PSI - Issue 64

D.B. Zhang et al. / Procedia Structural Integrity 64 (2024) 1997–2004 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

2002 6

Fig. 2. Infrared thermal imaging of hollowing regions of east facing facade (a) region A; (b) region B; (c) region C.

6. Identification of falling-off hazards for external thermal insulation system of inorganic thermal insulation mortar 6.1. Construction project profile and testing region of external wall A 12-story residential building in a community in Shanghai was completed in 2012. The building walls had adopted the external thermal insulation system of inorganic thermal insulation mortar. After being delivered for use, the external thermal insulation system of many buildings appeared hollowing and cracking continuously, posing a high risk of falling-off hazards. Selecting the east facing facade of Building 97 as the research object, as shown in Fig. 3(a), there exists a large continuous hollowing defect on the external wall between the 6th and 7th floors. To monitor the variation character of the hollowing defect over time, four fixed targets were set, followed by the regular collection of point cloud data from the east facing facade using 3D laser scanner.

Fig. 3. East facing facade model of external wall (a) photo; (b) flatness; (c) contour; (d) local detail.

The point cloud data is densely and disorderly arranged. Before creating a contour map, the point cloud data is firstly classified by a classification algorithm based on the model to extract the necessary point cloud data. Next, the dense point cloud data is thinned to prevent contour lines from being fragmented and wrinkled due to excessive point