Mitigating ancient timber dougong inclination using steel support system: numerical analysis and field monitoring

The dougong (DG) is a key load-bearing component in ancient timber buildings and is susceptible to inclination owing to degradation and environmental loads. This study proposes an external steel reinforcing system to mitigate DG inclination. Using Dacheng Hall as a case study, the effectiveness of the system is examined through numerical analysis and field monitoring. The results indicate that the proposed reinforcement method effectively alleviates the inclination of DGs and improves their stress state. The vertical displacement of each huagong layer can be reduced by 30%–45% and the horizontal displacement by more than 35%. Optimizing the horizontal support dimensions and utilizing square tubes improve performance while reducing weight. Field monitoring confirms that the method significantly decelerates inclination development, with post-reinforcement inclination angles reduced by more than 50%. This study provides a practical method for protecting DGs in ancient timber buildings.