The Structural Effects of Pyroclastic Flow
Mt. Pelée: Construction Types at St. Pierre
Last updated Monday, March 10, 1997, at 2:33 PM Copyright © 1996, 1997 Kirk Martini
Construction Types at St. Pierre
Photographs indicate that much building construction at St. Pierre was unreinforced masonry. The post-eruption overall view and the closer views of damage at Rue Victor Hugo and Rue Lonchamps all show the earmarks of unreinforced masonry construction. Taking a closer look reveals that some buildings used masonry constructions that were similar to the Roman constructions of Pompeii. The image below is an excerpt from the 14 May photo of Rue de Victor Hugo, revealing a thick masonry wall constructed of a core of large stones in a matrix of concrete; this can be seen clearly in the building in the foreground at right, and also in a distant building in the lower left.
| A detail of damaged buildings on Rue Victor Hugo, from the 14 May photo shown above [Heilprin 1903, p. 38]. |
This construction is quite similar to the Roman method of making a wall with a core of rubble and concrete plus a stone or brick facing that served as permanent formwork. The St. Pierre example lacks the stone facing, using removable formwork instead. The Cathedral of St. Pierre, shown below after the May 20 eruption, shows a similar construction of stones and concrete.
| The ruins of the Cathedral of St. Pierre, after the May 20 eruption. [Heilprin 1903, p. 58]. |
As a result of this similarity of construction types, it is probably reasonable to draw general comparisons between damage patterns visible at St. Pierre and those at Pompeii. LaCroix [1908] drew such comparisons, and work is underway to translate LaCroix's writing from the orginal French.
Summary
The 1902 eruptions of Mt. Pelée compellingly demonstrate the destructive potential of pyroclastic surge. The photographs and accounts provide useful information concerning the kinetic energy, temperature and direction of pyroclastic flow and its effect on building structures. To provide a broader view of pyroclastic phenomena and structural behavior, the following discussion examines another well-documented event where structures were subjected to pyroclastic loadings: the 1951 eruption of Mt. Lamington.
| Next: The 1951 eruption of Mt. Lamington |
Last updated Monday, March 10, 1997, at 2:33 PM
Copyright © 1996, 1997 Kirk Martini
Please send comments or questions to Martini@virginia.edu