Intensity and Diffusion

INTENSITY AND DIFFUSION THE IDEA THAT THE TRADITIONAL CITY OF INTENSITY CAN BE TRANSPOSED TO THE EDGE IN ORDER TO INTENSIFY A DIFFUSED AREA

ASYA IVANOVA

First Published 2015 by the Print Unit at the University of Dundee, Perth Road, Dundee, Scotland, DD1 4HT Designed and typeset in Adobe Aparajita Printed and bound in Great Britain First Edition Š 2015 All rights reserved.

INTENSITY AND DIFFUSION

Asya Ivanova University of Dundee Master of Architecture Thesis

CONTENTS Abstract 9 Introduction

11

I. Urban intensity AA files The Surface Density Cognitive architecture

17

II. Cities of different intensities Porto Stop City Exodus Archipelago

23

III. Principles Open up/ assemble/ integrate/ invite to intensify Close in/ disperse/ segregate/ repel to diffuse Vehicle traffic Prospect-refuge theory and the choice of space Scale and distance Edge zones and walking

31

IV. Urban forms to transpose intensity Factors of intensity Accessibility Entrances Ground floors Setbacks Buildings’ age

37

Critical Reflection 43 of the traditional city and the modern expansion

Acknowledgements 49 Bibliography 50

ABSTRACT

The modern city expands outwards, not inwards. It forms itself around a centric core of high urban intensity, surrounded by diffused areas of residential sprawl. There is no defined end to the city. Every expansion becomes a new image of the city, a build manifesto of the present and aspiration for the future. Porto’s urban expansion follows Avenida da Boavista – an urban axis of 7 km to connect the city interior with the Atlantic. With the accommodation of vehicle traffic into the urban environment a certain quality of intimacy of streets has become unmanageable and consequently lost. This raises a concern that with the expansion of cities the urban intensity becomes lost.

This thesis explores the perception of urban intensity, determines a number of spatial configurations facilitating it, and re-applies it in zones of sub-urban diffusion. It examines the voids and forms of the city that become “red hot spots”1 of activities, their dispersal over the surface, and potential to be transferred. Rob Krier discusses in Urban Space that “our modern cities have lost sight of the traditional understanding of urban space”.2 This thesis applies methods of intensification used in the traditional city in order to urbanise the modern extension.

By understanding what makes space intense an emphasis is put on capturing the physical and non-physical qualities of urban spaces.

_______________ 1

Gabriele Mastrigli, Modernity and Myth: Rem Koolhaas in New York (San Rocco Magazine issue 8, 2013). pp 10-27

2

Rob Krier, Urban Space (London: Academy Editions, 1979). p 15

8 |9

INTRODUCTION

10 |11

Beginning of Av. Boavista, Porto, in black superimposed on the end

…we are thinking of architecture’s capacity to charge the space around it with an energy which can join up with other energies, influence the nature of things that might come, anticipate happenings... a capacity we can feel and act on, but cannot necessarily describe or record.3 Smithson and Smithson, The Charged Void

The depiction of what Alison and Peter Smithson call the ‘charged void’ refers to the qualities of urban spaces and how architecture predisposes a concentration of activities to take place promoted by the proximity of people and mix of uses. Defining, measuring, and re-applying this ‘charge’ has been attempted by both architects and planners ever since the Modern movement.

The theme of this paper is Intensity and Diffusion as a conceptual frame for understanding the spatial connections between the urban and suburban environment of a city. Dictionary definitions of intensity include great concentration, amount or degree of strength, great energy, etc. ChineseBelgian architect Li Mei Tsien describes it in her paper Breathing Spaces: Intensity rather than density Urban intensity does not have a specific definition. It could be defined as the expression of density in terms of quality … density alone can never qualify the city. Urban intensity goes beyond the mere quantitative notion of urban density by maintaining or expanding urban nodes of respiration, and by creating mixed and multifunctional spaces.4

The dictionary defines diffusion as “The spreading of something more widely; Dissemination of elements, with synonyms such as scattering and dispersal”. Both antonyms intensity and diffusion could be applied to describe qualities of the built environment on various scales: city, district, street, room. Most medieval cities can be described as intense because of the concentration of buildings while today a higher percentage of cities’ surface is diffused due to the suburban sprawl.

