Fire resistance of bolted joints in wooden structures
The results indicate that different mounting variants of screws in a joint play a significant role in the load bearing capacity of fire exposed joints. Mounting the screw head with direct electrical exposure results in a greater loss of fastener length due to wood charring. This further leads to a significantly reduced load bearing capacity after fire exposure.
A countersunk screw with a visible screw head and a protective mandrel is found to be a more suitable installation method to reduce the effects of charring on the screw's fastening length, generating a higher residual load capacity after fire exposure.
The length of the screw is also found to have an impact on the residual load capacity of the joint. The longer the screw, the greater the residual load capacity due to the smaller percentage loss of fastener length. At specific points, the numerical model did not agree with the measured temperatures. However, there is a correlation between wood charring of the test specimens and the temperature distribution obtained from the numerical model in TASEF. This suggests that the model is suitable for predicting the general temperature distribution and wood charring depth inside a fire-prone joint.
Field: Industrial wood construction
Budget: 108,000 SEK
May 2021 - June 2021
Project leader: Peter Jacobsson, Martinsons Byggsystem
Funding: This project is partly funded by TCN.
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