol / Dcol = 2.14 Effective depth, deff, increased until 0.75*Vc Punching Shear Force Punching Shear Force, Vu = 702.98 kN, Load Case # 21 From ACI Cl.11.12.2.1, bo for column= 3.90 m Equation 11-33, Vc1 = 2657.25 kN Equation 11-34, Vc2 = 4368.42 kN Equation 11-35, Vc3 = 2748.88 kN Punching shear strength, Vc = 0.75 * minimum of (Vc1, Vc2, Vc3) = 1992.94 kN 0.75 * Vc > Vu hence, OK One-Way Shear Check Along X Direction From ACI Cl.11.3.1.1, Vc = 3032.06 kN Distance along Z to design for shear, Dz = 4.90 m
  • 41. 41 | P a g e Check that 0.75 * Vc > Vux where Vux is the shear force for the critical load cases at a distance deff from the face of the column caused by bending about the X axis. From above calculations, 0.75 * Vc = 2274.05 kN Critical load case for Vux is # 21 320.71 kN 0.75 * Vc > Vux hence, OK Along Z Direction From ACI Cl.11.3.1.1, Vc = 3032.06 kN Distance along X to design for shear, Dx = 3.50 m Check that 0.75 * Vc > Vuz where Vuz is the shear force for the critical load cases at a distance deff from the face of the column caused by bending about the Z axis. From above calculations, 0.75 * Vc = 2274.05 kN
  • 42. 42 | P a g e Critical load case for Vuz is # 21 291.95 kN 0.75 * Vc > Vuz hence, OK Design for Flexure about Z axis Calculate the flexural reinforcement along the X direction of the footing. Find the area of steel required, A, as per Section 3.8 of Reinforced Concrete Design (5th ed.) by Salmon and Wang (Ref. 1) Critical Load Case # 21 The strength values of steel and concrete used in the formulae are in ksi Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85 From ACI Cl. 10.3.2, = 0.02573 From ACI Cl. 10.3.3, = 0.01929 From ACI Cl. 7.12.2, = 0.00180 From Ref. 1, Eq. 3.8.4a, constant m = 19.53
  • 43. 43 | P a g e Calculate reinforcement ratio for critical load case Design for flexure about Z axis is performed at the face of the column at a distance, Dx = 3.93 m Ultimate moment, 643.30 kNm Nominal moment capacity, Mn = 714.78 kNm Required = 0.00180 Since OK Area of Steel Required, As = 10.19 in2 Find suitable bar arrangement between minimum and maximum rebar sizes Available development length for bars, DL = 3875.00 mm Try bar size # 8 Area of one bar = 0.08 in2 Number of bars required, Nbar = 131 Because the number of bars is rounded up, make sure new reinforcement ratio < max Total reinforcement area, As_total = Nbar * (Area of one bar) = 10.21 in2 deff = D - Ccover - 0.5 * (dia. of one bar) = 0.45 m Reinforcement ratio, = 0.00172 From ACI Cl.7.6.1, minimum req'd clear distance between bars, Cd = max (Diameter of one bar, 1.0, Min. User Spacing) = 65.32 mm Check to see if width is sufficient to accomodate bars
  • 44. 44 | P a g e Design for Flexure about X axis Calculate the flexural reinforcement along the Z direction of the footing. Find the area of steel required, A, as per Section 3.8 of Reinforced Concrete Design (5th ed.) by Salmon and Wang (Ref. 1) Critical Load Case # 21 The strength values of steel and concrete used in the formulae are in ksi Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85 From ACI Cl. 10.3.2, = 0.02573 From ACI Cl. 10.3.3, = 0.01929 From ACI Cl.7.12.2, = 0.00180 From Ref. 1, Eq. 3.8.4a, constant m = 19.53 Calculate reinforcement ratio for critical load case Design for flexure about X axis is performed at the face of the column at a distance, Dz = 4.47 m Ultimate moment, 743.82 kNm
  • 45. 45 | P a g e Nominal moment capacity, Mn = 826.46 kNm Required = 0.00180 Since OK Area of Steel Required, As = 10.00 in2 Find suitable bar arrangement between minimum and maximum rebar sizes Available development length for bars, DL = 4075.00 mm Try bar size # 8 Area of one bar = 0.08 in2 Number of bars required, Nbar = 129 Because the number of bars is rounded up, make sure new reinforcement ratio < max Total reinforcement area, As_total = Nbar * (Area of one bar) = 10.05 in2 deff = D - Ccover - 0.5 * (dia. of one bar) = 0.42 m Reinforcement ratio, = 0.00179 From ACI Cl.7.6.1, minimum req'd clear distance between bars, Cd = max (Diameter of one bar, 1.0, Min. User Spacing) = 58.34 mm Check to see if width is sufficient to accomodate bars Bending moment for uplift cases will be calculated based solely on selfweight, soil depth and surcharge loading. As the footing size has already been determined based on all servicebility load cases, and design moment calculation is based on selfweight, soil depth and surcharge only, top reinforcement value for all pure uplift load cases will be the same.