_______________ 3

Alison Smithson and Peter Smithson, The Charged Void: Urbanism (New York: Monacelli Press, 2005). p 11

4

Li Mei Tsien, Breathing Spaces: Intensity rather than density < http://www.wbarchitectures.be/en/posts/_Breathing_Spaces___intensity_rather_ than_density_/153/> [19 Jan 2015]

12 |13

Av. Boavista, end to end overlay

Boavista, end to end overlay 1:2500

Old towns remain a magnificent instrument in comprehending the influence built form has on the daily life of people. They are effective at reflecting the needs and activities that would take place in fairly small settlements where pedestrian traffic is the basis behind the urban planning. Our cities grow to change and every expansion becomes a built manifesto of the zeitgeist – classical, modern, postmodern, etc. With the accommodation of vehicle traffic into the urban environment a certain quality of intimacy of streets has become unmanageable and consequently lost; replaced by wider distances, monolithic facades, and open green spaces.

Old towns designed to solely accommodate pedestrians are not an obsolete romantic notion of the past, but favourable places for their fundamental qualities of scale, beauty, and intensity. Can architecture evolve to translate those properties in areas of urban diffusion such as coastal edges and city peripheries? Decoding urban intensity and ways of its application in city edge zones is to be explored through the insertion of a water sports learning facility at the threshold between two diffused environments: Porto’s city park and the Atlantic Ocean, at the very end of Porto’s expansion datum – Avenida da Boavista.

Social structure here often consists of the family/household as the smallest unit. Between this unit and the very large unit – the city centre or shopping centre – only diffuse subdivision exists.5 Jan Gehl, Life between buildings

In contradiction to Gehl’s social structure of the traditional city it is possible to assume an intense subdivision between diffused entities, one with defined physical structure to engage and be experienced at close range. Transferring qualities of intensity and diffusion into a building project involves an understanding of the physical planning for isolation and contact, analysing the use of public space, and defining the typical conditions, forms and structures of such spaces.

Similarly spatial characteristics of urban enclosures can dictate the co-relationships between public and private rooms of the design program.

_______________ 5

Jan Gehl, Life Between Buildings: Using Public Space (New York: Van Nostrand Reinhold, 1987). p 58

14 |15

The aim of the thesis is to adopt methods of intensification characteristic for the traditional city and apply them in diffused edge zones. The first section analyses existing research in the area in order to demonstrate the areas chosen to develop. The third section explains a set of planning tools used to generate favourable conditions in public spaces and examines how the prospect-refuge theory could be beneficial to the research by clarifying how people use space and consequently how to intensify it.

In order to perceive the qualities of intensity and diffusion and successfully transfer them to a new piece of architecture a comparison between four cities, both real and conceptual proposals, and five urban forms or enclosures along Boavista is carried out. The cities highlighted in section II are Porto, Stop City by Pier Vittorio Aureli, Exodus London by Rem Koolhaas et al, and Green Archipelago by Oswald Mathias Ungers et al. The enclosures discussed in section IV were selected in relation to urban form and ways of transposing urban intensity. Aim of the study is attempt to create an appraisal of built form associated with intensity of public activity. Both enclosures and cities are judged by their organisation into intense and diffused zones, legibility, permeability, and visual complexity. In this case Porto is representative of the traditional European city and a location for the thesis project, while the other visionary projects critique the existing city by proposing insights to its future.

I. URBAN INTENSITY

16 |17

The Surface (1969) pg 19

The idea of urban space as a typology was topic researched by many architects and historians, more expansive by Elia Zenghelis and Rem Koolhaas when teaching the Diploma Unit 9 between 197374. It was an exploration of the “type of life” in a city as a “desired domain and artificial territory for the maximum fulfilment of the aspirations of non-alienated, social man”.6 In the AA Prospectus the program is focused on to urban forms to facilitate the expansion of the city by creating areas of urban intensity: “Points ( . ) and Lines (¬) of urban radiation and attraction.”7 Projects on the basis of the creation of an Ideal City would suggest applying “new injections of urban intensity in the areas of urban growth”.8 The idea of understanding the city through its intensity was explored by Rem Koolhaas in unpublished manifesto named The Surface in 1969 while studying at the AA. In the form of a storyboard he introduced the city as a “plane of tarmac with some red hot spots of urban intensity”. 9 In this manifesto it becomes clear that the surface is the city and the spots of urban intensity constitute the sources of “city-sense” and contribute to the identity of the city. He aims to disregard the function of architecture as problem-solving “urban medicine” but make his objective the “interpretation and design of the city as a whole”.10 The modern city expands outwards, not inwards. It forms itself around a centric core of high intensity, surrounded by diffused areas of residential sprawl. There is no defined end to the city.

