TRAFFIC - Spherical Bearing

1. CLASSIFICATIONS

Spherical bearing is divided into 2 main types:

- Fixed spherical bearing and

- Sliding spherical bearing.

In which, sliding spherical bearing includes guided sliding bearing and free sliding bearing.

2. PRODUCT COMPONENTS

Spherical bearing has a bottom plate (6) on which is a PTFE/UHMWPE curved surfaced sliding plate (4). A convex calotte (5) is placed on top of this PTFE/UHMWPE surface and with hard chrome/stainless steel-plated bottom surface, it can easily slide with low friction, thus facilitating rotations about every axis. A second sliding plate of PTFE/UHMWPE (4) is recessed into the upper surface of the calotte.

Together with the upper plate (2) above it, this accommodates to longitudinal and/or transversally sliding movements of the superstructure, if required. To reduce sliding friction to a minimum, the lower surface of the top plate has a polished stainless steel sheet. In the case of guided bearing, the direction of movement is controlled by guiding bars (3).

The bearing is connected to the superstructure and the substructure by means of anchor dowels (1) (depending on design), or alternatively by means of separate anchor plates with shear studs.

Depending on each type of spherical bearing (fixed, guided or free sliding type), the upper parts are designed accordingly to meet the movement requirements of the bearing.

Spherical bearing transmits tension through vortex calotte surface and evenly distribute the load, including the corresponding force inside concrete structure.

To ensure the long-life durability, Spherical bearings are protected against corrosion by the following methods: two-component Epoxy coat, PU-based painting (Polyurethane), hot dip galvanization according to ASTM A123 standard and especially the Al – Mg spraying method (at the ratio of 95% Al and 5% Mg) which ensure the anti-corrosion durability of up to 100 years, proven by salt-spraying test in 6000 hours (8-hour dry-wet cycle repetition) according to ASTM B117 standard.