Issue 53

D. Wang et alii, Frattura ed Integrità Strutturale, 53 (2020) 236-251; DOI: 10.3221/IGF-ESIS.53.20 243 Figure 10: Crack distribution in the thickness direction on the long sides of the plate. (a) S1 (b) S2 (c) S3 Figure 11: Crack distribution on the top of the plate. (a) 20min after ignition (b) 30min after ignition (c) 45min after ignition (d) 75min after ignition (e) 120min after ignition (f) 210min after ignition (flameout) Figure 12: Crack development on the top of the plate of S3 under fire. Crack development on plate surface under fire In the fire test, the plate surface was covered by lots of water stains and water vapor, making it difficult to observe crack distribution and development with the naked eye. To overcome the difficulty, infrared detection technology was introduced to monitor the plate crack development. For the lack of space, this paper only provides the crack development of S3 in six stages after ignition, which was captured by our infrared thermal monitoring device (Fig. 12). The crack development in plate-column was not captured, for the device was installed directly above the specimen (i.e. the central nodes were blocked by the loading beams and distribution beams).