Identity of the city is lost in its suburbs. The city becomes private farther out of its central zone, where street edges with generic garden walls and lack of public interaction gives away a sense of community in isolation and alienation. …By working on nodes, or points of urban intensity, we can create, wherever necessary, places that act as beacons, light buoys on an urban scale, in landscapes without landmarks. Finally, to achieve all this, the whole area needs remodelling, i.e. the connections and the links between the various parts of the patchwork have to be redesigned.11

Alfieri & Minetto discuss in the periodical Zodiac the creation of public space. The relation between street and city is based on consistency and continuity opposed to informal scatter. Not only have they raised awareness to the necessity of new points of urban intensity but also they assert the need for stronger connections between the points.

_______________ 6

Roberto Gargiani, Rem Koolhaas/ OMA The Contruction of Merveilles (Italy: EPFL Press, 2008). pp 46-56

7

Ibid., p. 46

8

Elia Zenghelis, Unit 9 in Prospectus. Architectural Association. School of Architecture. (London: AA Publications, 1973-74). pp18-20

9

Gabriele Mastrigli, Modernity and Myth: Rem Koolhaas in New York (San Rocco Magazine issue 8, 2013). pp 10-27

10

Ibid.

11

Bruno Alfieri and Renato Minetto, Zodiac. An International Review of Architecture (New York: Rizzoli, issue 13,1995). p 105

18 |19

1

2

3

4

Initial diagrams exploring density on an urban scale 1. Current condition at the coastal end of Boavista 2. Montage of Portoâ&#x20AC;&#x2122;s Old town onto the suburban park 3. Montage of Matosinosâ&#x20AC;&#x2122; grid onto the suburban park 4. Montage of Corbusian blocks (Ilot insalubre No 6) and residential suburbs

DENSITY It is assumed that a denser environment can channel more activity as chances for pedestrian interaction is higher. Higher densities increase the number of necessary and optional activities, reduce transportation and lead to increase in the land value. As Tsien noted density alone does not constitute the charge of a place.12 While density remains a measurable entity of people occupying a defined area, intensity depends on the quality of the surface. The mere number of possible interactions is irrelevant and out of the designer’s control.

The surface of the city is the place urban intensity resides. This surface includes the city’s streets, squares, and ground floors. The spaces of the city we anticipate to share with others. In contrast there are areas such as urban parks, coastal promenades, gardens, and where we experience seclusion. Analogue on this occupational basis can be drawn between the rooms of a house: the living room being a space for variety of activities between many occupants, and the bedroom – a space of being on your own.

If capturing intensity equals an intention to capture human activity, ideas in cognitive architecture could be used for exploring the streets of a city as a generator of intensity. Urban intensity levels are higher in streets than those in open public squares. Sussman and Hollander sum up in Cognitive Architecture: Designing for How We Respond to the Built Environment an understanding people’s experience of spaces they move through.

People are bipedal, they have two feet and they walk with eyes facing forward. People rarely look backwards or up. They almost never walk sideways or backwards. They dislike taking stairs.13

Although this statement of given human behaviour does not predict the liveliness or a choice of space people prefer to occupy, it speaks of the general way of experiencing the urban environment through the field of vision and speed of walking (through streets’ edges).

_______________ 12

Li Mei Tsien, Breathing Spaces: Intensity rather than density < http://www.wbarchitectures.be/en/posts/_Breathing_Spaces___intensity_rather_

13

Ann Sussman and Justin Hollander, Cognitive Architecture: Designing for How We Respond to the Built Environment (New York: Routledge,

than_density_/153/. Last accessed 19 Jan 2015.> [19 Jan 2015] 2015). pp 10-55

20 |21

II. CITIES OF DIFFERENT INTENSITIES

22 |23

Centric urban intensity in Porto, figure ground plan

PORTO The city of Porto is selected as the scene for intervention with focus on Avenida da Boavista urban axis, an east-west datum to guide the expansion of the city towards the ocean. As the avenue was constructed in four main phases between 1784 and 1917, it is representative of the difference in the urban environment throughout its 6.8 km length as if dissecting the city, from the centre to outskirts.

