Fosroc Spherical Bearings
Project-engineered PTFE spherical bearings that absorb vertical and horizontal loads while accommodating large multi-directional rotations on long-span and seismically active bridges.
What is it?
A bespoke structural bridge bearing built from a steel pot with a spherical cap, PTFE sliding sheets and a steel lid, designed to carry heavy vertical and horizontal loads while permitting large rotations in every direction.
Where is it used?
Long-span, continuous, cable-stayed and suspension bridges, elevated metro and highway viaducts, and seismically active structures across India where high rotation and movement capacity are required.
Why use it?
It accommodates much larger and more uniform rotations than elastomeric or pot bearings, with low PTFE friction, high load capacity and long service life – ideal where rotation demand is the governing design factor.
How is it applied?
Each unit is engineered, manufactured and tested to project loads, then installed between the pier/abutment and the superstructure, typically bedded on Fosroc Conbextra grouts and fixed via anchor assemblies as a fixed, free-sliding or guided type.
About Fosroc Spherical Bearings
Fosroc Spherical Bearings are precision structural bearings used at the interface between a bridge superstructure and its supporting piers or abutments. According to Fosroc’s official product literature, the bearing is built from a steel pot fitted with a spherical (concave) cap, PTFE sliding sheets and a steel lid, with the spherical cap fully contained within the pot through interposition between the pot and the lid. The defining feature is the curved, spherically-machined sliding surface: rotation is achieved by one steel element sliding over the matching concave surface across a low-friction PTFE interface, rather than by deforming an elastomer or compressing a confined rubber disc as in elastomeric or pot bearings.
In service the bearing performs three jobs simultaneously. It absorbs stresses from vertical and horizontal loads, it accommodates rotations and horizontal displacements, and it allows the deck to move freely under temperature change, creep, shrinkage and seismic action. Fosroc describes the assembly as behaving such that the pot acts like an incompressible fluid, enabling the lid to oscillate relative to the pot while hydrostatic pressure is released – the mechanism that lets a spherical bearing rotate about any horizontal axis without locking up.
A central point that Space Arc Engineering emphasises to specifiers is that Fosroc Spherical Bearings are not a catalogue item with fixed sizes. Fosroc states each bearing is bespoke to the specific project, meeting the desired design requirements. Vertical load, rotation angle, horizontal movement, friction and overall geometry are all engineered to the bridge in question and then verified by testing. For Indian projects the governing reference is IRC:83 (Part IV)-2014, which deals specifically with spherical and cylindrical bearings – covering material requirements, design, manufacturing, testing and installation over the standard operating temperature band of roughly -15 deg C to 50 deg C. Internationally the equivalent product standard is BS EN 1337-7 for spherical and cylindrical PTFE bearings. Because design values are project-derived, this page deliberately does not publish fixed numerical capacities; those are confirmed on the project-specific technical data sheet and shop drawings.
As an authorised Fosroc distributor serving Delhi NCR and Pan-India, Space Arc Engineering supports consultants and contractors with bearing selection, schedule preparation, the matching Fosroc grouting and anchoring systems, and coordinated delivery to site.
The technical insight
The engineering value of a spherical bearing lies in how it separates rotation from translation. The concave/convex spherical PTFE interface lets the structure rotate about any horizontal axis with a near-constant, low resisting moment, because rotation simply slides PTFE over a curved stainless surface – unlike an elastomeric pot bearing, where the confined rubber generates a restoring moment that grows with rotation. This makes spherical bearings the preferred choice when rotation demand is high or repetitive, as on long continuous spans, cable-stayed and suspension decks, or curved alignments. A second, flat PTFE/stainless sliding plane is added on top of the rotational element to create a free-sliding (multidirectional) or guided (unidirectional) bearing; omitting it gives a fixed bearing that takes load and rotation but no translation. PTFE friction is low (typically only a few percent and load- and temperature-dependent), and lubrication dimples plus the curved geometry keep the rotational resistance small even under heavy axial load. Indian practice under IRC:83 Part IV recognises PTFE-based service life of the order of 30 years, with UHMWPE sliding materials offering longer life – a useful lever when whole-life cost and inspection access are part of the brief.
