THEORY OF URBAN DESIGN

I. Concept of space

Traditional definitions

 Oxford English Dictionary: Two meanings of space: 1.

2.

Time or duration Area or extension (more common definition) In physics, space has three dimensions (x-y-z axes) and is considered as a volume not an area.

Sir Isaac Newton (17 versa) th C) elaborated that space is absolute….proper to itself…..and independent of the objects it contains (objects fit into space an d not vice-

New Approaches

 1.

2.

Two main categories of space exist: Mental Space (experiential) Physical Space (existential) The notion of space is said to originate in an observers mind and is later imposed as a structure on the physical world….mental space is an image of physical space The concept of space differs from culture to culture…Different cultures have characteristic spatial designs as expressed in their cities, buildings, and art(ref. Dogon villages; japanese Mandala e.t.c) ……but space itself is universal!

(transcends culture)

II. THE CONCEPT OF AESTHETICS



Aesthetics in urban design refers to the creative arrangement of the elements of a town in a beautiful and functional manner.



Order and beauty in a town are a necessity, not an after thought…..they are as much a prerequisite to human health as is fresh air.

Site-City-Observer Relationships

(viewing city from surrounding and vice-versa)

       

Extracted form:

harmony between buildings and nature….

consider basic slopes, angle of hills, vegetation/tree canopies, and rock outcrops. Reflects dominant and pervasive features of nature e.g

Vistas and site supremacy:

view of landscape from the city…beautifully framed countryside (panorama)

Expression:

space markers /symbolgy/ ornamentation/detail e.g towers and minarets; landmarks; accent of urban landscape and skyline

Entrance/Approach:

profound impact of cities on the visitor who traverses long, crowded streets/water.

Colour and light:

choice of colour to reflect aesthetic sensibility; quality of natural light an important visual factor.

Water:

proximity to water and possible interplay a natural asset; water edges, harbours, shorelines, islands, canals e.t.c

Geometry:

form and relationships of angles, lines, curves e.t.c

Human scale:

how each inhabitant would use space and how they would feel in it.

Aspects of Urban Form

(see BUR 203 notes)



Imageability:

Physical Image v/s Functional Image 

Form-Function Relationship



Main Variations of urban form and structure:

Linear, radial, grid, cluster e.t.c



Objectives of urban form

(includes growth; Meaning and identity e.t.c) 

Growth and decline

Existing Theories and Practice

 Theories that have motivated and still inform the construction of cities are both

normative

and

functional.



Normative theories

"goodness“….what is good city form?... and discuss in detail the aspects that create good cities…..

Prescriptive

attempt to specify …..

What cities ought to be!



Functional theories

perform by concentrating on city form processes, spatial and social structure, and form models…… attempt to explain how cities

Descriptive

……

What cities are!

Normative Theories

(selected examples)

1. The Cosmic Model

 It assertions that the form of a permanent settlement should be a magical model of the universe and its gods.

 Such a crystalline city has all of its parts fused into a perfectly ordered whole and change is allowed to happen only in a rhythmically controlled manner  specific phenomena included: such as returning, natural items, celestial measurement, fixing location, centeredness, boundary definition, earth images, land geometry, directionality, place consciousness, and numerology

2. The Machine Model

 The analogy between city and machine has a long history (ref. Egyptian and classical “per strigas”, Ron Heron’s insect city; archigram movement; plug-in concept)  it occurs often when there is no long-term goal in mind but the settlement has to be created hurriedly and its future growth will be determined by still unforeseen forces  Its form requires a few simple rules of urbanization and the outcome is factual, functional and devoid of the mystery of the universe.

 Among its attributes are convenience, speed, flexibility, legibility, equality, and speculation .



3. The Organic Model

The analogy between city and living organism is fairly recent arising with the growth of biology in the 18th and 19th centuries (ref. metabolists)  Model is critical of others, especially the machine model with its "simple grids" as “static”  It asserts that an organism: - is an autonomous being, with a definite boundary and is of a specific size. -does not change merely by adding parts but through reorganization as it reaches limits or thresholds.

- contains differentiated parts but form and function are always linked.

- is homeostatic, self-repairing and regulating toward a dynamic balance.