It makes its beginning at the military square of Santo Ovidio and meets the ocean by the fortress of S. Francisco Xavier. As part of the ‘1784 Improvement Plan’, a central government initiative, Boavista’s main intention is to be an “extension with links to specific local entities (the municipality and the main economic organisations related to the exploitation and trade of the port wine)”.14 Throughout its length a change of urban to suburban environment is apparent, as well as the way the width of Boavista changes to accommodate two vehicle lanes at its beginning and six at its termination roundabout. The length of the strip predisposes vehicle traffic opposed to pedestrian, and while in the first quarter of the avenue 4 to 5-storey high buildings from the edge of the sidewalk, soon after the Rotunda da Boavista more and more buildings are set back from the sidewalk thus creating a fractured enclosure.

Porto’s urban intensity forms a centric pattern from the old town outwards. The growth of the city engulfs surrounding areas of intensity but does not sustain intense walking routes between them.

The aim of the project is to use the intensity of urban form to bridge areas of sub-urban diffusion at the very end of Boavista where the city park meets the beach. The water sports centre is to become a beacon on an urban scale to intensify the experience of arrival and transition to the ocean.

_______________ 14

Rui Tavares and Clara Vale, Porto 20th century urban centralities. Two study cases: Aliados administrative central plan (Barry Parker) and

Boavista urban axis. Urban development between town planning and real-estate investment. < http://www.fau.usp.br/iphs/abstractsAndPapersFiles/ Sessions/23/TAVARES_VALE.pdf> [25th Mar 2015]

24 |25

Edge urban intensity in Stop City, aerial view

Walled urban intensity in Exodus, plan

STOP CITY In Dogma P. V. Aureli proposed the conception of a city limit in order to create “constraints and processes of stoppage to the endless growth of the city”.15 He adopts a view of formal architecture to represent the city limit – eight dense slabs measuring 500x500 meters, 25 meters thick, forming an edge zone of high intensity around a diffused 3x3 km square of forested landscape. Each slab acts as a self-sufficient vertical city. This city model is a critique of utopian projects like No-Stop city by Archizoom and Vertical City by Hilberseimer, which allow for repetitive grid-based city expansion. Aureli adopts the form of a border to the “limitless urbanization” where the border contains and becomes the city itself.16 In this example the urban intensity instead of spreading across the surface of the City is translated vertically becoming an edge that overpowers the context.

EXODUS In 1972 Rem Koolhaas, Madelon Vreisendorp, Elia Zenghelis, and Zoe Zenghelis proposed a strip of enclosures formed by two parallel walls across London. Once separated from the urban fabric, the strip becomes a prison of metropolitan scale for the voluntary segregated individuals. The Strip accommodates eight squares, each devoted to a single activity. The marvels of these confinements turn the strip into a zone of “intense metropolitan desirability”.17 The urban intensity of the city is contained within the walled rooms of Exodus, where segregation from the fabric creates a desire of occupation. The strip is an exploration of the “intense and devastating” power of the wall, usually a tool of separation, but in this case used with good intentions.18

_______________ 15

Pier Vittorio Aureli and Martino Tattara , Dogma: 11 Projects (London: AA publications, 2013) pp 7-29

16

Ibid.

17

Roberto Gargiani, Rem Koolhaas/ OMA The Contruction of Merveilles (Italy: EPFL Press, 2008). pp 46-56

18

Rem Koolhaas, Elia Zenghelis and illustrators Zoe Zhenghelis and Madelon Vriesendorp, Exodus or the voluntary prisoners of architecture < http://socks-studio.com/2011/03/19/exodus-or-the-voluntary-prisoners-of-architecture/> [20th Mar 2015]

26 |27

Fragmented urban intensity in Archipelago City, plan of West Berlin

Image of Corbettâ&#x20AC;&#x2122;s proposal to solve congestion21

ARCHIPELAGO In The City in the City – Berlin: A Green Archipelago Ungers, Koolhaas et al propose a process of identifying and intensifying urban fragments of post-war Berlin. The project does not aim to fix the broken nature of the city but instead, aims to intensify the pieces as urban islands within a green network of landscapes.

