IRC Code 83 (Part III)-2018: Standard Specifications for Pot, Pin, Metallic Guide, and Plane Sliding Bearings

‍

The Indian Roads Congress (IRC) provides essential guidelines to standardize road and bridge infrastructure across India. One such critical document is the IRC:83 (Part III)-2018, which focuses on Pot, Pin, Metallic Guide, and Plane Sliding Bearings. These bearings are pivotal in ensuring the durability, safety, and flexibility of bridges, especially in accommodating structural loads, movements, and rotations.

This blog offers an in-depth look into the scope, materials, design principles, and implementation strategies defined by the IRC:83 (Part III)-2018.

‍

‍

Scope of IRC:83 (Part III)-2018

‍

The code specifies the design, materials, manufacturing, testing, installation, and maintenance of the following types of bearings:

1. Pot Bearings: For vertical loads and rotational movements.
2. Pin Bearings: Primarily for horizontal forces and rotation about any axis.
3. Metallic Guide Bearings: To restrict movement along one direction.
4. Plane Sliding Bearings: For unrestricted horizontal movements.

The document is applicable to bearings with operating temperatures ranging from -20°C to 50°C. Bearings designed for extreme tensile loads or rotations beyond 0.03 radians are beyond its scope.

‍

Key Updates in the 2018 Revision

‍

1. Inclusion of Plane Sliding Bearings: Recognizing their utility for unrestricted translational movements.
2. Adoption of the Ultimate Limit State (ULS) Design Approach: Ensuring higher safety and durability.
3. Enhanced Material Standards:
   • High-performance materials like Ultra High Molecular Weight Polyethylene (UHMWPE) for sliding surfaces.
   • Chloroprene Rubber (CR) or Natural Rubber (NR) elastomers for confined pads.
4. Seismic Compliance: Bearings designed to accommodate seismic forces.
5. Rigorous Testing Standards: Mechanical properties, stress-strain relationships, and friction coefficients are now more precisely defined.

‍

Materials for Bearings

‍

1. Steel
   • Mild steel: Grade E350BR (IS:2062).
   • Stainless steel: AISI 316 or 316L for sliding components.
2. Elastomers
   • Confined elastomers (CR/NR) must exhibit high tensile strength, elongation, and tear resistance.
3. Sliding Materials
   • PTFE: Free-sintered with low friction properties.
   • UHMWPE: Superior durability for high-performance sliding.
4. Seals
   • Internal brass or POM seals for pot bearings.
   • External seals made of silicone or chloroprene rubber.

‍

Design Principles

‍

The IRC:83 (Part III)-2018 adopts a ULS-based design approach, focusing on:

1. Load Transfer: Bearings must effectively transfer loads between superstructures and substructures while accommodating rotations and movements.
2. Friction Considerations: Sliding interfaces are optimized for low friction to reduce wear and improve durability.
3. Seismic Design: Ensures the structure's resilience during earthquakes by accounting for dynamic loads.
4. Safety Margins: Incorporates partial safety factors for material properties and load assumptions.

‍

Testing and Certification

‍

To maintain quality, the bearings undergo extensive testing:

• Load Tests: Verify vertical, horizontal, and rotational capacities.
• Material Properties: Tensile strength, elongation, and hardness.
• Durability Checks: Aging, ozone resistance, and compression set tests.

‍

Installation and Maintenance

‍

1. Installation Guidelines
   • Bearings must be installed with proper alignment to ensure functionality.
   • Adequate clearance and anchoring arrangements are vital.
2. Maintenance Protocols
   • Regular inspections for wear and tear.
   • Replacement of sliding components and seals when necessary.

‍

Importance of Compliance

‍

Adhering to the IRC:83 (Part III)-2018 ensures:

• Safety: Prevents structural failures.
• Durability: Prolongs the life of bridges.
• Efficiency: Reduces maintenance costs and ensures smooth functioning under variable loads.

‍

Conclusion

‍

The IRC:83 (Part III)-2018 is a cornerstone for modern bridge design in India, ensuring that bearings are resilient, durable, and compliant with the highest safety standards. By following these guidelines, engineers can create infrastructure capable of withstanding the test of time and dynamic environmental conditions.

‍

RoadVision AI is revolutionizing road infrastructure development and maintenance with its innovative solutions powered by computer vision AI. By leveraging advanced technologies, the platform conducts comprehensive road condition monitoring and traffic surveys, enabling early detection of surface issues like potholes and cracks for timely repairs and enhanced roads. Through traffic congestion analysis, RoadVision AI provides data-driven insights to address traffic congestion challenges and optimize road usage. With a focus on building smarter and more efficient road infrastructure, RoadVision AI ensures full compliance with IRC Codes, helping engineers and stakeholders reduce costs, minimize risks, and improve road safety and transportation efficiency.