  • 46. 46 | P a g e Design For Top Reinforcement About Z Axis Calculate the flexural reinforcement along the X direction of the footing. Find the area of steel required The strength values of steel and concrete used in the formulae are in ksi Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85 From ACI Cl. 10.3.2, = 0.02573 From ACI Cl. 10.3.3, = 0.01929 From ACI Cl. 7.12.2, = 0.00180 From Ref. 1, Eq. 3.8.4a, constant m = 19.53 Calculate reinforcement ratio for critical load case Design for flexure about A axis is performed at the face of the column at a distance, Dx = 4.13 m Ultimate moment, 0.00 kNm Nominal moment capacity, Mn = 0.00 kNm Required = 0.00180 Since OK Area of Steel Required, As = 10.00 in2 Find suitable bar arrangement between minimum and maximum rebar sizes
  • 47. 47 | P a g e Design For Top Reinforcement About X Axis First load case to be in pure uplift # 0 Calculate the flexural reinforcement along the Z direction of the footing. Find the area of steel required The strength values of steel and concrete used in the formulae are in ksi Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85 From ACI Cl. 10.3.2, = 0.02573 From ACI Cl. 10.3.3, = 0.01929 From ACI Cl.7.12.2, = 0.00180 From Ref. 1, Eq. 3.8.4a, constant m = 19.53 Calculate reinforcement ratio for critical load case Design for flexure about A axis is performed at the face of the column at a distance, Dx = 3.93 m Ultimate moment, 0.00 kNm Nominal moment capacity, Mn = 0.00 kNm Required = 0.00180 Since OK Area of Steel Required, As = 10.19 in2 Find suitable bar arrangement between minimum and maximum rebar sizes
  • 48. 48 | P a g e Foundation geometry Isolated Footing 22
  • 49. 49 | P a g e Input Values Footing Geomtery Footing Thickness (Ft) : 500.00 mm Footing Length - X (Fl) : 1000.00 mm Footing Width - Z (Fw) : 1000.00 mm Eccentricity along X (Oxd) : 0.00 mm Eccentricity along Z (Ozd) : 0.00 mm Column Dimensions Column Shape : Rectangular Column Length - X (Pl) : 0.35 m Column Width - Z (Pw) : 0.75 m 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 Design Parameters Concrete and Rebar Properties
  • 50. 50 | P a g e Unit Weight of Concrete : 25.000 kN/m3 Strength of Concrete : 25.000 N/mm2 Yield Strength of Steel : 415.000 N/mm2 Minimum Bar Size : # 6 Maximum Bar Size : # 40 Minimum Bar Spacing : 50.00 mm Maximum Bar Spacing : 500.00 mm Pedestal Clear Cover (P, CL) : 50.00 mm Footing Clear Cover (F, CL) : 50.00 mm Soil Properties Soil Type : UnDrained Unit Weight : 22.00 kN/m3 Soil Bearing Capacity : 200.00 kN/m2 Soil Surcharge : 0.00 kN/m2 Depth of Soil above Footing : 0.00 mm Undrained Shear Strength : 0.00 N/mm2 Sliding and Overturning Coefficient of Friction : 0.50 Factor of Safety Against Sliding : 1.50 Factor of Safety Against Overturning : 1.50 ------------------------------------------------------