Ungers regards it as “intensification of the complexity of the city as a complementary organisation” an ideology in contradiction to urban repair.19 While urban repair promotes the fixing of any broken fabric of the city (in Berlin’s example would take rebuilding of the post-war debris) this theory creates a group of intense island-like city fragments which act as cities within the city. The connective surface between them is simply diffuse park land. Intensification proposed on the urban islands of the archipelago involves imposing new structures or unbuilt projects within the existing fragments. The city project is aimed to “intensify rather than diminish the sense of a Metropolis”.20 In Delirious New York Rem Koolhaas discusses a similar proposal to solve the problem of the congested metropolis by Harvey W. Corbett based on a system adopted in Venice. The proposal discusses separation of vehicle and pedestrian traffic over two different levels. Arcades carved into the buildings would allow for more lanes of traffic to occupy the ground plane while pedestrian bridges across ‘the flood of rapidly rolling vehicles’ would act as connections to the pedestrian islands.21 This mode of “very modernised Venice” would embrace congestion as its culture and replicate the city within the city model of Berlin, where each block of the Manhattan grid becomes an island.22

_______________ 19

Oswald Mathias Ungers, Rem Koolhaas, Peter Riemann, Hans Kollhoff, and Arthur Ovaska, The City in the City – Berlin: A Green Archipelago (Zürich: Lars Müller Publishers, 2013). pp11-55

20

Ibid.

21

Rem Koolhaas, Delirious New York (Italy: Monacelli Press, 1994). pp120-127

22

Ibid.

28 |29

III. PRINCIPLES

30 |31

1

2

3

Diagrams exploring street planning23 1. To open up & to close in 2. To assemble & to disperse 3. To integrate & to segregate 4. To invite & to repel

4

This section looks at the general principles adopted in urban design and planning that influence the levels of intensity in urban spaces. It explores the city on a street level where individual buildings influence the experience of moving through space in a collective manner. In addition the prospectrefuge theory is discussed to bear an understanding of peopleâ&#x20AC;&#x2122;s behaviour and use of public space.

Equally important in attempting intensification is the integration of vehicle traffic, scale of urban squares, and distance between buildings in the edge zones.

Open up/ assemble/ integrate/ invite to intensify Main objectives within the city are smoother transitions between public and private areas, and careful design of the border zones between them. The success of a public space relies predominantly on the careful dimensioning of the opening, its situation in relation to pedestrian stream, sight lines, and edges. According to Gehl when designing to invoke contact no walls or barriers should be intended, distances should be kept short, speed of the traffic kept low, with public space occupying the ground floor level and main building orientation towards the clearing.23 Close in/ disperse/ segregate/ repel to diffuse Gehl observed that segregation leads to a diffused suburban pattern situated mostly in outskirt areas of the city.24 The pattern of widely spaced private homes with setback from the sidewalk 3-7m off the main street (front garden) act as a private distance barrier to the pedestrian.The front garden might be diffused correspondence to the public areas within buildings on central urban streets occupied by shops, cafes, bars, etc which constitute active edges. Hard edge facades of monolithic character are usually blank against the edge of the sidewalk to decrease the visual field of pedestrians by repelling to diffuse.

Vehicle traffic Important factor in the perception of urban streets accommodating both pedestrian and vehicle traffic is the width of the road, speed of the traffic, number of car lanes, and possibility for crossing. Fast vehicle traffic allows for a division of the two parallel ends of the street and makes communication across difficult. In such examples the road becomes a divider of the public space rather than a collector of the activities, isolating pedestrians to the edges.

_______________ 23

Jan Gehl, Life Between Buildings: Using Public Space (New York: Van Nostrand Reinhold, 1987). pp 80-127

24

Ibid.

32 |33

Piazza Ascoli Piceno, Italy: people tend to gather around the edges of the square27

Prospect-refuge theory and the choice of space In terms of formal organisation a suggested pattern of 4m wide streets of solely pedestrian traffic increases the intensity of the transitory space, which potentially encourages events and conversations to occur. The human field of vision predisposes horizontal movement on a flat surface (ground floor plane) with a viewpoint of 1.70m above it. To describe the rule of the edge we need a deeper understanding of the prospect-refuge theory according to which groups of people assemble on the edge of an open external urban space.25 The position provides extensive views over the spatial opening as well as the proximity of a refuge. The body position is facing the clearing with its back closest to the boundary wall. Inversely in internal public space’s most favourable position is nearest to the openings with the prospect of the outside. Additionally the prospect-refuge theory covers similar ground to theories of agoraphobia in conventional psychoanalytic theory. In this case individuals experience anxiety in environments of vast openness or crowdedness.

