These connections comprise steel rods set into epoxy-filled holes in timber. The rods are placed into oversize holes and the cavity filled with epoxy to enable the epoxy to bond the steel to the timber, thereby enabling the transfer of loads from the timber and into the steel.
These connections allow for the design of aesthetically pleasing high-strength joints.
The technology has been tested in New Zealand and overseas and has been used for around 20 years in New Zealand.
The materials used for epoxy steel rod connections are commonly available in New Zealand, although specific epoxy resins may need to be sourced from wholesalers or manufacturers.
Restriction on use of the epoxy steel rod system in New Zealand is due to designers’ reluctance to specify the product, which in turn is caused by an unfamiliarity and absence of design criteria in the New Zealand Timber Structures Standard NZS 3603.
Glulam dome roof structure for Sydney 2000 Olympics, featuring epoxied steel rod connections
Source: Courtesy Timber Design Guide, 2007