Improved In-situ Structural Evaluation Of Historic Buildings Incorporating A 3D Laser Scanning Technique
Free (open access)
C.-J. Chen & T.-C. Wu
A large percentage of historic buildings in Taiwan are of the traditional construction called Chuan-Dou, which consists of posts and mortised beam elements. The walls are usually filled with wattle and daub, and brick or wood planks. Experience has shown that these historic buildings perform moderately well from a strength perspective, but perform with less than good ductility under earthquake waves. Many buildings have collapsed mainly due to material degradation and structural instability. In order to conserve this kind of building, in-situ structural evaluations should be conducted before any renovation or any intervention is done, especially in a seismic-prone area like Taiwan. In general, conventional structural evaluation is based on the analysis of a simplified structural model (i.e., the 2D idealized structural models according to the in-situ survey and drawings). Without considering 3D effects as well as real geometric conditions of structure (e.g., deformation, inclination, etc.), the structural characteristics such as rotational stiffness, displacements, and stress of members are usually underestimated or overestimated. This consequently results in the misjudged restoration or inefficient reinforcement in further interventions. This study proposes a new method incorporating a 3D laser scanning technique, which allows the recording of the real structural geometric conditions, which can be simultaneously converted into 3D models for structural analysis. This improved method increases not only the efficiency of structural evaluation, but also conforms more precisely to the real state of the structure. This paper compares the efficiency and accuracy of structural evaluations between the conventional and the new methods. The measuring technique and the procedure of structural analysis are discussed. Keywords: historic building, laser scanning, structural evaluation.
historic building, laser scanning, structural evaluation.