Scale and distance The perceptual structure of small urban spaces tends to be experienced with higher intensity. In traditional towns narrow streets of terraced housing form the majority of the town while buildings of greater importance (public, religious, etc.) are taller and bigger in size, situated at street nodes or at the end of plazas. A sense of legibility moving through the town is increased by main public squares or parade streets being lavishly decorated with ornaments, monuments, fountains, etc.

The small enclosure of narrow streets tends to be perceived as warm and personal by pedestrians.

In modern developments the legibility of urban structure has been highly impaired by the use of large impersonal spaces, wide streets, fast traffic, and taller buildings. The perception of larger architectural dimensions often provokes feelings of psychological alienation. Gehl describes it as the distance between buildings corresponds to the distance between people: “Buildings, as well as, people are kept at a distance.”26

_______________ 25

Ned Crankshaw, Prospect-refuge theory. In Creating Vibrant Public Spaces: Streetscape Design in Commercial and Historic districts.

(USA: Island Press, 2009). pp12-20

26

Jan Gehl, Life Between Buildings: Using Public Space (New York: Van Nostrand Reinhold, 1987). p 68

27

Ibid., p. 148

34 |35

Edge zones and walking If the edge fails, then the space never becomes lively . . . the space becomes a place to walk through, not a place to stop. 28

C. Alexander, A Pattern Language

The affiliation of pedestrians with the edge zones is explained by the prospect-refuge theory which defines the pedestrian norm, as people prefer to walk along the edges of an open plaza rather than diagonally crossing it. Activities occur at the edges and spread towards the centre. Preferred walking distances of 5-10 minutes can benefit from alternating streetscape with modest squares, which has the advantage of making distances seem shorter by being subdivided into stages, providing sense of transition and arrival. The walking distance is often subjective as far as the quality of the route is considered. A sequence of urban rooms can improve the quality of a route and decrease the perception of its length. In this case sight lines are important to the success of adjacent spaces as activities in the space could act as invitation.

Drawing further comparisons between the beginning and end of Boavista, in the beginning the buildings open up towards the pedestrian extending the public space within, as opposed to the end where closed private gardens with blank boundary walls lack any public interaction. Intense experiences take place on foot, where both activities and people are assembled, â&#x20AC;&#x153;it is possible for individual events â&#x20AC;Ś to stimulate one anotherâ&#x20AC;?.29 In order to achieve more equal intensification of city activities over the districts, quiet spaces could be designed to complement more lively ones.

Traditional cities benefit from the integration-oriented city structure while functionalistic cities segregate the use of buildings into mono-functional areas.

_______________ 28

Christopher Alexander, Murray Silverstein, and Sara Ishikawa, A Pattern Language: Towns, Buildings, Construction (USA: Oxford University Press, 1977). p 600

29

Jan Gehl, Life Between Buildings: Using Public Space (New York: Van Nostrand Reinhold, 1987). p 81

IV. URBAN FORMS TO TRANSPOSE INTENSITY

36 |37

2

1

Diagrams exploring Av. Boavista 1. Corner café on a cross junction in the first quarter of Boavista 2. Edge buildings’ entrances in the first quarter of Boavista 3. Souto the Moura Tower, middle section of Boavista

3

FACTORS OF INTENSTY This section takes a closer look at Boavista’s surface in terms of measuring the dependency of activity on urban form and its change along the length of the avenue. It attempts to apply the general principles of active and intense urban spaces to Boavista while determining reasons for a decrease of activities along its length. Activities involve economic establishments of public and private interest which operate from the surface of the street. Factors in the success of those establishments are the network of routes (accessibility), the number of entrances along the edges, the heights of the ground floor in relation to the surface; the setbacks from the sidewalk; and the age diversity of edge buildings.

The popularity of place relies on its accessibility within the infrastructural network of the city.