Where it is used
- Long-span and continuous girder bridges where rotation at supports is large or repetitive
- Cable-stayed and suspension bridges with significant deck rotation and translation under live and wind load
- Elevated metro viaducts and flyovers in Delhi NCR and other metropolitan corridors
- Highway and expressway bridges on curved or skewed alignments
- Seismic zones where the bearing must release thermal and earthquake-induced movement
- High-load piers and abutments where compact, high-capacity bearings are needed in limited space
- Heavy industrial and crane structures requiring controlled rotation under concentrated loads
Key advantages
- Accommodates large, multi-directional rotations with low, near-constant resisting moment – superior to elastomeric and pot bearings for high-rotation demand
- Carries high vertical and horizontal loads in a relatively compact footprint
- Low-friction PTFE sliding interface reduces force transmitted to piers and substructure
- Available as fixed, free-sliding (multidirectional) or guided (unidirectional) types to suit the articulation scheme
- High durability and long service life – PTFE service life of the order of 30 years under IRC:83 Part IV, longer with UHMWPE
- Bespoke design and testing to project loads, ensuring code compliance under IRC:83 (Part IV) / EN 1337-7
- Releases movements from temperature, creep, shrinkage and seismic action, protecting the superstructure
Limitations & considerations
- Not an off-the-shelf product – each unit is project-engineered, so lead time and design coordination are required
- Fosroc’s published literature does not list fixed numerical capacities; load, rotation and movement values must be confirmed on the project-specific data sheet and drawings
- Correct installation is critical – level bedding (typically on Fosroc Conbextra grout), accurate anchoring and pre-set offsets must be respected
- PTFE friction and capacity are temperature- and load-dependent, so design assumptions must match site conditions
- Sliding surfaces require protection from grit and contamination during construction; damaged PTFE compromises performance
- Inspection and eventual bearing replacement provisions should be designed in, as PTFE has a finite service life
- Higher unit cost than elastomeric bearings – justified only where rotation or load demand genuinely requires it
Selection & best practice
Specify Fosroc Spherical Bearings only where rotation or load demand genuinely exceeds what an elastomeric or pot bearing can serve, and engage the supplier early so each unit is engineered and tested to the project’s vertical load, rotation and movement schedule under IRC:83 (Part IV)-2014. Define the articulation clearly – which supports are fixed, free-sliding (multidirectional) or guided (unidirectional) – before finalising the schedule. At installation, set the bearing dead level on a sound bedding (typically a Fosroc Conbextra cementitious or epoxy grout), respect any temperature pre-set offset, keep the PTFE and stainless surfaces clean and protected until commissioning, and never weld or apply heat near the bearing. Retain the project-specific technical data sheet, test certificates and as-installed records, and design in safe access for future inspection and replacement.
Specifications
| Product type | Spherical bridge bearing (PTFE sliding type) |
| Core composition | Steel pot with spherical cap, PTFE sliding sheets and steel lid (per Fosroc literature) |
| Rotational mechanism | Curved spherical PTFE/stainless interface; rotation about any horizontal axis |
| Available types | Fixed, free-sliding (multidirectional), guided (unidirectional) |
| Loads accommodated | Vertical and horizontal loads; rotations and horizontal displacements |
| Movements released | Temperature, creep, shrinkage and seismic (earthquake) movements |
| Governing standard (India) | IRC:83 (Part IV)-2014 – spherical and cylindrical bearings |
| International standard | BS EN 1337-7 (spherical and cylindrical PTFE bearings) |
| Operating temperature (IRC context) | Approx. -15 deg C to 50 deg C |
| Indicative PTFE service life | Order of 30 years (PTFE); longer with UHMWPE – per IRC:83 Part IV |
| Load / rotation / movement capacity | Project-specific – bespoke per design; confirmed on project data sheet |
| Durability | High (manufacturer-stated) |
Industry use cases
Metro & urban transit
Elevated metro viaducts in Delhi NCR and other cities use spherical bearings at piers to accommodate deck rotation and thermal movement on long, repetitive precast spans.
National highways & expressways
Long-span and continuous highway bridges on curved or skewed alignments rely on spherical bearings where rotation at supports exceeds elastomeric bearing capacity.
Major / signature bridges
Cable-stayed and suspension bridges with large, repetitive deck rotation and translation under live and wind loads use spherical bearings for their high rotation capacity.
Seismic-zone infrastructure
Bridges in higher seismic zones use fixed and sliding spherical bearings to release earthquake-induced and thermal movements while keeping the deck stable.
Heavy industrial structures
High-load industrial gantries and crane-supporting structures use spherical bearings where concentrated loads and controlled rotation must be managed in a compact unit.
Frequently asked questions
What are Fosroc Spherical Bearings made of?
How is a spherical bearing different from a pot bearing or an elastomeric bearing?
Which standards govern Fosroc Spherical Bearings in India?
What load and rotation capacity does a Fosroc Spherical Bearing have?
Can the bearing be fixed, free-sliding or guided?
Does Space Arc Engineering supply Fosroc Spherical Bearings across India?
How we position Fosroc Spherical Bearings
Fosroc Spherical Bearings sit at the high-rotation end of Fosroc’s bearing range. Within the Fosroc portfolio they complement Fosroc Pot Bearings (compact high-load bearings for moderate rotation) and Fosroc Elastomeric Bearings (economical for shorter spans and smaller movements), and pair naturally with Fosroc expansion joints and the Conbextra grout range for bedding and anchoring – all available through Space Arc Engineering. Choose spherical bearings when rotation demand is the governing factor; choose pot or elastomeric bearings when it is not, to control cost. Against the wider market, comparable spherical/PTFE bridge bearings are offered in India by specialist bearing manufacturers, and adjacent waterproofing, grouting and joint products are available from Sika, Dr. Fixit (Pidilite), STP and MBCC/Master Builders Solutions (MBS); honest comparison on these systems is something Space Arc is happy to provide so specifiers can match the bearing and its bedding/sealing system to the project rather than to a single brand.
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