Ancient Reconstruction of the Pompeii Forum An Investigation of Seismic and Volcanic Structural Response
Part of the Pompeii Forum Project	University of Virginia

Abstract

Table of Contents

• Project Overview
• Acknowledgements
• Viewing Guidelines

• Volcanic History and Phenomena
  • Volcanic Phenomena at Pompeii
  • The Structural Effects of Pyroclastic Flow
    • The 1902 Eruptions of Mt. Pelée
      • Comparing the 8 May and 20 May Eruptions
      • Construction Types at St. Pierre
    • The 1951 Eruption of Mt. Lamington
    • Assessing the Kinetic Energy Potential of Pyroclastic Flow

• Structural Behavior of Unreinforced Masonry
  • Masonry Damage Modes at Pompeii
  • Research in the Out-of-Plane Behavior of Unreinforced Masonry

  • Preliminary ABAQUS Studies
    • Trials
      • A Statically Loaded Column
      • A Dynamically Loaded Column
    • Comparison with Theory
      • The Mendola Study
    • Comparison with Experiment
      • The Yokel Studies
      • The Fattal Studies

  • Empirical Studies of Relative Strength of Two-Way Panels

  • Related Publications
    • Kirk Martini "Finite Element Studies in the Two-Way Out-of-Plane Failure of Unreinforced Masonry," scheduled for publication in Proceedings of the 6th National Conference on Earthquake Engineering, Seattle WA, May 31 - June 4, 1998.
      http://arch.virginia.edu/~km6e/Papers/6-NCEE.pdf (3 MB)

    • Kirk Martini"Ancient Structures and Modern Analysis: Investigating Damage and Reconstruction at Pompeii," Proceedings of the Conference of the Association for Computer-Aided Design in Architecture, Cincinnati OH, October 3 - 5 1997. pp. 283-292.

    • Kirk Martini "Finite Element Studies in the Out-of-Plane Failure of Unreinforced Masonry," Proceedings of the 7th International Conference on Computing in Civil and Building Engineering, Volume 1, Seoul, Korea, August 19 - 21, 1997. pp. 179-184.
      http://arch.virginia.edu/~km6e/Papers/icccbe-7.pdf (128 K)

• Field Observations 1997

  • Database of Photographs

  • The Macellum
    • Area 1
    • Area 2
    • Area 3
    • Area 4
    • Area 5
    • East Wall

• Images of the Macellum

• Bibliography

Project Overview

The following hypothesis was proposed: In 62 AD, seventeen years before the cataclysmic eruption of Vesuvius in 79 AD, there was a major earthquake centered near Pompeii, causing significant damage. Early Pompeii scholars reasoned that while private landowners and merchants had the resources to repair their structures, the Pompeiian government was unable to rebuild the Forum. The city's economy was depressed, there was no assistance from the central government in Rome, so the buildings composing the civic center lay in disrepair during the seventeen year interval between the earthquake of 62 and the eruption of 79.

That view was widely accepted and remained part of archaeology's common wisdom for more than 150 years; however, in recent years a different view has emerged. Dobbins [1994; 1994a] has put forth the hypothesis that the earthquake was used as an opportunity to reshape the Forum, including realigning streets, uniting building fronts and adding a new building based on the latest designs from Rome. The conclusions are based on "reading" the masonry walls, that is, closely examining the patchwork of materials and construction techniques that compose the walls and drawing conclusions about the sequence and timing of construction with respect to the earthquake, the volcanic eruption, and the excavation.

Working as part of the Pompeii Forum Project [Dobbins 1996], the current study aims to bring a new kind of light to the task of reading the masonry walls: the light of engineering analysis. Although many questions can be addressed using archaeological evidence, such as the presence of ancient plaster and the application of certain construction techniques, there are other questions that can be addressed much more directly by considering the structural response to volcanic and structural phenomena. Structural analysis is not likely to offer definitive answers, since there are many unknown factors, but it will be able to test the validity of current hypotheses, either confirming with additional evidence or challenging and pointing the way to revised hypotheses.

The study has the following objectives:

• Explain the fundamental response modes of masonry walls to seismic and volcanic events.

• Gather data and draw conclusions concerning the effects of pyroclastic flow on structures. There has been very little study of this phenomenon, since it rare for structures to be subjected to pyroclastic flow. The study will focus on the 1902 eruption of Mt. Pelée in Martinique [La Croix 1904; Heilprin 1903; Fisher 1982], and the 1951 eruption of Mt. Lamington in Papua New Guinea [Taylor 1958], both of which bear some resemblance to circumstances at Pompeii.

• Analyze selected portions of the Macellum, a major market building on the Forum, for forces induced by earthquakes and by pyroclastic flow to see whether the response is compatible with Dobbins' hypothesis that the Macellum experienced major damage in the earthquake, and relatively minor damage (which can be seen today) resulting from volcanic phenomena. The analyses will incorporate site-collected data concerning the properties of the materials composing the walls and the spatial dimensions, and employ the ABAQUS program [HKS 1996] for non-linear dynamic structural analysis.

The seismic analysis will incorporate ground motion records from nearby locations in Italy, extracted from the Strong Motion Data collection of the National Geophysical Data Center [NGDC 1996]. The pyroclastic flow analysis will test a range of simplified load conditions, based on upper and lower bounds established by phenomena observed at Mt. Pelée, Mt. Lamington, and other relevant pyroclastic events, and on numeric simulations of pyroclastic flow at Vesuvius by Dobran [1994, 1996].

Acknowledgements

• The Dean's Forum of the School of Architecture at the University of Virginia
• The National Endowment for the Humanities.
• The University of Virginia Sesquicentennial Associateship Program.
• The IBM Shared University Resource (SUR) Program.
• The Pittsburgh Supercomputing Center.

This support is gratefully acknowledged.

The ideas underlying this investigation have been developed over a series of discussions that have included John Dobbins, Tom Baber of the Department of Civil Engineering, and Tanya Furman of the Department of Environmental Sciences. James B. Heidel has provided invaluable assistance in collecting, reviewing, and organizing background materials. Their contributions along with those of the interdisciplinary team composing the Pompeii Forum Project have been essential in the conception and initiation of this project.