Establishments on corner sites generate more activity as they can be approached from four or more destinations. For example a corner café on Boavista’s intersection with Augusto Luso St occupies a negative corner (with external seating) used as a tool of congregation. The accessibility to and from an activity establishments include all the routes that could be used to arrive at the location.

Whether the establishment is approached on foot or by car, can result in a choice of different route due to vehicle traffic routes and parking availability, but essentially good position in the streets’ network always results in better accessibility and higher intensity.

When discussing the street network a gross number of entrances could dictate the activity of street spaces. Building entrances are perceived to be both destinations and origin of pedestrian activity.

Streets with more entrances generally channel more pedestrians. In the case of Boavista the number of entrances in the beginning is higher compared to the middle and end sections of the avenue, which further contributes to the decrease of urban intensity.

The height of the ground floors adjacent to the street edge, whether submerged or elevated add a degree of privacy, but reduce accessibility from the street. Heights above one meter reduce significantly sightlines between outside and inside. The implication of elevated ground floors is more often applied in the middle section of Boavista where residential buildings elevate the ground floor due to desire for increased privacy and security. It is applied as well on few commercial buildings, more prominent the Souto de Moura tower where a plinth elevates a public platform level off the street.

38 |39

Fractured edge of residential blocks in the second section of the avenue

Diagrammatic street of mixed age buildings

Setbacks reduce the level of intensity because they prolong the journey by additional distance and effort from the nearest pedestrian route and building entrance. Wider setbacks decrease the visibility and approachability of a place. While in the first part of Boavista very few buildings have a setback, soon after Rotunda da Boavista residential properties apply wider setbacks to increase the privacy and effort to access, and reduce visibility and noise from the avenue.

Of equal importance is the buildingsâ&#x20AC;&#x2122; age which is directly connected to the time and construction methods of its period, and thus contribute to the intensity of the street.

Buildings from different eras display a body of knowledge of their time which can stimulate associations and meanings that intensify the cognitive experience of a street.30

Sevtsuk et al, Capturing Urban Intensity

In Boavstaâ&#x20AC;&#x2122;s example the buildings age range from 1700s for buildings in the very beginning of the strip (including the Xavier fort & college building at the coastal end) to present day. The avenue was built in four main phases and its urbanisation follows the periods of expansion as the buildings at its beginning are older than the ones at its termination.

When analysing Boavista many aspects contribute to the decline of urban intensity along its length: the expansion of vehicle traffic lanes; faster speed of traffic; fragmentation of the avenueâ&#x20AC;&#x2122;s edges due to wider setbacks; decreased number of entrances; elevation of the ground surface; segregation of solely residential function; and the lack of public attraction (intentional implication of public venues along the way).

_______________ 30

Andres Sevtsuk, Onur Ekmekci, Fare Nixon, and Reza Amindarbari, Capturing Urban Intensity. 2013 <http://idc.sutd.edu.sg/wp-content/ uploads/2014/07/2013-Capturing-Urban-Intensity.pdf.> [17th Feb 2015]

40 |41

CRITICAL REFLECTION of the traditional city and the modern expansion

42 |43

The city spreads its surface between and within its buildings. This complex relationship forms different patterns of spatial configurations; urban forms that determine the quality of places. The life between buildings is dependent on “the nature and distribution of human activities”. Sevtsuk et al state their concern that with the expansion of cities the urban intensity might become lost and “physical transformations could result in as significant social transformations”.31 Boavista, an axis making its start in the traditional urban centre of Porto and reflecting the urban redevelopment of the city’s expansion, is a perfect example for an empirical study of its intensity and lack of. The research links the relation of urban form to quality of the created environment in order to determine the success of urban space. As Rob Krier discusses in Urban Space “our modern cities have lost sight of the traditional understanding of urban space”.32 The research adopts methods of traditional urban spaces and applies them to intensify the modern expansion.

Boavista was anticipated when planned to act as a guideline of Porto’s expansion to the Atlantic Ocean, but along its length it becomes a mundane highway to the shore. It loses its urbanity and despite injections of investment does not meet the intensity of the urban centre. Unfortunately the urban fabric of Boavista is not only indicative of Porto’s expansion but it is a true reflection of present urban developments.

