What is the minimum factor of safety against sliding for a quay wall under operational conditions?

A minimum factor of safety of 1.5 is recommended for static/operational conditions as per Clause 6.2.2.1.

What grade of concrete is recommended for the blocks?

The minimum grade for plain concrete blocks is M15, and for reinforced concrete blocks is M20 (Clause 5.1.1).

How is stability against overturning checked?

The sum of restoring moments should be at least 1.5 times the sum of overturning moments about the toe of the wall for static conditions (Clause 6.2.2.1).

What are the main design loads to consider for a block work structure?

Key loads include self-weight, wave forces, hydrostatic and earth pressures, surcharge, berthing/mooring forces, and seismic loads (Clause 6.1).

IS 9527

: 2000

Code of practice for design and construction of port and harbour structures, Part 6: Block work

CurrentSpecializedCode of PracticeBIMStructural Engineering · Ports and Harbours

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This standard (Part 6 of IS 9527) provides guidelines for the design and construction of port and harbour structures using precast concrete or stone blocks. It covers material specifications, stability analysis against environmental loads like waves and earthquakes, and construction methodologies for assets like quay walls and breakwaters.

Code of practice for design and construction of port and harbour structures, Part 6: Block work

Quick Reference Values

Minimum Factor of Safety against Sliding (Static)1.5

Minimum Factor of Safety against Overturning (Static)1.5

Minimum Factor of Safety against Sliding (Seismic)1.2

Minimum Factor of Safety against Overturning (Seismic)1.2

Minimum grade of concrete for Plain Concrete BlocksM15

Minimum grade of concrete for Reinforced Concrete BlocksM20

Coefficient of friction (concrete on concrete)0.6

Key Formulas

FS_sliding = (μ * ΣV) / ΣH

FS_overturning = (Σ Resisting Moments) / (Σ Overturning Moments)

Practical Notes

Pay close attention to foundation preparation, as differential settlement can compromise the integrity of the entire block work structure.

Accurate placement of blocks, especially underwater, is critical. Specify tight tolerances and use skilled divers or modern positioning systems (e.g., DGPS).

Interlocking features in blocks (shear keys) are highly recommended to enhance shear resistance between courses and improve overall structural integrity.