Introduction
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Cambridge University Press 0521842026 - Concrete Vaulted Construction in Imperial Rome: Innovations in Context Lynne C. Lancaster Excerpt More information 1 INTRODUCTION oncrete vaulted structures represent one ploit the fireproof nature of concrete and in doing so C of the ancient Romans’ most original and en- created a new aesthetic based on the plastic potential during contributions to the artistic and architectural inherent in the material.1 In imperial Rome, all of patrimony of the Mediterranean world. A combina- the natural advantages and cultural influences came tion of factors led to the development of the large together and manifested themselves in imposing con- spans and curvilinear forms still visible in buildings crete vaulted structures, the remains of which are the such as the Pantheon and the Basilica of Maxentius. focus of this study. Rome was endowed with a wealth of natural re- My intention is to examine the changes that oc- sources in its immediate environs, and what it could curred in the choice of materials and techniques used not supply for itself it could bring in from afar through in concrete vaulted construction in Rome from the the development of extensive trade networks. Along time of Augustus to Constantine and to place the re- with the financial benefits of conquest came the ar- sults in the wider social, economic, and political con- chitectural, technological, and mathematical exper- text. I document the appearances of particular mate- tise of the architects, builders, and engineers from the rials and building techniques and examine the reasons conquered territories. Augustus, in bringing the civil for their use and the ways that use changed over time. wars to an end, also brought a vision of urban renewal In particular, I am interested in techniques that aided for Rome that provided incentive for more grandiose in the creation of large and complex structures, such as schemes than had previously been possible. By that the use of lightweight concrete, brick vaulting ribs, time, the architects and builders had over a century metal tie bars, and various forms of buttressing. In of collective experience with concrete construction, some cases, the choices of the builders were affected but Augustus’s creation of an organizational infras- by external factors such as the availability and the cost tructure provided a context in which new ideas and of materials or the changes in the infrastructure of the larger building schemes were possible. As emphasized building industry itself. The interplay between the by W. L. MacDonald, the fire that devastated much decisions made on the building site and these exter- of Rome during Nero’s reign in a.d. 64 effectively nal factors can create a window into the complexities cleared the slate and provided opportunities to ex- of urban and suburban life in Rome. 1 © Cambridge University Press www.cambridge.org Cambridge University Press 0521842026 - Concrete Vaulted Construction in Imperial Rome: Innovations in Context Lynne C. Lancaster Excerpt More information CONCRETE VAULTED CONSTRUCTION IN IMPERIAL ROME a note on monuments and previous combining my own on-site observations with those scholarship of others to create an overview of the developments. This would not be possible without the publica- The monuments included in this study date from the tion of monographs during the past few decades by reign of Augustus (27 b.c.), when the resources of scholars conducting fieldwork on some of the major the Mediterranean basin became widely available in monuments in Rome: K. de Fine Licht on the Rome, to the reign of Constantine, when patron- Pantheon (1968), the Baths of Trajan (1974), and Sette age was diverted to the new capital inaugurated at Sale (1990); C. M. Amici on the Forum of Trajan Constantinople (a.d. 330). The monuments are for (1982) and the Forum of Caesar (1991); J. E. Packer the most part limited to buildings in the city of on the Forum of Trajan (1997); J. DeLaine on the Rome and its immediate environs because I am par- Baths of Caracalla (1997); and J. J. Rasch on a se- ticularly concerned with the local materials and the ries of late Roman domed structures including the economic, social, and political factors unique to the Tor de’Schiavi (1993) and the Mausoleum of Helena capital city. Many of them are state-sponsored public (1998). The engineering works of J. Heyman (1995, monuments, such as the imperial thermae, basilicas, 1996) and R. Mark (1982, 1990) have been par- and places of public spectacles like theaters and am- ticularly influential in my approach to the struc- phitheaters. Some are imperial residential structures tural aspects of vaulting. I also have drawn on such as the palaces on the Palatine, the domed pavil- numerous articles by archaeologists, geologists, and ion in the Horti Sallustiani, or the nymphaeum in engineer/architects working in Rome as well as on the Horti Liciniani (“Temple of Minerva Medica”). the invaluable resource of E. M. Steinby’s Lexicon To- Some structures in the immediate outskirts of Rome pographicum urbis Romae (1993–2000). Although the also are included, such as the Villa alla Vignaccia, study is in the spirit of previous works on Roman the Villa di Sette Bassi, and the so-called Villa of the construction such as those by M. E. Blake (1947, Gordians. Further afield are two imperial villas, 1959, 1973), G. Lugli (1957), J.