_______________ 31

Andres Sevtsuk, Onur Ekmekci, Fare Nixon, and Reza Amindarbari, Capturing Urban Intensity. 2013 <http://idc.sutd.edu.sg/wp-content/ uploads/2014/07/2013-Capturing-Urban-Intensity.pdf.> [17th Feb 2015]

32

Rob Krier, Urban Space (London: Academy Editions, 1979). p 15

BOAVISTA END TO END OP

INTENSITY / DIFFUSION

PPOSITIONS

N

Streets can accommodate multiple functions. They constitute the lines of urban intensity. The capacity of extruding public space within the ground floors of street edge buildings is a traditional tool in supporting local commerce and generating activities. Often the connective linkage between outdoors and indoors influences the character of a street.

The term urban intensity is closely related to the spaces between buildings, or the phenomenon Alison and Peter Smithson term as ‘the charged void’. The fact that traditional towns remain as beacons of public activities can be due to the proximity of people and services. What is meant by intensifying a diffused area does not always translate as densification. It implies the creation of new origins of urban intensity by bringing activities to the edges or peripheries of cities.

Urban intensity is a condition that occurs at the streets’ edges, where the subject occupies the spaces between or inside buildings, consequently the city edges should be designed to become the new ‘red hot spots’ of activities. Once we define a perception of central urban intensity within Porto and explore ways to be distilled, we can look into its direct application in city edge zones of diffusion.

If the city is to have a defined urban end: an edge beyond which instead of suburban sprawl only farmlands, fields, and forests exist, an intensification would build up against this city wall very much similar to town walls in the past. In such a hypothetical scenario intensification of the city can occur from the edge inwards where structures of public activity would be planted in areas of diffused character. Lines of urban intensity would form along the shortest routes, making distances walkable and possibilities of interaction greater. The problem of defining an edge to the city would not take away from the potential surface of the ever growing Metropolis, but rather transpose the intensity of the centre, relieve it from its unnecessary congestion, and supplement areas of new city identity.

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My thesis project endeavours the creation of spaces of public attraction to support a mixed-use urban environment. By promoting high concentration of pedestrian traffic, mix of land use, and adoption of one extended surface level to bridge land and water the intensity of the site is to increase.

My project was selected to test the hypothesis of bridging diffused areas of Portoâ&#x20AC;&#x2122;s natural edge where Boavista meets the Atlantic Ocean. It is an area adjoining the city park to the coast. Boavistaâ&#x20AC;&#x2122;s termination roundabout separates the traffic north-south along the coast. The link to the north is via an elevated motorway which connects to the neighbouring town of Matosinos. Few buildings of public interest in the area are a 17th century fort, a shopping centre, and a seasonal cafĂŠ. The project proposes a water sports centre to draw activities to the edge and facilitate an intense subdivision between the park and the water.

The park folds down and a series of lakes and paths lead onto a paved platform of planted trees.

The sense of movement through the park creates a continuum of trees canopies, which lead under the motorway, through the boat yard, under the building, along the pool, follows the marina until the end of the breakwater.

Urban intensity can happen at the edges, not only at the centres of cities or territories. This seemingly extraordinary statement, however counterintuitive, is leading us to the concept of the empty centre, the diffused middle, and the intense edge. My project attempts to intensify Porto not by intensifying its old centre, but by intensifying its new edge. The water sports centre becomes a new node where several forms of traffic intertwine: pedestrian, boat, car, street, and elevated highway. As emphasized in the beginning intensity does not equal density, and consequently the building project itself takes one per cent of the surface of the intervened area.

Part of the project of intensification is to raise awareness and experience of edges. The edge is always a shared border between two territories which excludes the assumption of an edge and nothing beyond it. In this sense the project is an edge between two territories: an ocean and suburban park.

The visionary city projects discussed in section II explore the problem of intensification and achieve it by two entirely different planning strategies: at the edges of cities [Aureli] and in the island-like centres of cities [Ungers]. These two strategies correspond to the difference between contemporary and traditional cities. Traditional cities intensify their centres, contemporary cities intensify their edges.

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ACKNOWLEDGEMENTS

I would like to express my special thanks of gratitude to my tutors Dr Lorens Holm and Dr Cameron McEwan, whose guidance throughout this process has been invaluable.

I must further note my appreciation to Amy Sleight and John Melling, whom I was lucky to share this final year with on Costa da Boavista.

Finally, I would like to recognise the rest of the Rooms + Cities group members for numerous advice in times of doubt.

Asya Ivanova Dundee, April 2015

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