Notes on the city walls of Chester, historical and constructive /

"Reprinted from The Journal of the British Archaeological Association."

Prison in city walls, Manila, PI

Insurrectos in the cells of the big wall receiving visits from friends.

Diversity of vascular plants growing on walls of a Brazilian city

City walls are very specialized environments, conditioned by human activities. There is little information about plants that invade human-made habitats, and no study done in Brazil with plants growing up on walls. The aim of the present study was to survey the wall vascular flora of a Brazilian city, comparing the diversity found in its downtown and neighborhoods. Fieldwork was done in Jundiaí, São Paulo State, where data was collected in downtown and in five neighborhoods. In each place, three transects of 1 km were established and every plant individual was registered. Twenty-eight species were identified, all of them on the downtown transect and most also on the neighborhood transects. Five species were the most frequent, although none were dominant. The diversity indicies of the six transects were not significantly different, with an overall diversity of H′ = 2.93. © Springer Science + Business Media, Inc. 2006.

Lod Commemorative Coin

Obverse: Front view of a plane, airport buildings, in the background relief of old buildings in the city. Reverse: City coin of Lod, minted at the beginn9ng of the third century CE by Emperor Caracalla, on the coin a head of Tyche (Fortune) looking to the left, she wears a crown representing city-walls and towers.

La Ricostruzione 3D di Bologna nel XVI Secolo

Il lavoro presentato ha come oggetto la ricostruzione tridimensionale della città di Bologna nella sua fase rinascimentale. Tale lavoro vuole fornire un modello 3D delle architetture e degli spazi urbani utilizzabile sia per scopi di ricerca nell’ambito della storia delle città sia per un uso didattico-divulgativo nel settore del turismo culturale. La base del lavoro è una fonte iconografica di grande importanza: l’affresco raffigurante Bologna risalente al 1575 e situato in Vaticano; questa è una veduta a volo d’uccello di grandi dimensioni dell’intero tessuto urbano bolognese all’interno della terza cerchia di mura. In esso sono rappresentate in maniera particolareggiata le architetture civili e ecclesiastiche, gli spazi ortivi e cortilivi interni agli isolati e alcune importanti strutture urbane presenti in città alla fine del Cinquecento, come l’area portuale e i canali interni alla città, oggi non più visibili. La ricostruzione tridimensionale è stata realizzata tramite Blender, software per la modellazione 3D opensource, attraverso le fasi di modellazione, texturing e creazione materiali (mediante campionamento delle principali cromie presenti nell’affresco), illuminazione e animazione. Una parte della modellazione è stata poi testata all’interno di un GIS per verificare l’utilizzo delle geometrie 3D come elementi collegabili ad altre fonti storiche relative allo sviluppo urbano e quindi sfruttabili per la ricerca storica. Grande attenzione infine è stata data all’uso dei modelli virtuali a scopo didattico-divulgativo e per il turismo culturale. La modellazione è stata utilizzata all’interno di un motore grafico 3D per costruire un ambiente virtuale interattivo nel quale un utente anche non esperto possa muoversi per esplorare gli spazi urbani della Bologna del Cinquecento. In ultimo è stato impostato lo sviluppo di un’applicazione per sistemi mobile (Iphone e Ipad) al fine di fornire uno strumento per la conoscenza della città storica in mobilità, attraverso la comparazione dello stato attuale con quello ricostruito virtualmente.

La costruzione della città medievale. Archeologia dell'edilizia storica e topografia urbana a Pistoia.

Pistoia rientra a buon diritto, nel quadro della Toscana medievale, in quella rete di centri urbani di antica origine e tradizione diocesana che riuscirono a costruire, nella dialettica fra città e territorio, un organismo politico autonomo, il comune cittadino. La ricerca prende in considerazione i resti materiali delle strutture conservate nel tessuto urbano attuale, in particolare l'edilizia civile, prediligendo la cosiddetta “edilizia minore”, ovvero gli edifici residenziali non monumentali che, proprio per questo motivo, sono generalmente poco conosciuti. Le strutture, censite ed inserite in una piattaforma GIS (Arpenteur), sono analizzate con metodo archeologico al fine di distinguere le diverse fasi costruttive, medievali e post-medievali, con cui sono giunte fino ad oggi. L'analisi stratigrafica, effettuata su rilievi realizzati mediante modellazione 3D (Photomodeler), ha permesso di costruire un primo “atlante” delle tipologie murarie medievali della città: i tipi murari assumono quindi la funzione di indicatori cronologici degli edifici analizzati. I dati stratigrafici, uniti al dato topologico dei complessi architettonici (localizzati prevalentemente nel centro storico, all'interno del circuito murario della metà del XII secolo), hanno fornito informazioni sia per quanto riguarda l'aspetto materiale degli edifici di abitazione (forma, dimensioni, materiali) sia per quanto riguarda temi di topografia storica (viabilità maggiore e minore, formazione dei borghi, orizzonte sociale degli abitanti, distribuzione della proprietà), nel periodo della “parabola” della Pistoia comunale (XII-XIII secolo). In conclusione, la ricerca vuole essere sia uno strumento di analisi per la storia delle trasformazioni delle città nel periodo comunale, sia uno strumento di conoscenza e tutela di un patrimonio storico-archeologico che, per la sua natura non-monumentale spesso sfugge all'attenzione di amministratori ed urbanisti.

