IS 4995:1974 is the Indian Standard (BIS) for criteria for design of berthing structures. This standard provides criteria for the design of reinforced concrete bins used for storing granular and powdery materials. It specifies methods for calculating pressures exerted by the stored material using Janssen's theory and provides characteristic properties for various materials. The standard also covers structural design considerations, referencing IS 456 for concrete design.
Specifies criteria for the design of structures for berthing ships, including fender systems and mooring arrangements.
Key reference values — verify against the current code edition / project specification.
| Reference | Value | Clause |
|---|---|---|
| Berthing energy | E = ½·m·v²·Cm·Ce·Cs·Cc (design vessel) | Formula |
| Governing force | Fender reaction at design berthing energy | Critical |
| Mooring | Wind+current on the MOORED vessel → bollard/structure | Loads |
| Combine | + wave/current + seismic-with-hydrodynamics + deck | Loads |
| Durability | Splash/tidal-zone chloride corrosion — co-equal driver | Critical |
| Read with | IS 4651 (ports & harbours) / PIANC / BS 6349 | Cross-ref |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
IS 4995:1974 is the criteria for design of berthing structures — jetties, wharves, piers, dolphins and quay structures where ships moor and berth. It governs the special marine actions (berthing impact, mooring, wave, current) that make port/marine structures fundamentally different from land structures. (The series also covers Part 2 design of derricks/loads etc.; this addresses the berthing-criteria scope.)
It is read with the marine/structural stack:
A berthing structure is dominated by marine actions tied to the design vessel, not building loads:
The key point: the structure is designed for the design vessel's berthing energy and mooring forces in the marine environment, with marine durability as a co-equal design driver.
Scenario: a jetty for a defined design vessel (displacement, approach speed).
Step 1 — design vessel & berthing energy: E = ½ · m · v² · Cm · Ce · Cs · Cc (mass incl. added-mass Cm, eccentricity Ce, softness Cs, berth-configuration Cc) — the energy the fenders must absorb.
Step 2 — fender system: select fenders to absorb E; the fender reaction force at that energy is the governing horizontal design force into the deck/piles.
Step 3 — mooring: compute wind+current on the *moored design vessel* → line forces → bollard/structure design.
Step 4 — combine: berthing (or mooring) horizontal + deck/operational loads + wave/current + seismic-with-hydrodynamics, at the governing water level, into the IS 456/IS 800 design of deck, piles/dolphins and foundation (read with IS 4651).
Step 5 — durability: design the splash/tidal zone for severe marine exposure — high cover, low-permeability concrete, protective systems/CP for steel; durability life is part of the design, not an add-on.
Result: a structure proportioned to the *design-vessel berthing/mooring regime* and built to survive the marine environment for its design life — get the berthing energy or the durability wrong and the jetty fails functionally or by corrosion long before any 'strength' issue.
1. Wrong/optimistic berthing energy. Under-estimating approach speed, added-mass or eccentricity under-sizes the fenders and the design force — the defining berthing-structure error.
2. Designing the structure but not the fender system. The fender governs the horizontal force into the structure; fender selection *is* part of the structural design, not a vendor afterthought.
3. Ignoring mooring (wind/current on the vessel). Bollard/line forces from a moored ship in wind/current can govern — not just berthing impact.
4. Treating marine durability as secondary. Splash/tidal-zone chloride corrosion is the dominant life-limiting action; under-designing cover/concrete/protection fails the structure by durability long before strength.
5. Using land seismic without hydrodynamics / wrong water level. Marine seismic and the governing tidal/water level change the actions materially.
IS 4995 (with the IS 4651 ports-and-harbours series) is the Indian basis for berthing-structure design; on major port projects designers also work to PIANC / BS 6349, which are more developed on berthing-energy and fender design and are compatible when documented. The defining mental model: a berthing structure is governed by the design vessel's berthing energy and mooring forces in a hostile marine environment — its 'loads' come from a ship, not gravity, and its life is set by chloride corrosion in the splash/tidal zone.
The practitioner essentials: nail the design vessel and a realistic berthing energy (approach speed and added-mass are where it goes wrong), design the fender system as part of the structure (the fender reaction is the governing force), include mooring (wind/current on the vessel), combine with wave/current/seismic at the governing water level, and treat marine durability (cover, low-permeability concrete, protection/CP) as a co-equal design driver. Berthing structures rarely fail by under-strength; they fail by under-estimated berthing energy/fendering or by splash-zone corrosion — exactly the two things IS 4995's criteria force you to confront.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Design Philosophy | Working Stress Method (WSM) | Limit State Design (LSD) / Load and Resistance Factor Design (LRFD) | BS 6349-2:2010 |
| Live Load / Surcharge (General Cargo) | 1.0 t/m² (approx. 10 kN/m²) | Typically 20-30 kN/m² (e.g., 25 kN/m² is common) | BS 6349-2:2010 |
| Berthing Velocity (Example: 50,000 DWT, normal conditions) | 15-25 cm/s, based on exposure (Table 1) | Calculated based on charts/formulas considering tug assistance and approach angle; typically 12-18 cm/s. | PIANC Guidelines |
| Hydrodynamic Mass Coefficient (Cm) | Cm = 1 + 2T/B (where T=draft, B=beam) | Formula-based (e.g., Vasco Costa's) or recommended values, typically between 1.4 and 1.8 depending on under-keel clearance. | BS 6349-2:2010 |
| Bollard Capacity (Example: 60,000 DWT vessel) | 100 tonnes (from Table 2) | Derived from calculated wind/current loads; typically in the range of 100-150 tonnes. | UFC 4-152-01 |
| Load Combination with Berthing Load (Accidental) | Permissible stresses may be increased by 25% (WSM) | Load factor on accidental berthing action is 1.0 at Ultimate Limit State (ULS) | BS 6349-2:2010 |