An experimental study of the damage degrees to ancient building timber caused by lightning strikes

Lightning strikes are one of the main natural causes of damages to ancient buildings, and have attracted a great deal of attention to the problem of lightning strike disasters. In this study, the lightning strike damage mechanism of ancient building timber and the related damage degrees are investigated, based on the representative timber materials. A lightning-strike simulation device with a 10/350 μs lightning current waveform was adopted for the experiments. The experimental results showed that the lightning strike damages to ancient building timber mainly included timber heating caused by lightning arc heat and current, as well as the air shock wave effects of the lightning, which led to various effect modes under different conditions. The correlations between the damage degree of timber and the water content of timber, timber thickness, as well as the lightning current intensity, are obtained. The current peaks of lightning and the timber water content are the main external and internal causes which influence the damage degrees of ancient timber.