Città e architettura a Faenza nel Rinascimento. Progetti e strategie di rinnovamento urbano nell'età di Carlo II Manfredi (1468-77)

La tesi ha come oggetto il rinnovamento urbano che fu realizzato a Faenza per opera del suo signore Carlo II Manfredi tra il 1468 e il 1477, d’accordo con il fratello, il vescovo Federico. La prima opera realizzata da Carlo fu il portico a due livelli che dotò di una nuova facciata il suo palazzo di residenza, di origini medievali. Questa architettura sarebbe stata il preludio di un riordino generale della piazza principale della città, probabilmente allo scopo di ricreare un foro all’antica, come prescritto dai trattati di Vitruvio e di Alberti. L’aspetto originale del loggiato rinascimentale, desumibile da documentazione archivistica e iconografica, permette di attribuirlo con una certa probabilità a Giuliano da Maiano. Oltre alla piazza, Carlo riformò profondamente il tessuto urbano, demolendo molti portici lignei di origine medievale, rettificando le principali strade, completando la cerchia muraria. Federico Manfredi nel 1474 diede inizio alla fabbrica della Cattedrale, ricostruita dalle fondamenta su progetto dello stesso Giuliano da Maiano. L’architettura della chiesa ha uno stile largamente debitore all’architettura sacra di Brunelleschi, ma con significative differenze (come la navata definita da un’alternanza tra pilastri e colonne, o la copertura composta da volte a vela). L’abside della cattedrale, estranea al progetto maianesco, fu realizzata nel 1491-92 e mostra alcuni dettagli riconducibili alla coeva architettura di Bramante. A Faenza si realizza in un periodo di tempo brevissimo una profonda trasformazione del volto della città: loggiato, riforma della piazza, riordino delle strade, una nuova cattedrale, tutto contribuisce a dare lustro ai Manfredi e a fare di Faenza una città moderna e in cui si mettono in pratica, forse per la prima volta nell’Italia settentrionale, i dettami di Vitruvio e di Alberti.

Dutch boundaries

In many schools of architecture the 1970s have been an important watershed for the way in which architecture was taught. For example, recent studies have stressed the importance of Aldo Rossi for the changes in the teaching of architec-ture at the ETH in Zürich that before was based on orthodox modern principles. A similar struggle between an orthodox conception of modernity and its criticism took place at the architectural faculty of Delft, in the Netherlands. Although Delft is an important European school of architecture, the theoretical work produced during this period is not largely known outside the Netherlands. This is perhaps due to the fact that most studies were published in Dutch. With this article, I intend to make the architectural theory developed during this period known to a larger public. The article describes the intellectual journey made by Dutch stu-dents of architecture in the 1970s and 1980s. This was the quest to receive recognition for the intellectual substance of architecture: the insight architecture could be a discourse and a form of knowledge and not only a method of building. Specifically, the work of the architectural theoretician Wim Nijenhuis is highlight-ed. However, as I point out in this article, the results of this journey also had its problematic sides. This becomes clear from the following sentence taken from the dissertation of Wim Nijenhuis: "The search for metaphysical fiction and the tendency towards a technological informed absolute through fully transparent and simultaneous information, should be contested by a fantasy dimension, that does not wish to 'overcome' a given situation and that does not rely on 'creativi-ty' (that would still be historical and humanistic)." Texts like this have a hermet-ic quality that is not easy to comprehend for an architectural public. Even more, there is an important debate looming behind these sentences. As an important outcome of their quest the architectural students in Delft asked themselves: how do we give form to architectural theory once its claim to truth is exposed as an illusion? For Nijenhuis, the discourse about architecture is a mere 'artful game with words': a fiction, besides other forms of fiction like poetry or literature. The question is then if we have not entered the realm of total subjectivity and relativ-ism with this position. From what can the discourse of architecture derive its authority after the death of God?

Neue Überlegungen zur Datierung der westlichen Befestigungsanlagen Aššurs

This paper focuses on the construction date of the Neo-Assyrian city walls on the western front of Ashur. W. Andrae and his team excavated the walls on a large scale and established that they were both referred to in Shalmaneser III’s inscriptions. However, a reconsideration of the archaeological and textual evidence suggests that not the „Binnenwall,“ but the „Niederwall“ was constructed at the same time as the „Außenwall.“ This implies that Shalmaneser III’s inscriptions actually never mentioned the „Binnenwall“ which was probably not built until the end or even sometime after of his reign.

