The fire performance of moment-resisting nailed connections between heavy glulam timber members

The fire performance of moment-resisting nailed connections between heavy glulam timber members is investigated. For protected steel and ply­ wood gusseted joints, the time-temperature results achieved during a standard fire test (ISO 834) are simulated. The joints are loaded during this simulation to determine the load-deformation characteristics of the nails. Using these load-deformation relationships as input information to a computer model, the moment-rotation characteristics of these joints are computed. The application of the model to predict the fire performance of nailed joints, tested under full exposure is shown. Further application is indicated by analysing a knee joint of a portal frame. The temperature development along the length of the nails in these joints is also observed. Nailed gusseted connections between glulam members have good fire performance when protected by gypsum plaster board. The nail temperatures in protected joints are too low to cause any serious undesirable effects on joint performance. The application of the computer model to predict the fire performance of nailed gusseted connections tested under full exposure has shown good correlation with test results. Calculations show that the deflections of the protected knee and apex joints of a typical portal frame are small and the frame as a whole has very good fire resistance