  • 51. 51 | P a g e Design Calculations Footing Size Initial Length (Lo) = 1.00 m Initial Width (Wo) = 1.00 m Applied Loads - Allowable Stress Level LC Axial (kN) Shear X (kN) Shear Z (kN) Moment X (kNm) Moment Z (kNm) 5 143.492 39.564 0.810 2.667 -89.934 6 -51.735 -0.158 133.489 212.281 0.228 7 -161.307 -116.049 -0.540 -1.791 131.958 8 51.575 0.137 -59.207 -172.287 -0.191 9 295.056 5.351 -7.561 -5.781 -4.472 10 44.544 3.108 0.009 0.022 -2.647 11 413.078 7.491 -10.585 -8.094 -6.261 12 425.337 11.393 -9.058 -6.903 -9.602 13 398.611 9.529 -9.064 -6.916 -8.014 14 468.860 38.072 -8.425 -4.804 -77.314 15 312.678 6.294 97.718 162.887 -5.184 16 225.021 -86.419 -9.505 -8.370 100.199 17 395.327 6.530 -56.439 -144.767 -5.519 18 628.197 72.830 -7.768 -2.648 -151.908 19 315.834 9.275 204.519 332.734 -7.648 20 140.520 -176.150 -9.928 -9.781 203.118 21 481.131 9.747 -103.795 -282.574 -8.319 22 398.611 9.529 -9.064 -6.916 -8.014 23 398.611 9.529 -9.064 -6.916 -8.014 24 398.611 9.529 -9.064 -6.916 -8.014 25 398.611 9.529 -9.064 -6.916 -8.014 26 495.137 68.117 -5.509 -0.935 -147.920 27 182.774 4.562 206.778 334.446 -3.660 28 7.459 -180.863 -7.669 -8.068 207.107 29 348.070 5.034 -101.536 -280.861 -4.330 30 265.550 4.816 -6.805 -5.203 -4.025 31 265.550 4.816 -6.805 -5.203 -4.025 32 265.550 4.816 -6.805 -5.203 -4.025 33 265.550 4.816 -6.805 -5.203 -4.025
  • 52. 52 | P a g e Applied Loads - Strength Level LC Axial (kN) Shear X (kN) Shear Z (kN) Moment X (kNm) Moment Z (kNm) 5 143.492 39.564 0.810 2.667 -89.934 6 -51.735 -0.158 133.489 212.281 0.228 7 -161.307 -116.049 -0.540 -1.791 131.958 8 51.575 0.137 -59.207 -172.287 -0.191 9 295.056 5.351 -7.561 -5.781 -4.472 10 44.544 3.108 0.009 0.022 -2.647 11 413.078 7.491 -10.585 -8.094 -6.261 12 425.337 11.393 -9.058 -6.903 -9.602 13 398.611 9.529 -9.064 -6.916 -8.014 14 468.860 38.072 -8.425 -4.804 -77.314 15 312.678 6.294 97.718 162.887 -5.184 16 225.021 -86.419 -9.505 -8.370 100.199 17 395.327 6.530 -56.439 -144.767 -5.519 18 628.197 72.830 -7.768 -2.648 -151.908 19 315.834 9.275 204.519 332.734 -7.648 20 140.520 -176.150 -9.928 -9.781 203.118 21 481.131 9.747 -103.795 -282.574 -8.319 22 398.611 9.529 -9.064 -6.916 -8.014 23 398.611 9.529 -9.064 -6.916 -8.014 24 398.611 9.529 -9.064 -6.916 -8.014 25 398.611 9.529 -9.064 -6.916 -8.014 26 495.137 68.117 -5.509 -0.935 -147.920 27 182.774 4.562 206.778 334.446 -3.660 28 7.459 -180.863 -7.669 -8.068 207.107 29 348.070 5.034 -101.536 -280.861 -4.330 30 265.550 4.816 -6.805 -5.203 -4.025 31 265.550 4.816 -6.805 -5.203 -4.025 32 265.550 4.816 -6.805 -5.203 -4.025 33 265.550 4.816 -6.805 -5.203 -4.025
  • 53. 53 | P a g e Reduction of force due to buoyancy = -0.00 kN Effect due to adhesion = 0.00 kN Min. area required from bearing pressure, Amin = P / qmax = 3.203 m2 Area from initial length and width, Ao = Lo * Wo = 1.00 m2 Final Footing Size Length (L2) = 6.55 m Governing Load Case : # 28 Width (W2) = 6.55 m Governing Load Case : # 28 Depth (D2) = 0.50 m Governing Load Case : # 28 Area (A2) = 42.90 m2 Pressures at Four Corners Load Case Pressure at corner 1 (q1) (kN/m^2) Pressure at corner 2 (q2) (kN/m^2) Pressure at corner 3 (q3) (kN/m^2) Pressure at corner 4 (q4) (kN/m^2) Area of footing in uplift (Au) (m2 ) 18 31.0236 22.9815 23.2604 31.3025 -0.0000 18 31.0236 22.9815 23.2604 31.3025 -0.0000 21 16.8542 16.2908 30.5740 31.1373 -0.0000 18 31.0236 22.9815 23.2604 31.3025 -0.0000 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.
