Standards for bearings, joints and couplers on resource road bridges


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Guidance for bridge bearings, joints and couplers


Bearings

Bearings shall be ozone resisting natural rubber (natural polyisoprene) designed in accordance with CHBDC.

Bearings must be protected against water ponding and accumulation of debris.

Steel reinforced elastomeric bearings shall have a minimum of two steel reinforcing plates and the cover of elastomer for the top and bottom plates shall be 5 mm. Side cover on all reinforcing plates shall be 5 mm.

Detailed specifications for bearing design and fabrication can be found in this document: Design of Bearings for Typical Steel Girder Forestry Bridges (Associated Eng, 2004, PDF 270 KB)


Joints

Most single span Ministry bridges are of a semi-integral design where expansion/contraction deck joints are not required at the bridge ends.  Long span bridges shall utilize expansion/contraction joints if the thermal expansion/contraction is excessive for use of the typical semi-integral system.

For multi-span bridges the joint design between spans shall be proposed by the general arrangement engineer or structural design engineer for approval consideration by the Ministry engineer.
All joints shall be designed to ensure that leakage detrimental to the structure (e.g. onto bearings below) does not occur.

Notwithstanding the above, typical joints between concrete deck panels, timber deck panels and concrete slab girders shall be in accordance with the standard drawings. 


Couplers

Couplers shall conform to ASTM A563 Grade A minimum tensile strength of 120% of the yield strength of the elements being connected, unless otherwise specified by the Ministry.