Simplified Calculation for Fire Performance of Post-Tensioned Timber Box Beams

This paper describes a simplified calculation method that can be used to predict the fire performance of post-tensioned timber box beams. Despite being a combustible material, timber beams can perform well in fire. However, post-tensioned timber box beams need to be carefully designed if an undesirable shear failure mode is to be avoided. A simplified calculation is proposed which can be used to design these beams while giving the designer the ability to predict when and how the beam is likely to fail. Two beam geometries have been used as examples to demonstrate the ability of this calculation method to predict the likely mode and time of failure. Finally, potential improvements that may be made to the method as well as experimental tests that will be conducted to verify the model are discussed.