Link points to Internet Archive / others. Not hosted by InfraLens. Details
IS 12892:2018 is the Indian Standard (BIS) for pot bearings for bridges - specification. This standard specifies the requirements for materials, design, fabrication, testing, and installation of pot bearings for use in bridges. It covers fixed, free, and guided pot bearings, detailing the properties of steel components, confined elastomer discs, and PTFE sliding surfaces.
Specifies material, design, manufacturing, testing, and acceptance requirements for pot bearings used in bridges.
Overview
Status
Current
Usage level
Specialized
Domain
Structural Engineering — Bridges and Bridge Engineering
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Ensure strict adherence to the surface finish requirements for stainless steel and PTFE mating surfaces to achieve the desired low-friction performance.
! The sealing rings are critical to prevent elastomer extrusion and contamination; their proper seating and material quality must be verified during inspection.
! Installation requires high precision. The bedding mortar level and bearing orientation must be exact as per drawings to avoid inducing unintended stresses in the superstructure and substructure.
EN 1337-5:2005CEN (European Committee for Standardization), Europe
HighCurrent
Structural bearings - Part 5: Pot bearings
Directly equivalent, covering the design, materials, and testing of pot bearings for structures.
AASHTO LRFD Bridge Design Specifications, 9th EditionAASHTO (American Association of State Highway and Transportation Officials), USA
HighCurrent
AASHTO LRFD Bridge Design Specifications (Section 14: Joints and Bearings)
Covers pot bearings within a broader chapter on all bridge bearings, with similar design principles.
BS 5400-9.1:1983BSI (British Standards Institution), UK
MediumWithdrawn
Steel, concrete and composite bridges. Code of practice for design of bearings
Historical predecessor to EN 1337, provided design rules for pot bearings used in the UK.
AS 5100.4:2017Standards Australia, Australia
HighCurrent
Bridge design - Part 4: Bearings and deck joints
Specifies requirements for the design and materials of pot bearings in Australia.
Key Differences
≠IS 12892 mandates specific dimensional checks for sealing rings and piston-to-pot wall clearance, whereas EN 1337-5 focuses more on performance-based requirements verified through testing.
≠The requirements for acceptance testing are more prescriptive in IS 12892, specifying test procedures and loads for 100% of bearings, while AASHTO allows for a combination of prototype and production testing with reduced frequency for the latter.
≠Material specifications in IS 12892 refer exclusively to Indian Standards (e.g., IS 2062 for steel), while international codes reference their respective regional standards (e.g., EN material grades, ASTM specifications).
≠The design verification against uplift or gapping at the edge of the elastomeric pad during rotation is handled differently. IS 12892 provides a simplified check, while EN 1337-5 has a more detailed formula considering the pot wall height and piston diameter.
Key Similarities
≈All standards are based on the same fundamental principle of a confined elastomeric pad deforming to accommodate rotation, with sealing rings preventing extrusion.
≈The primary components—a steel pot, a piston, an elastomeric pad, and metallic sealing rings—are common across all standards.
≈For sliding bearings, the use of a dimpled PTFE sheet sliding against a polished stainless steel plate is a universally accepted mechanism to accommodate translation.
≈The classification of pot bearings into fixed, guided-sliding (uni-directional), and free-sliding (multi-directional) types is consistent across all major standards.
≈The design formulas for calculating the required thickness of the pot wall to resist bursting pressure from the confined elastomer are based on the same thin-wall cylinder theory.
Parameter Comparison
Parameter
IS Value
International
Source
Max. Average Compressive Stress on Elastomer Pad (SLS)
35 MPa
35 MPa (N/mm²)
EN 1337-5:2005
Maximum Design Rotation
± 0.02 radians (default)
Not a prescribed limit; verified by calculation/testing for the project-specific rotation.
EN 1337-5:2005
Max. Average Compressive Stress on PTFE (Total Load)
What is the proof load for testing a pot bearing?+
1.25 times the design vertical load under Serviceability Limit State (SLS) (Clause 8.4.2.1).
What is the specified hardness for the elastomer disc used inside?+
The hardness must be 50 ± 5 IRHD (International Rubber Hardness Degrees) as per Clause 5.2.1 and Table 1.
What is the maximum allowable pressure on the confined elastomer?+
The average pressure on the elastomer under SLS should not exceed 35 MPa (Clause 6.2.2).
What are the key materials used in a pot bearing?+
Structural steel (as per IS 2062), a confined elastomer disc, PTFE sheets for sliding, and austenitic stainless steel for the sliding surface (Clause 5).