At the origins of Pompeii: the plant landscape of the Sarno River floodplain from the first millennium bc to the ad 79 eruption

The ad 79 eruption of the Vesuvius severely affected the floodplain surrounding the ancient city of Pompeii, i.e. the Sarno River floodplain. The landscape was covered with volcaniclastic materials that destroyed the ecosystem but, at the same time, preserved the traces of former environmental conditions. This study provides—for the first time—a pollen sequence reconstructing the environmental evolution and the plant landscape of the Sarno floodplain between 900 and 750 cal bc and ad 79, i.e. before and during the foundation of the city, and during its life phases. Previous geomorphological studies revealed that the portion of the Sarno floodplain under the “Pompeii hill” was a freshwater backswamp with patchy inundated and dry areas. Palynology depicts a thin forest cover since the Early Iron Age, suggesting an open environment with a mosaic of vegetation types. The local presence of Mediterranean coastal shrubland, hygrophilous riverine forest and mesophilous plain forest is combined with the regional contribution of mountain vegetation through the sequence. Oscillations between inundated and wet ground characterized the studied area until the ad 79 eruption. Such a natural environment shows anthropogenic traits since pre-Roman times: pasturelands, cultivated fields and olive groves, which probably occupied drier soils. The most important change in the land use system was the introduction of cabbage cultivation in the fourth century bc and its intensification from the second century bc, when Roman influence grew. The presence of tree crops and of ornamental trees reveals the opulence of the Imperial age until the catastrophic eruption

Pollen analysis of the Pleistocene lacustrine succession of Vallo di Diano (Campania, Italy)

Five sedimentation facies were recognised: fluvial, fluvio-lacustrine, lacustrine, marshy and alluvial fan. The pollen analysis of the lacustrine succession enabled to point out two 'glacial-interglacial' cycles. The glacial periods are characterised by high amounts of herbaceous taxa. In particular, in the first glacial period a higher percentage of steppic elements, denoting arid climate, has been found. The interglacial periods are characterised by high amounts of arboreal taxa. The higher percentage of high temperature and water demanding taxa in the second interglacial period indicates that the climate was warmer and wetter than in the first one. The pollen diagram cyclicity together with the tephrostratigraphical and chronostratigraphical data enabled to correlate the analysed succession with the isotopic stages 13 to 16

SULL'ORIGINE DEI PONTI AD ARCO IN LEGNO: IL RUOLO DEI COLLEGAMENTI

In this study two timber bridges are analyzed, which constitute examples of structures with arch behaviour obtained assembling straight elements of reduced dimensions: Traian’s bridge on Danube River and the military bridge drawn by Leonard from Vinci. For each one, starting from available surveys in literature, a structural definition based upon an accurate interpretation of the behaviour of connections between the straight elements, needed for arch configuration, has been made. Leonard’s military bridge shows an arch configured by rectilinear rods, disposed on staggered planes, jointed by lashings. The exam of some papers in the Atlantic Code, relating to this bridge and to studies on details of connections made by lashings, has allowed the recognition of the military bridge joints as an application of the mechanism used by roman carpenters in building Caesar’s Bridge on Rhine River, following the interpretation given by Palladio. Joint’s behaviour schematization, introduced in a proper numerical modelling, has allowed verifying the real arch behaviour of the structure drawn by Leonard. For Traian’s Bridge, a new hypothesis on structure design has been proposed, different from those existing in literature, but more appropriate for technological level of its building times; the given interpretation recognizes in this work the first example of a bridge with an underlying polygonal centring. An experimental study on scale models has allowed introducing in the numerical modelling different degrees of stiffness of the joints between straight elements making the arch and double hanging posts. From numerical results the need of spacing transversal joists comes out at the aim of induce an equilibrated distribution of normal stresses between the three polygonal profiles of the arch structure