Taking a New Look at Neo-Assyrian Gates

The Assyrian capitals are not only known for their magnificent temples and palaces, but also for their monumental city walls. The most impressive and at the same time most delicate features of all the town defenses were the city gates. As they interrupted the line of defense, they were al-ways a vulnerable spot of every system of fortifications. However, the walled cities’ economic needs demanded these gateways to be built, in order to ensure the steady flow of goods and pro-visions. Apart from that, they also had a significant ideological meaning, which is emphasized by many cuneiform texts. During the excavations of the Assyrian capitals of Ashur, Dūr Šarrūkīn, and Nineveh, a fairly large number of Assyrian city gates were brought to light. By re-examining the archaeological reports and employing remote sensing, many details of these structures can still be revealed. The paper aims at illuminating the different considerations that went into constructing these gates, as well as the development Assyrian city gates underwent and what may have influenced this process.

Neo-Assyrian concepts of fortification

The major cities of the Neo-Assyrian Empire were not only home to impressive palaces and temples, but they were also equipped with strong fortifications. The city walls were not only meant to keep out potential enemies, but by demonstrating Assyria’s power to any approaching person, they served an ideological purpose, as well. However, military efficiency was just as crucial, since, over its entire history, the empire repeatedly faced internal and external threats and could not have afforded to lose any of its urban centers which were essential to maintaining control over the various provinces or geographic regions associated with them. The study of Neo-Assyrian fortifications relies on evidence provided by archaeological excavations, the study of Assyrian reliefs and information from cuneiform texts. Even though these sources help us reconstruct the appearance of the town defenses, the question of why the individual fortification systems were built in a specific way cannot be addressed by these means alone. Remote sensing offers an opportunity to view the course and placement of the city walls within their topographical context. Furthermore, geographical information systems (GIS) offer a tool to illustrate the distribution of the strongly fortified Assyrian towns, thereby allowing us to recognize patterns and functions of regional fortification systems during the Neo-Assyrian period.

Wedges and plate-bandes: mechanical theories after De la Hire

Plate-bandes are straight masonry arches (they are called, also, flat arches or lintel arches). Ideally they have the surfaces of extrados and intrados plane and horizontal. The stones or bricks have radial joints converging usually in one centre. The voussoirs have the form of wedges and in French they are called "claveaux". A plate-bande is, in fact, a lintel made of several stones and the proportions of lintels and plate-bandes are similar. Proportions of plate-bandes, that is the relationship between the thickness t and the span s (t/s)varies, typically between 1/4–1/3 in thick plate-bandes, and is less than 1/20 in the most slender ones. A ratio of circa 1/8 was usual in the 18th Century and follows a simple geometrical rule: the centre form with the intrados an equilateral triangle and the plate-bande should contain an arc of circle. The joints are usually plane, but in some cases present a «rebated» or «stepped» form. Plate-bandes exert an inclined thrust as any masonry arch. This thrust is usually very high and it requires either massive buttresses, or to be built in the middle of thick walls. Master builders and architects have tried since antiquity to calculate the abutment necessary for any arch. A modern architect or engineer will measure the arch thrust in units of force, kN or tons. Traditionally, the thrust has been measured as the size of the buttresses to resist it safely. Old structural rules, then, addressed the design problem establishing a relationship between the span and the depth of the buttress. These were empirical rules, particular for every type of arch or structure in every epoch. Thus, the typical gothic buttress is 1/4 of the vault span, but a Renaissance or baroque barrel vault will need more than 1/3 of the span. A plate-bande would require more than one half of the span; this is precisely the rule cited by the French engineer Gautier, who tried unsuccessfully to justify it by static reasons. They were used, typically, to form the lintels of windows or doors (1-2 m, typically); in Antiquity they were used, also, though rarely, at the gates of city walls or in niches (ca. 2 m, reaching 5.2 m). Plate-bandes may show particular problems: it is not unusual that some sliding of the voussoirs can be observed, particularly in thick plate-bandes. The stepped joints on Fig. 1, left, were used to avoid this problem. There are other «hidden» methods, like iron cramps or the use of stone wedges, etc. In seismic zones these devices were usual. Another problem relates to the deformation; a slight yielding of the abutments, or even the compression of the mortar joints, may lead to some cracking and the descent of the central keystone. Even a tiny descent will convert the original straight line of the intrados in a broken line with a visible «kink» or angle in the middle. Of course, both problems should be avoided. Finally, the wedge form of the voussoirs lead to acute angles in the stones and this can produce partial fractures; this occurs usually at the inferior border of the springers at the abutments. It follows, that to build a successful plate-bande is not an easy matter. Also, the structural study of plate-bandes is far from simple, and mechanics and geometry are related in a particular way. In the present paper we will concentrate on the structural aspects and their constructive consequences, with a historical approach. We will outline the development of structural analysis of plate-bandes from ca. 1700 until today. This brief history has a more than purely academic interest. Different approaches and theories pointed to particular problem, and though the solution given may have been incorrect, the question posed was often pertinent. The paper ends with the application of modern Limit Analysis of Masonry Structures, developed mainly by professor Heyman in the last fifty years. The work aims, also, to give some clues for the actual architect and engineer involved in the analysis or restoration of masonry buildings.