-P. Adam (1994), and Domitian’s Villa in the Alban hills and Hadrian’s Villa C. F. Giuliani (1990), my focus is narrower and my near Tivoli, both of which demonstrated innovative inquiry delves deeper into specific issues relating to vaulting techniques that relate to developments in the construction of large-scale concrete vaulting. Rome itself. During the early fourth century, domed mausolea often located on suburban villas became popular, and these extramural structures are also ex- how to use this book amined. One monument important to this study is located outside of the immediate environs of Rome. The book is organized so that it can be used by both The structure, known as the “Temple of Mercury” at general readers and specialists. The material in the Baiae on the Bay of Naples, is both the earliest pre- remaining sections of this chapter and in the final served concrete dome and the largest spanned dome chapter (“Innovations in Context”) is intended to before the Pantheon and hence must be considered in provide general discussions accessible to a wide au- any discussion of the development of concrete vaults. dience. Each of the other chapters is provided with a One goal of the present work is to provide a syn- brief introduction to the major issues and a conclu- thetic study of the concrete vaulting in Rome by sion that includes a broader overview and assessment 2 © Cambridge University Press www.cambridge.org Cambridge University Press 0521842026 - Concrete Vaulted Construction in Imperial Rome: Innovations in Context Lynne C. Lancaster Excerpt More information INTRODUCTION of the material discussed within the chapter. A gen- concrete were laid separately, by hand and trowel. eral reader can read the first and last chapters of the In both ancient and modern concrete construction, book as well as the beginning and end of each chap- some type of structure, or centering, is necessary to ter to get an idea of the issues discussed and their contain and model the wet mortar until it sets and relevance, whereas the specialist can delve into the gains strength. details of the arguments presented within the chap- The mortar of the Romans was stronger than the ters. I also have provided catalogues in Appendix 2 earlier mortar used in Greek architecture because of listing all of the documented examples of a particular the addition of a local volcanic material called poz- technique, many of which are not discussed in the zolana, which creates a chemical reaction that results text. For those who want to pursue the subject fur- in a mortar much more tenacious than simple lime ther, these tables provide detailed information about mortar. Furthermore, pozzolana mortar is hydraulic every entry along with bibliographic references. In and sets underwater. Mortared construction was used addition, I have included in Appendix 1 a catalogue outside of Rome and Italy, but locally available ingre- of the main monuments discussed in the text and a dients were often substituted. Because each ingredient map with their locations (Map 1,p.4). For readers has a unique effect on the final mixture, distinguish- not familiar with a particular monument, Appendix 1 ing between mortars from different areas is critical. provides a catalogue with an introduction to each one For example, both O. Lamprecht and R. Malinowski followed by a list of the relevant vaulting techniques provide useful studies of ancient Roman mortar, but with cross-references to discussions in the text. A their samples are not from Rome itself.2 In recent glossary of technical terms used is also provided at years, Italian engineers and geologists, often working the end of the book. with preservationists, have become more active in the analysis of mortar and concrete samples from build- ings in Rome and Ostia, and, in Chapter 3,Ihave the nature of roman concrete incorporated these results in an effort to provide the most relevant information regarding the local mortar. Roman concrete, or opus caementicium, is different from what we think of today as concrete. The word caementa means rough, unhewn quarried stones and concrete vaulting during the republic refers to the rubble of fist-sized pieces of stone or broken brick that were used in the mortar as ag- The development of concrete vaulting during the gregate. As implied by its name, the concrete in an- Republic has been covered admirably by W.