  • 54. 54 | P a g e Summary of Adjusted Pressures at 4 corners Four Corners Load Case Pressure at corner 1 (q1) (kN/m^2) Pressure at corner 2 (q2) (kN/m^2) Pressure at corner 3 (q3) (kN/m^2) Pressure at corner 4 (q4) (kN/m^2) 18 31.0236 22.9815 23.2604 31.3025 18 31.0236 22.9815 23.2604 31.3025 21 16.8542 16.2908 30.5740 31.1373 18 31.0236 22.9815 23.2604 31.3025 Adjust footing size if necessary. Check for stability against overturning and sliding - Factor of safety against sliding Factor of safety against overturning Load Case No. Along X- Direction Along Z- Direction About X- Direction About Z- Direction 5 8.591 419.533 724.576 20.290 6 1528.905 1.815 5.687 5158.545 7 1.616 347.159 595.886 6.464
  • 55. 55 | P a g e 8 2152.745 4.964 9.536 7438.992 9 77.684 54.975 284.738 380.895 10 93.442 31772.244 72461.427 452.804 11 63.366 44.843 232.259 310.693 12 42.200 53.078 275.476 205.850 13 49.056 51.572 267.451 239.604 14 13.200 59.652 365.102 34.164 15 67.440 4.344 13.130 333.715 16 4.405 40.046 189.993 17.385 17 71.331 8.253 17.637 347.314 18 7.994 74.956 583.845 20.250 19 45.935 2.083 6.415 227.138 20 1.921 34.085 150.320 7.612 21 52.190 4.901 9.962 252.570 22 49.056 51.572 267.451 239.604 23 49.056 51.572 267.451 239.604 24 49.056 51.572 267.451 239.604 25 49.056 51.572 267.451 239.604 26 7.571 93.618 915.493 18.561 27 78.806 1.739 5.378 396.381 28 1.503 35.450 149.604 5.985 29 87.835 4.355 8.733 422.980 30 83.252 58.916 305.147 408.195 31 83.252 58.916 305.147 408.195 32 83.252 58.916 305.147 408.195 33 83.252 58.916 305.147 408.195 Critical Load Case And The Governing Factor Of Safety For Overturning And Sliding - X Direction Critical Load Case for Sliding along X-Direction : 28 Governing Disturbing Force : -180.863 kN Governing Restoring Force : 271.861 kN Minimum Sliding Ratio for the Critical Load Case : 1.503
  • 56. 56 | P a g e Critical Load Case for Overturning about X-Direction : 27 Governing Overturning Moment : 437.833 kNm Governing Resisting Moment : 2354.800 kNm Minimum Overturning Ratio for the Critical Load Case : 5.378 Critical Load Case And The Governing Factor Of Safety For Overturning And Sliding - Z Direction Critical Load Case for Sliding along Z-Direction : 27 Governing Disturbing Force : 206.778 kN Governing Restoring Force : 359.518 kN Minimum Sliding Ratio for the Critical Load Case : 1.739 Critical Load Case for Overturning about Z-Direction : 28 Governing Overturning Moment : 297.537 kNm Governing Resisting Moment : 1780.656 kNm Minimum Overturning Ratio for the Critical Load Case : 5.985
  • 57. 57 | P a g e Shear Calculation Punching Shear Check Total Footing Depth, D = 0.50m Calculated Effective Depth, deff = D - Ccover - 1.0 = 0.42 m For rectangular column, = Bcol / Dcol = 2.14 Effective depth, deff, increased until 0.75*Vc Punching Shear Force Punching Shear Force, Vu = 614.87 kN, Load Case # 18 From ACI Cl.11.12.2.1, bo for column= 3.90 m Equation 11-33, Vc1 = 2657.25 kN Equation 11-34, Vc2 = 4368.42 kN Equation 11-35, Vc3 = 2748.88 kN Punching shear strength, Vc = 0.75 * minimum of (Vc1, Vc2, Vc3) = 1992.94 kN 0.75 * Vc > Vu hence, OK
