Fire resistance of epoxied steel rods in glulam timber

Abstract

Timber connections using threaded rods epoxied in glulam timber are becoming more prevalent in use throughout the construction industry and as such their fire resistance must be investigated. The research conducted here was based on finding how strength and stiffness of the cured epoxy was affected by elevated temperatures. Testing was carried out using an oven to simulate heat exposure and with full scale furnace tests. Results show that the epoxies tested lost stiffness at approximately 45 to 55°C. As temperatures rise the strength of the connection becomes less dependent on embedment length and more dependent on the temperature within the epoxy. Steel rods epoxied into the ends of glulam members can achieve a 30 minute fire rating with at least 50 to 60mm timber cover.