Mediaeval church vaulting,

Thesis (Ph.D.)--Princeton university, 1915.

Similarities and Differences in Barrel Vaults of Traditional and Stately Houses in the Historic Centre of Arequipa, Perú

The traditional architecture of the centre of the city of Arequipa has been analyzed by comparing floor-plans of houses from the eighteenth and nineteenth centuries in order to explain the reasons behind the arrangement of their constructional elements and the evolution of said elements and floor-plans. The historic centre of Arequipa, a city located in the South of Perú, South America (Latitude 16°23' South, Longitude 71 °31' West), is based on a ground plan from 1540 that was set during the city's Spanish foundation. It was declared Patrimony of the Humanity by UNESCO. The manorial architecture is widely known for its decorated fronts and one-of-a-kind designs, but its differences with respect to the popular architecture are not based exclusively on decorative aspects. Peru's colonial period finished around 1825, but the barrel-vault, construction style continued in Arequipa through 1868, when an earthquake destroyed the city. Thereafter, the vaults were replaced by roofs made of rails, with cinders made out of the lava stone. The stately houses belonged to the founding families who settled around the main square on forty nine blocks that formed a square-grid, street layout. Also belonging to this category are the houses of landlords and traders from post-colonial times.

Technical Challenges in the Construction of Gothic Vaults: The Gothic Theory of Structural Design

The construction of a Gothic vault implied the solution of several technical challenges. The literature on Gothic vault construction is quite large and its growth continues steadily. The main challenge of any structure is that, during and after construction, it must be "safe", that is, it must not collapse. Indeed, it must be amply safe, able to support different loads for long periods of time. Masonry architecture has shown its structural safety for centuries or millennia. The Pantheon of Rome stands today after almost 2,000 years without having needed any structural reinforcement (of course, the survival of any building implies continuous maintenance) . Hagia Sophia in Istanbul, finished in the 6th century AD, has withstood not only the dead loads but also many severe earthquakes . Finally, the Gothic cathedrals, with their appearance of weakness, are• more than a half millennium old. The question arises of what the source of this amazing strength is and how the illiterate master masons were able to design such daring and safe structures . This question is usually evaded in manuals of Gothic architecture. This is quite surprising, the structure being a fundamental part of Gothic buildings. The present article aims to give such an explanation, which has been studied in detail elsewhere. In the first part, the Gothic design methods "V ill be discussed. In the second part, the validity of these methods wi11 be verified within the frame of the modern theory of masonry structures . References have been reduced to a minimum to make the text simpler and more direct.

Technological development in Spanish gothic vaults design

The principle of complexity as the evolution vector of the gothic style was an idea largely developed by Paul Frankl. The high complexity reached in the 15th and 16th centuries was possible thanks to the geometrical resources developed in the workshops of the medieval stonemasons. The search for more sophisticated designs was possible also with the higher standardization, so that the most complex ribbed vault could be built with ribs that had all the same curvature and with voussoirs that were therefore identical. Spanish Gothic architecture has been deeply studied from a historical and artistic point of view. The present paper, as a complement to these analyses, aims to point out some of the geometrical methods and technological improvements that late medieval masons were able to develop. In that way, some selected vaults have been measured, in order to study their geometry and design process. Also scale models of some vaults have been built at the Escuela de Arquitectura (Madrid) to validate these geometrical principles. More than just a research method, the scale models allow to understand the medieval construction techniques, and they are a powerful pedagogical tool with which pupils can reach a rewarding experience based on the “medieval-way” praxis.

Crossed-arch vaults in late-gothic and early Renaissance vaulting: a problem in building technology transfer

Crossed-arch vaults are a particular type of ribbed vaults. Their main feature is that the ribs that form the vault are intertwined, forming polygons or stars and leaving an empty space in the middle. The firsts appear in Córdoba in the second half of the 10th Century. Afterwards, the type diffused through Spain and North Africa, 11th_13th Centuries. These vaults reappear in Armenia in the 13th Century. In the 14th and 15th Century a few examples are found both in England (Durham, Raby) and Central Europe (Prague, Landshut, Vienna). At about the same time, Leonardo da Vinci produced designs for the Tiburio (Ciborium) of Milan cathedral with a cross-arched structure and proposed tests to assess the strength; he also, made use of the same pattern of vault for Renaissance centralized churches. Eventually, the type can be tracked through the 17th (Guarini) and 18th (Vittone) Centuries, until Spanish post war architecture in the 1940-60s (Moya). Some questions arose, which so far, have not been answered. How was it possible that a particular type of vault had such enormous geographical spread? How was it transmitted from Córdoba to the Caucasus? The matter is one of transfer of knowledge, ideas, and technology; it relates both aesthetics and construction.

The construction of sexpartite vaults in Europe

Sexpartite vaults constitute one of the most interesting chapters in European Gothic architecture. Originally, the use of the square cross-ribbed vault was limited to relatively small spaces, but when the need arose to cover spaces of considerable size, a new vault with very peculiar characteristics appeared. This new vault was a cross-ribbed vault that was reinforced in the centre by a rib that was parallel to the transverse ribs which effectively divided the vault in half. This configuration breaks the side arch into two fragments, creating a pair of windows on each side. The volumetrics of these vaults is extremely complex and the difficulties involved in their construction perhaps explain why they were abandoned in favour of the simple cross ribbed vault, now with rectangular sections. The existence of the sexpartite vault barely lasted more than fifty years, from the end of the XII century and the beginning of the XIII. Towards the end of the 19th century Viollet-le-Duc gave a succinct explanation of this type of vault. A. Choisy also, later, devotes some pages to the French sexpartite vault; since then, the subject has only been broached in a few references in later studies on Gothic architecture. However, despite its short period of existence, the sexpartite vault spread throughout Europe and was used to build important vaulting. Viollet-le-Duc's sexpartite vault could be considered to be the prototype of them all, while it is true that the studies that we have conducted so far lead us to affirm that there is a wide variety of vaults, with different volumetric spaces and different construction strategies. Therefore, we believe that this chapter of international Gothic deserves further study applying the knowledge and resources that are available today. This paper has been written to explore the most significant European sexpartite vaults. New measurement technology has led to a revolution in research into the history of construction, allowing studies to be conducted that were hitherto impossible. Thorough data collection using total station and photogrammetry has enabled us to identify the stereotomy of the voussoirs, tas-de-charges and keystones, as well as the bonding of the surfaces of the severies. A comparison of the construction techniques employed in the different vaults studied reveals common construction features and aspects that are specific to each country. Thus we are able to establish the relationship between sexpartite vaults in different European countries and their influence on each other.

Communication Architecture Design for Real-Time Networked Control Systems

Networked control over data networks has received increasing attention in recent years. Among many problems in networked control systems (NCSs) is the need to reduce control latency and jitter and to deal with packet dropouts. This paper introduces our recent progress on a queuing communication architecture for real-time NCS applications, and simple strategies for dealing with packet dropouts. Case studies for a middle-scale process or multiple small-scale processes are presented for TCP/IP based real-time NCSs. Variations of network architecture design are modelled, simulated, and analysed for evaluation of control latency and jitter performance. It is shown that a simple bandwidth upgrade or adding hierarchy does not necessarily bring benefits for performance improvement of control latency and jitter. A co-design of network and control is necessary to maximise the real-time control performance of NCSs