  • 58. 58 | P a g e One-Way Shear Check Along X Direction From ACI Cl.11.3.1.1, Vc = 2309.30 kN Distance along Z to design for shear, Dz = 4.07 m Check that 0.75 * Vc > Vux where Vux is the shear force for the critical load cases at a distance deff from the face of the column caused by bending about the X axis. From above calculations, 0.75 * Vc = 1731.98 kN Critical load case for Vux is # 21 253.86 kN 0.75 * Vc > Vux hence, OK
  • 59. 59 | P a g e Along Z Direction From ACI Cl.11.3.1.1, Vc = 2309.30 kN Distance along X to design for shear, Dx = 2.68 m Check that 0.75 * Vc > Vuz where Vuz is the shear force for the critical load cases at a distance deff from the face of the column caused by bending about the Z axis. From above calculations, 0.75 * Vc = 1731.98 kN Critical load case for Vuz is # 18 298.27 kN 0.75 * Vc > Vuz hence, OK
  • 60. 60 | P a g e Design for Flexure about Z axis Calculate the flexural reinforcement along the X direction of the footing. Find the area of steel required, A, as per Section 3.8 of Reinforced Concrete Design (5th ed.) by Salmon and Wang (Ref. 1) Critical Load Case # 18 The strength values of steel and concrete used in the formulae are in ksi Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85 From ACI Cl. 10.3.2, = 0.02573 From ACI Cl. 10.3.3, = 0.01929 From ACI Cl. 7.12.2, = 0.00180 From Ref. 1, Eq. 3.8.4a, constant m = 19.53 Calculate reinforcement ratio for critical load case Design for flexure about Z axis is performed at the face of the column at a distance, Dx = 3.10 m Ultimate moment, 547.42 kNm
  • 61. 61 | P a g e Nominal moment capacity, Mn = 608.24 kNm Required = 0.00180 Since OK Area of Steel Required, As = 7.76 in2 Find suitable bar arrangement between minimum and maximum rebar sizes Available development length for bars, DL = 3050.00 mm Try bar size # 8 Area of one bar = 0.08 in2 Number of bars required, Nbar = 100 Because the number of bars is rounded up, make sure new reinforcement ratio < max Total reinforcement area, As_total = Nbar * (Area of one bar) = 7.79 in2 deff = D - Ccover - 0.5 * (dia. of one bar) = 0.45 m Reinforcement ratio, = 0.00172 From ACI Cl.7.6.1, minimum req'd clear distance between bars, Cd = max (Diameter of one bar, 1.0, Min. User Spacing) = 65.07 mm Check to see if width is sufficient to accomodate bars
  • 62. 62 | P a g e Design for Flexure about X axis Calculate the flexural reinforcement along the Z direction of the footing. Find the area of steel required, A, as per Section 3.8 of Reinforced Concrete Design (5th ed.) by Salmon and Wang (Ref. 1) Critical Load Case # 21 The strength values of steel and concrete used in the formulae are in ksi Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85 From ACI Cl. 10.3.2, = 0.02573 From ACI Cl. 10.3.3, = 0.01929 From ACI Cl.7.12.2, = 0.00180 From Ref. 1, Eq. 3.8.4a, constant m = 19.53 Calculate reinforcement ratio for critical load case Design for flexure about X axis is performed at the face of the column at a distance, Dz = 3.65 m Ultimate moment, 447.60 kNm
