Application of Digital Close-Range Photogrammetry to the Modeling of Heritage Structural Elements for Its Analysis by FEM

Abstract

The modeling of structural elements with complex geometries requires a lot of field and office work, even more so when these elements belong to heritage buildings, which usually have geometric damage caused by natural and anthropogenic weathering; damage to these elements are difficult to record and characterize, and even more difficult to model. However, since the accuracy of the results in modeling and numerical analysis of heritage structural elements by FEM largely depends on the quality of the model in terms of its geometry, the implementation of techniques is required, which results in fast, cheap and reliable modeling; allowing, in addition, the representation of the geometric complexity of the item, measuring and feeding the simulation with deterioration data. The modeling of structural elements, on heritage buildings by implementing digital close-range photogrammetry techniques allows a very good geometrical precision, which is almost impossible to obtain with conventional techniques of manual survey; on the other hand, while using techniques such as laser scanner allows to gather high quality information, on developing countries this equipment is unaffordable. One of the great advantages of the implementation of photogrammetry is the low cost of the equipment and software required; in addition, it only requires minimal staff training and a very basic knowledge in photography, allowing the integration of many people from different disciplines and academic backgrounds into the modeling work. This work shows the results of contrast structural evaluation of damaged stone elements modeled and analyzed using FEM with traditional techniques, and those modeled with photogrammetry techniques, comparing work times and accuracy results.