Zapata Staad.foundation Memoria

8/12/2019 Zapata Staad.foundation Memoria

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Isolated Footing Design(ACI 318-05)

Design For Isolated Footing 1

Footing No. Group ID Foundation Geometry

- - Length Width Thickness

1 1 2.900 m 2.900 m 0.400 m

Page 1 of 20Isolated Footing Design

23/07/2013file://D:\Staad Foundation Advanced\CalcXsl\footing.xml


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Footing No. Footing Reinforcement Pedestal Reinforcement

-

BottomReinforcement

(Mz)

BottomReinforcement

(Mx)

TopReinforcement

(Mz)

TopReinforcement

(Mx)Main Steel Trans Steel

1#5 @ 22 cm

c/c#5 @ 20 cm

c/c#4 @ 22 cm

c/c#4 @ 22 cm

c/cN/A N/A




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Isolated Footing 1

Input Values

Footing Geomtery

Footing Thickness (Ft) : 0.40 m

Footing Length - X (Fl) : 1.00 m

Footing Width - Z (Fw) : 1.00 m

Eccentricity along X (Oxd) : 0.00 m

Eccentricity along Z (Ozd) : 0.00 m




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Column Dimensions

Pedestal

Design Parameters

Concrete and Rebar Properties

Soil Properties

Sliding and Overturning

Column Shape : Rectangular

Column Length - X (Pl) : 0.50 m

Column Width - Z (Pw) : 0.50 m

Include Pedestal? No

Pedestal Shape : N/A

Pedestal Height (Ph) : N/A

Pedestal Length - X (Pl) : N/A

Pedestal Width - Z (Pw) : N/A

Unit Weight of Concrete : 2400.000 kg/m3

Strength of Concrete : 4.000 ksi

Yield Strength of Steel : 60.000 ksi

Minimum Bar Size : # 4

Maximum Bar Size : # 10

Minimum Bar Spacing : 10.00 cm

Maximum Bar Spacing : 30.00 cm

Pedestal Clear Cover (P, CL) : 8.00 cm

Footing Clear Cover (F, CL) : 8.00 cm

Soil Type : Drained

Unit Weight : 1600.00 kg/m3

Soil Bearing Capacity : 205.95 kN/m2

Soil Surcharge : 0.00 kip/in2

Depth of Soil above Footing : 0.70 m

Cohesion : 0.00 kip/ft2

Coefficient of Friction : 0.50

Factor of Safety Against Sliding : 1.50

Factor of Safety Against Overturning : 1.50




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Design Calculations

Footing Size

Initial Length (Lo) = 1.00 m

Initial Width (Wo) = 1.00 m

Applied Loads - Allowable Stress Level

LCAxial

(Mtonf)

Shear X

(Mtonf)

Shear Z

(Mtonf)

Moment X

(kNm)

Moment Z

(kNm)101 79.860 2.790 11.840 132.880 166.713




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Applied Loads - Strength Level

LCAxial

(Mtonf)Shear X(Mtonf)

Shear Z(Mtonf)

Moment X(kNm)

Moment Z(kNm)

102 79.860 2.790 11.840 132.880 166.713




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Final Footing Size

Reduction of force due to buoyancy = -0.00 MtonfEffect due to adhesion = 0.00 Mtonf

Min. area required from bearing pressure, Amin

= P / qmax

= 3.888 m2

Area from initial length and width, Ao= Lo* Wo= 1.00 m2

Length (L2) = 2.90 m Governing Load Case : # 101

Width (W2) = 2.90 m Governing Load Case : # 101

Depth (D2) = 0.40 m Governing Load Case : # 101

Area (A2) = 8.41 m2




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Check for stability against overturning and sliding

Critical Load Case And The Governing Factor Of Safety For Overturning And Sliding - X Direction

Critical Load Case And The Governing Factor Of Safety For Overturning And Sliding - Z Direction

- Factor of safety againstsliding

Factor of safety againstoverturning

Load CaseNo.