TIMBER ARCH BRIDGES: A DESIGN BY LEONARDO

In this study structural behavior of the timber bridge drawn by Leonardo by Vinci in Fol.22 r.a Atlantic Code is analyzed, which can be ascribed to a special timber arch bridge typology. In fact, the arch behavior is obtained by the spatial disposition of rectilinear joists. Based upon Leonardo’s sketch, a geometric model of the military bridge has been made, focusing upon the more interesting technological aspects of this solution: timber beams connections, made resorting to special lashings; timber beams disposition on staggered planes, making a crushproof spatial whole, which behaves like an arch. In such reconstruction, the technological abilities of the epoch in which the bridge would have had to be built are kept in mind. At this aim, the study of the Palladian reconstruction of Caesar’s bridge on the Rhine is particularly meaningful, in relation specifically to connections with lashings. With reference to the disposition of timber beams, it is of great interest the comparison with the bridge built in 2000 at Jinze, in the outskirts of Shanghais, as a reproduction of the ancient "rainbow bridge ", built during the Sung Dynasty (960-1280 A.D.) in the city of Khaifeng

THE MARVELLOUS TIMBER TRUSSES OF XVIII CENTURY

Nineteenth-century manuals and treatises when specially devoted to art of carpentry, like the work of Krafft (1805) or of Emy (1841), as well as when investigating the whole building theory and practice like the treatise of Rondelet (1810), paid great attention to timber trusses of large span. In fact, illustration of past and current technical capabilities of carpentry as guides to professional exercise was one of principal aims of those authors. Between the most quoted examples of large span timber trusses there are the covering structures of the “exercise halls” which were built at the end of XVIII century to allow military exercise during winter. These structures, together with some examples of the beginning of XIX century, as that designed by M. Betancourt and built in Moscow in 1818, are the apex of carpentry art before new technologies and new materials provided a different way of covering large spaces. In particular, two roof trusses designed by the German carpenter Schuhknecht show the high achievements of carpentry art, because of the large span, the structural conception and the technical arrangements: - the covering structure of the exercise hall in Darmstad (Germany), built in 1771/72 and demolished in 1892 to allow the construction of the Landesmuseum, with a span of about 44 m; - the covering structure of an exercise hall to be built in Moscow, designed in 1781, but never constructed, with a span of about 84 m. A geometrical scheme of those structures, based upon historical surveys, has been derived to study their structural behaviour; then the structural scheme has been deduced paying great attention to technological solutions designed for internal joints. The aim of this structural analysis has been not only the evaluation of the reliability of their design, but also the understanding of the carpenter structural intuitions on which this design is based. An enlightening factor is the critical review of the interpretation and judgement of these constructions couched by authors of famous and widespread treatises like Rondelet and Emy. Consequently this analysis gives also the opportunity to understand their structural ideas about timber trusses

THE SWISS COVERED TIMBER BRIDGES OF XVIII CENTURY

In history of timber carpentries, great interest comes out of Swiss covered bridges from a technological as well as a structural point of view. Beyond the numerous testimonies of such still existing works, acquaintance of the most important realization is offered by the consultation of handbooks on carpentry, like those of Krafft (1805) and Emy (1841), and by widespread works as Rondelet’s treatise (1810). The bridge object of the present study constitutes a singular case as it is reproduced by some treatise writers as a bridge realized in the city of Wettingen, on Limmat River, but in truth it was never constructed. It is instead only the first design, set aside later on, proposed by Hans Ulrich Grubenmann for Rein River crossing at Schaffahausen. The interest for such design is motivated by the extremely dared structural conception: the potentialities of the structural scheme composite with struts arranged in the vertical surface aside of the track, already adopted in many illustrious examples of the past, come exalted through the connection of such structures with those of the covering central skeleton, realizing an effective spatial scheme. A calculation scheme, based on the reproductions of the original design, and on a precise reconstruction of technological solution adopted at the end of eighteenth century in Switzerland, has been conceived to verify the reliability of this design which, with a free span of about 120 m, represents the attainment of a limit never equalled

Timber Coverings of the Palatine Chapel in Caserta Royal Palace

The analysis of the timber covering structure of Palatine Chapel in the Royal Palace of Caserta, built in the eighteenth century by Luigi Vanvitelli, is the object of the present study. The interpretation of its structural behaviour has been based upon a detailed survey and visual as well as non destructive inspections. Results of decay analysis have shown presence of confined damaged areas, which in any case do not induce exceeding safety limits, or loss of serviceability. At the aim of understanding the designing process followed by the architect in deciding the best disposition of the structural elements and specifically in choosing the slope of the underlining inclined posts more efficient to optimize structural behaviour, a comparative analysis has been done on different theoretical schemes obtained varying that slope. Numerical results evidence how little modification on Vanvitelli’s scheme will not leave the same safety margins