IS 4995:1974 Part 1 is the Indian Standard (BIS) for criteria for design of structures for storage of grains - general requirements. This standard provides criteria for the structural design of silos, bins, and bunkers used for the storage of granular materials like grain. It details the methods for calculating lateral and vertical pressures exerted by the stored material on the structure's walls and bottom, distinguishing between deep and shallow bins. The code is primarily based on Janssen's and Rankine's theories for pressure calculation.
Lays down general requirements for the design of structures for storage of grains.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| 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 |