Patterns of Reconstruction at Pompeii
IATH, University of Virginia
1. Objectives and Methods
The study is part of the Pompeii Forum Project (PFP) [Dobbins 1996], whose objective is to document and interpret the urban history of Pompeii, particularly with respect to the Forum. The study focusses on the question of the nature of the reconstruction of the Macellum, a large market building on the north-east corner of the Forum. This building shows signs of extensive damage and repair related to earthquakes, significant because of a large earthquake that struck Pompeii in 62 AD, seventeen years prior to the eruption of Vesuvius that buried the city. The nature of this public building's reconstruction after that earthquake informs the reconstruction of the Forum and the city.
Since the 19th century, the theory concerning the Macellum's reconstruction was that it was incomplete at the time of eruption [Dobbins 1994, p. 669], however in 1994, PFP director John Dobbins proposed a very different scenario, based on close archaeological examination of the Masonry walls. Dobbins concluded that the earthquake was taken as an opportunity for significant civic revitalization, with the Macellum playing an important role in that process [Dobbins 1994, p. 668].
The objective of this study is to test Dobbins hypothesis by examining the evidence from the additional perspective of structural engineering, applying principles of engineering and construction to assess likely reconstruction scenarios. The author of the study is a structural engineer, who has worked with PFP director John Dobbins for a number of years in interpreting damage patterns of Forum buildings, with particular intensity since late 1996, including field visits to Pompeii in 1997 and 1998.
The most important source of information is the ancient masonry itself, and much of the project involves documenting that data. The project employs three fundamental technologies in documenting the masonry construction:
- Digital Imaging: Much of the basic data for the project is based on nearly 600 photographs of Pompeii and the Macellum taken during the summers of 1997 and 1998. These images are organized in a web-accessible database. Manipulated and annotated versions of the image are used in the analysis and explanation. Appendix E includes an online database of Pompeii photographs.
- Digital Photogrammetry: Photogrammetry involves measurements derived from photographs. The project employs the Photomodeler1 program to create three dimensional computer-based models whose coordinates are derived from multiple photographs and whose surfaces are mapped with the photographic images. Appendix A includes a general description of the photogrammetric methods used on the project, as well as the developed models and photographs used.
- Three-dimensional computer models: The photographs and photogrammetric models document the materials and dimensions of the building in its current condition, which includes the effects of damage and aging. At the time of the damaging events, however, the walls were much higher, and there were floors and roofs in parts of the building. Assessing likely damage scenarios requires considering the configuration of the building in its ancient state; Three-dimensional computer models are used in combination with photogrammetric models to describe the likely state of the building at different points in time. Appendix B briefly describes the development of the 3D model.
In applying these analysis methods, the study takes the following steps, each corresponding to a chapter in the text:
- Identify potential damage events, including those since the excavation of the Forum (Chapter 2).
- Identify the types of damage that may result from those events (Chapter 3).
- Review damage areas in the Macellum (Chapter 4).
- Identify configuration and construction characteristics of the building that may influence vulnerability to damage (Chapter 5).
- Review key areas of the building that reveal aspects of chronology (Chapter 6).
- Describe likely scenarios of reconstruction (Chapter 7).
Chapter 2 begins this process, identifying the potential damage events.
Chapter 1 Notes
- EOS, Systems Inc. http://www.photomodeler.com/