  • 63. 63 | P a g e Nominal moment capacity, Mn = 497.34 kNm Required = 0.00180 Since OK Area of Steel Required, As = 7.61 in2 Find suitable bar arrangement between minimum and maximum rebar sizes Available development length for bars, DL = 2850.00 mm Try bar size # 8 Area of one bar = 0.08 in2 Number of bars required, Nbar = 98 Because the number of bars is rounded up, make sure new reinforcement ratio < max Total reinforcement area, As_total = Nbar * (Area of one bar) = 7.64 in2 deff = D - Ccover - 0.5 * (dia. of one bar) = 0.42 m Reinforcement ratio, = 0.00178 From ACI Cl.7.6.1, minimum req'd clear distance between bars, Cd = max (Diameter of one bar, 1.0, Min. User Spacing) = 58.41 mm Check to see if width is sufficient to accomodate bars Bending moment for uplift cases will be calculated based solely on selfweight, soil depth and surcharge loading. As the footing size has already been determined based on all servicebility load cases, and design moment calculation is based on selfweight, soil depth and surcharge only, top reinforcement value for all pure uplift load cases will be the same. Design For Top Reinforcement About Z Axis Calculate the flexural reinforcement along the X direction of the footing. Find the area of steel required
  • 64. 64 | P a g e The strength values of steel and concrete used in the formulae are in ksi Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85 From ACI Cl. 10.3.2, = 0.02573 From ACI Cl. 10.3.3, = 0.01929 From ACI Cl. 7.12.2, = 0.00180 From Ref. 1, Eq. 3.8.4a, constant m = 19.53 Calculate reinforcement ratio for critical load case Design for flexure about A axis is performed at the face of the column at a distance, Dx = 2.90 m Ultimate moment, 0.00 kNm Nominal moment capacity, Mn = 0.00 kNm Required = 0.00180 Since OK Area of Steel Required, As = 7.61 in2 Find suitable bar arrangement between minimum and maximum rebar sizes
  • 65. 65 | P a g e Design For Top Reinforcement About X Axis First load case to be in pure uplift # 0 Calculate the flexural reinforcement along the Z direction of the footing. Find the area of steel required The strength values of steel and concrete used in the formulae are in ksi Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85 From ACI Cl. 10.3.2, = 0.02573 From ACI Cl. 10.3.3, = 0.01929 From ACI Cl.7.12.2, = 0.00180 From Ref. 1, Eq. 3.8.4a, constant m = 19.53 Calculate reinforcement ratio for critical load case Design for flexure about A axis is performed at the face of the column at a distance, Dx = 3.10 m Ultimate moment, 0.00 kNm Nominal moment capacity, Mn = 0.00 kNm Required = 0.00180 Since OK Area of Steel Required, As = 7.76 in2 Find suitable bar arrangement between minimum and maximum rebar sizes
  • 66. 66 | P a g e Conclusion I had the opportunity to learn how to use STAAD Pro software to analyze and design two-way solid slab as well as one-way ribbed slab. Also, a hand calculation check on analysis of the results of typical structural members gave us knowledge about checking the adequacy of design to meet the criteria set by codes of practice. Furthermore, i was exposed to STAAD Pro Foundation Software, which gave us new ideas about designing the foundations of a building. Additionally, in CE 315 project i had the chance to design a beam, column and foundation.
  • 67. 67 | P a g e References  ACI Committee. Building Code Requirements for Structural Concrete (ACI 318-08) and Commentary. Farmington Hills: American Concrete Institute, 2008.  JAMES, K WIGHT and G MACGREGOR JAMES. REINFORCED CONCRETE Mechanics and Design. New Jersey: Pearson Education, 2012.