Along X-Direction

Along Z-Direction

About X-Direction

About Z-Direction

101 17.397 4.099 7.697 8.861

Critical Load Case for Sliding along X-Direction : 101

Governing Disturbing Force : 2.790 Mtonf

Governing Restoring Force : 48.536 Mtonf

Minimum Sliding Ratio for the Critical Load Case : 17.397

Critical Load Case for Overturning about X-Direction : 101

Governing Overturning Moment : 179.324 kNm

Governing Resisting Moment : 1380.316 kNm

Minimum Overturning Ratio for the Critical Load Case : 7.697

Critical Load Case for Sliding along Z-Direction : 101

Governing Disturbing Force : 11.840 Mtonf

Governing Restoring Force : 48.536 Mtonf

Minimum Sliding Ratio for the Critical Load Case : 4.099

Critical Load Case for Overturning about Z-Direction : 101

Governing Overturning Moment : 155.769 kNm

Governing Resisting Moment : 1380.316 kNm




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Minimum Overturning Ratio for the Critical Load Case : 8.861




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Shear Calculation

Punching Shear Check

Effective depth, deff

, increased until 0.75*Vc Punching Shear Force

Punching Shear Force, Vu = 73.86 Mtonf, Load Case # 102

Total Footing Depth, D = 0.40m

Calculated Effective Depth, deff

= D - Ccover

- 1.0 = 0.29 m

For rectangular column, = Bcol/ Dcol= 1.00

From ACI Cl.11.12.2.1, bofor column= 3.18 m

Equation 11-33, Vc1

= 249.82 Mtonf

Equation 11-34, Vc2

= 237.64 Mtonf

Equation 11-35, Vc3

= 166.54 Mtonf

Punching shear strength, Vc= 0.75 * minimum of (V

c1, V

c2, V

c3) = 124.91 Mtonf

0.75 * Vc> V

uhence, OK




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One-Way Shear Check

Along X Direction

Check that 0.75 * Vc> V

uxwhere V

uxis the shear force for the critical load cases at a distance d

efffrom the

face of the column caused by bending about the X axis.

Along Z Direction

From ACI Cl.11.3.1.1, Vc= 75.98 Mtonf

Distance along Z to design for shear, Dz= 1.99 m

From above calculations, 0.75 * Vc= 56.98 Mtonf

Critical load case for Vux

is # 102 33.06 Mtonf

0.75 * Vc> Vuxhence, OK




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Check that 0.75 * Vc> V

uzwhere V

uzis the shear force for the critical load cases at a distance d

efffrom the

face of the column caused by bending about the Z axis.

From ACI Cl.11.3.1.1, Vc= 75.98 Mtonf

Distance along X to design for shear, Dx= 0.91 m

From above calculations, 0.75 * Vc= 56.98 Mtonf

Critical load case for Vuz

is # 102 31.99 Mtonf

0.75 * Vc> V

uzhence, OK




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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 # 102

The strength values of steel and concrete used in the formulae are in ksi

Calculate reinforcement ratio for critical load case

Factor from ACI Cl.10.2.7.3 for Fc' 4 ksi, 0.85

From ACI Cl. 10.3.2, = 0.02851

From ACI Cl. 10.3.3, = 0.02138

From ACI Cl. 7.12.2, = 0.00180

From Ref. 1, Eq. 3.8.4a, constant m = 17.65

Design for flexure about Z axis isperformed at the face of the column

at a distance, Dx=

1.20 m

Ultimate moment, 252.36 kNm

Nominal moment capacity, Mn= 280.40 kNm

Required = 0.00276

Since OK

Area of Steel Required, As= 3.66 in2




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Find suitable bar arrangement between minimum and maximum rebar sizes

Because the number of bars is rounded up, make sure new reinforcement ratio

Zapata Staad.foundation Memoria

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