Laser scanning techniques and safety analysis for Nantou city wall

Structural engineers may utilize geometric techniques for precise and accurate measurements of discrete points, detailed façade recording, and the productions of engineering drawings and plans. An introduction to laser scanning is given, followed by details of one test on the Natou city wall in Shenzhen, China, one of the important military towns in the frontier. The aim of this paper is to analyze the static behavior of city wall under different material conditions, normal condition and unfavorable condition. A 3D survey of the wall was carried out by means of a 3D laser scanner which allowed the acquisition of the metric data of the external surface in terms of point clouds. These were then processed and transformed in to a suitable 3D model on which mechanical analysis was performed within a finite element method. Results show that the water penetration towards the core soil has reduced the mechanical performance.