Spherical Bridge Bearing – QZ Series for High Load, Large Rotation & Multi-Directional Movement

Our spherical bridge bearing (also known as spherical bearing or QZ series spherical bearing) is an advanced structural support device designed for bridges requiring high load capacity, large rotation angles, and reliable performance in all directions. Unlike pot bearings, spherical bearings use a convex intermediate plate with a PTFE spherical surface to achieve rotation, eliminating rubber aging issues and providing consistent rotational resistance regardless of angle.

What is a Spherical Bearing?

A spherical bearing consists of an upper bearing plate, a lower bearing plate, a convex intermediate plate, and two PTFE plates of different shapes. The lower plate features a concave spherical surface that matches the convex intermediate plate. A curved PTFE plate between them allows smooth rotation of the beam end. A second sliding surface (stainless steel + PTFE) accommodates horizontal displacement caused by temperature changes and other factors.

Spherical bearings ensure reliable force transmission and consistent rotational performance in all directions. They inherit the advantages of pot bearings (high load capacity, large horizontal displacement) while also meeting the requirements of large rotation angles, making them ideal for wide bridges and curved bridges. Since no rubber components are used for load transmission, problems such as low-temperature rubber brittleness are eliminated – especially suitable for cold regions.

Key Advantages Over Pot Bearings

• No stress concentration – Force is transmitted through the spherical surface, resulting in uniform reaction on concrete.
• Low and angle‑independent rotational moment – Rotation depends only on spherical radius and PTFE friction coefficient, not on rotation angle. Design rotation angle up to 0.05 rad or more.
• Consistent rotation in all directions – Perfect for wide bridges, curved bridges, and skew bridges.
• No rubber aging – Ideal for low‑temperature regions and long service life without performance degradation.

Types of Spherical Bearings – QZ Series

According to GB/T 17955 standard, our QZ series spherical bearings are available in three movement types:

• Fixed Spherical Bearing (GD) – Allows rotation only, no horizontal displacement.
• Unidirectional Sliding Spherical Bearing (DX) – Allows rotation and guided displacement parallel to the bridge axis (or a specified direction).
• Bidirectional Sliding Spherical Bearing (SX) – Allows rotation and free displacement in any horizontal direction.

We also manufacture other series upon request: KLQZ, QZ(09T), JQZ (Type I/II/III), GQZ, LQZ, CGOZ, XQZ, LSQZ, etc.

Technical Specifications – QZ Series Spherical Bearings

1. Vertical Load Capacity (Reaction Force)

Available in 29 grades from 1500 kN up to 60,000 kN: 1500, 2000, 2500, 3000, 3500, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 12500, 15000, 17500, 20000, 22500, 25000, 27500, 30000, 32500, 35000, 37500, 40000, 45000, 50000, 55000, 60000 kN.

2. Design Rotation Angle (θ)

Available grades: 0.02, 0.03, 0.04, 0.05, and 0.06 rad. Custom angles available.

3. Design Horizontal Displacement

• Longitudinal displacement: For 1000‑2500 kN: ±50 mm, ±100 mm. For 3000‑10000 kN: ±50 mm, ±100 mm, ±150 mm.
• Transverse displacement (for SX type): ±20 mm standard.
• Custom displacement ranges available upon request.

4. Friction Coefficient (with silicone grease lubrication, stress ~30 MPa)

• Normal temperature (-25°C to +60°C): ≤0.03
• Low temperature (-40°C to +60°C): ≤0.05

5. Horizontal Force Capacity

• Unidirectional sliding bearing (DX): Transverse horizontal force = 10% of vertical reaction force.
• Fixed bearing (GD): Horizontal force capacity = 10% of vertical reaction force.

Installation Guide for QZ Spherical Bearings

1. Concrete grade: Bridge girder and pier support areas must use concrete grade not lower than C35.
2. Leveling: Use copper wedges at four corners of the lower plate to level the bearing. The bottom of lower plate should be 20‑50 mm above pier top surface.
3. Grouting: Fill anchor bolt holes and bedding layer with epoxy mortar (example mix ratio available in our manual).
4. Welding option: If welded connection is used, apply intermittent welding to embedded steel plates. Avoid damaging bearing or concrete.
5. Installation height tolerance: Height difference at four corners of bearing support surface ≤ 2 mm.
6. Remove connecting plates: After girder installation, remove upper and lower connecting plates to avoid restraining normal rotation. Then install rubber dust seals for sliding bearings.
7. Preset displacement/rotation: Bearings can be factory‑preset with rotation angles and displacements if specified when ordering.

Maintenance Recommendations

• Perform annual comprehensive inspection.
• Check anchor bolts for shearing; inspect rubber seals for cracking or aging.
• Verify relative displacement uniformity and record positions.
• Remove debris and clean stainless steel surfaces with cotton yarn.
• Loosen anchor nuts once per year, clean and oil to prevent rust seizure, then retighten.
• Monitor bearing height changes. If height reduction exceeds 3 mm, inspect PTFE plate condition.
• Regularly apply anti‑rust paint to steel components (excluding stainless steel sliding surfaces).

Why Choose Guchen Spherical Bearings?

As a professional spherical bearing manufacturer and supplier with over 15 years of experience, we offer:

• Engineering excellence: In‑house FEA analysis, custom designs per project requirements.
• Strict quality control: High‑grade materials, compliance with EN, AASHTO, DIN, and GB/T 17955.
• Global track record: Supplied to 30+ projects worldwide including wide bridges, curved bridges, skybridges, and space frames.
• Total support: Technical documentation, installation guidance, after‑sales support.

📞 Get a quote for spherical bearings – Send us your project parameters (load, rotation angle, displacement, type) and we will reply within 24 hours.