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  • Prestresed Concrete
    • Introduction to prestressed concrete
    • Methods of prestressing
    • Design of PSC members
    • Prestressing force and Ecentricity
    • Ecentricity limits and tendon profile
    • Losses in prestressed concrete structures

  • tanks
    • Introduction to water tanks
    • Load conditions and flexure details for water tanks
    • Minimum and Maximum reinforcement for tanks
    • Slab design for Tanks
    • Design Requirement of Concrete in tanks
    • General design requirements for members of a tank
    • Circular tank Analysis
    • Numerical on the analysis of Circular water tank
    • Design of Rectangular tanks
    • Numerical on Rectangular water tank
    • Underground Tanks
    • Overhead tanks

  • Retaining walls
    • Retaining walls and their types
    • Earth Pressure and Stablity requirements
    • Proportioning and design of cantilever and counterfort walls
    • Numerical on design of a Retaining wall

  • footings
    • Introduction to footings
    • Soil Pressure under Isolated footings
    • General Design Considerations for Footings
    • Special case of Footing
    • Numerical on footings
    • Design of Combined Footing

  • Flat slabs
    • Introduction to flat slabs
    • Proportioning of flat slabs
    • Determination of bending moment and shear force
    • Slab reinforcement
    • Numericals of flat slab

Branch : Civil Engineering
Subject : Design of Concrete Structures-II
Unit : Retaining walls

Numerical on design of a Retaining wall


Q. Determine suitable dimensions of a cantilever retaining wall, which is required to support a bank of earth 4.0 m high above the ground level on the toe side of the wall. Consider the backfill surface to be inclined at an angle of 15o with the horizontal. Assume good soil for foundation at a depth of 1.25 m below the ground level with a safe bearing capacity of 160 kN/m2. Further assume the backfill to comprise granular soil with a unit weight of 16 kN/m3 and an angle of shearing resistance of 30o. Assume the coefficient of friction between soil and concrete to be 0.5.

SOLUTION

2. Preliminary proportions

• Thickness of footing base slab ≈ 0.08h = 0.08 × 5.25 = 0.42 m
Assume a thickness of 420 mm.
• Assume a stem thickness of 450 mm at the base of the stem, tapering to a value of 150 mm at the top of the wall.
• For an economical proportioning of the length L of the base slab, it will be assumed that the vertical reaction R at the footing base is in line with the front face of the stem. For such a condition, (assuming the height above top of wall to be about 0.4 m), the length of the heel slab (inclusive of stem thickness)

• Assuming a triangular base pressure distribution,

L = 1.5X = 3.0 m

3. Stability against overturning

= 5250 2000 tan 15o = 5786 mm

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