Cable-restraining bearing (CRB)

Cable-restraining Bearing (CRB) was invented by the late Prof. Yuan Wancheng at Tongji University in the early 2010’s and now extensively utilized across China during the selection of proper anti-seismic bearings for bridges. IEC contributed notably to the standardization and commercialization of CRB in Chinese market.

Basically, CRB is to add the steel cables/strands to the conventional bearings, a pot bearing or spherical bearing, to prevent the excessive displacement within the design range during a seismic event.

During normal service, CRB functions no differently with common types of pot bearings or spherical bearings. Under small to medium levels of earthquakes, cables slide to dissipate quake energy and the shear pin (bolt) is not supposed to break off so replacement of bearings are not needed. When rarely high level earthquake takes place, shear pins are designed to break off so the bearings work as a system to become sliding bearings. The cables sway to mitigate the quake effect so to protect the bridge girder from excessive displacement. This is to prevent the girder from risks of falling-off during heavy earthquake.

The combination of functions of cable-sliding design with conventional bearing enables CRB to be featured with excellent seismic-prevention during earthquake while functional as normal bearing during service.

                                                    Section view (typical design)                                                                                                               Cut-away view of CRB

CRB in service, supplied by IEC in Mianyang Bridge, Sichuan 2017

CRB for installation for Chaotianmeng Bridge, Beijing in 2018

Consult IEC engineers for details.