- undergoes cycles of life and death as is rhythmic passage from one state to another.



Organic model (cont’d)

From this flows the notion of the form of the organic city: - A separate spatial and social unit made up internally of highly connected places and people .

- A healthy community nature of heterogeneous and diverse - The micro unit is the neighborhood , a small residential area, defined by Clarence Perry in 1929 as the support area for an elementary school, to which children, the most vulnerable of the human species, can safely walk.

- Like organisms, settlements are born, grow and mature , and if further growth is necessary, a new entity has to be formed. Thus there are states of optimum size, beyond which pathological conditions ensue.

-

Organic model (cont’d)

Greeenbelts not only ensure an intimate contact with nature but enclose healthy growth.

-A model with typical physical forms patterns, anti-geometrical layouts, and a proclivity for natural materials. , among which radial - Often the systems.

organic idea is extended regionally to connect settlements to valleys, trails and other extended natural -There is an attraction to or services processes. Often the model aligns itself with a socio economic philosophy that sees increases in urban value as the result of endeavor. small-scale modes of production as opposed to large-scale synthetic communal rather than individual



4. The Contextual Model

This relates new development to an analysis of existing urban structure.  A prominent concept of this canon is that of “serial vision” …. the sequential and unfolding nature of urban experience (foreground/middle ground/background), ………………with its corners, divisions/modules, protrusions, and recesses/setbacks e.t.c creating aspects of interest and surprise.  Context is something that has no clear or common spatial definition; thus the impact of contextualism will vary with geographical location and cultural influence.  The mainstream urban design has been strongly influenced by contextualism in terms of a new respect for the overall form of the traditional urban street and block and a concern for public realm  (ref: Imageability (Alcock et al) (Kevin Lynch); permeability (Jane Jacobs); (Standford Anderson). These ideas were later published as adaptability/robustness Responsive Environments

5. The pragmatic Model

 This is whereby urban design is defined according to the needs of the epoch….. where the tools and concepts are used selectively and exclusively in regard to the locality.

 The danger with this model lies in: -Likely loss of understanding of the larger processes affecting urban form - Possible inability of making informed decisions at urban scales - Failure to embrace environmental disciplines that are currently excluded and isolated from mainstream urban design.

6. The Constructivist model

 This explores techniques of form to create urban interventions that express the spatial and temporal complexity of a given age.  “Deconstructionists” techniques of form to express the essential fragmentation in city environments.

are constructivists who use unconventional  Ref. Peter Eisenman in nature, which tends to reject any hint of historical contextualism.

Rem Koolhaas applies an approach that is more mathematical and rational makes free use of the typologies of modernism, recombining them in new and ironic ways Bernard Tschumi Frank Ghery and , exploits the random collisions that results from the layering of unrelated activity frameworks.

Zaha Hadid use unconventional techniques of form to express order among chaos of modern cities



7. Functionalist Model

This was dedicated to exploring new interwoven urban structures that would allow opportunities for social

exchange

influence.

encounter/contact

and whose end result is a humanising   The interpretation of this philosophy, however, varied widely in practice: low-, medium-, and high- density; vehicular and pedestrian segregation e.t.c

( Ref: Aldo van Eyck, Ralph erskine, Giancarlo De Carlo)

8. Rationalist Model

 This offered a morphological/structural approach to urban design that related new urban development to the historical structure of the city and typologies of urban space.  The figure-ground drawing was widely used as a design tool.  As “critical reconstruction”, this method was used to maintain and restore the traditional 19th century street pattern and form of the urban block, street and square, without constraining the contemporary architectural expression of new building additions.

 This was not a plea for unthinking preservation or for regarding the city as a museum; rather, the aim was to explore the deep structure inherent in building types and how built forms accommodate changing, living uses over time.

 (ref. Krier) Robert Venturi, Aldo Rossi, Scott Brown, Colin Rowe, Rob & Leon

Functional DescriptiveTheories

 These are founded on the following characteristics: Urban history: the city is regarded as a unique historic process... explaining cities as derivative of their own culture (ref Sjoberg, Rapoport).

 Urban Ecology: city is regarded as an ecology of people, each social group occupying space according to economic position and class. (Ref. Burgess [concentric model], Weber, Simmel and Spengler)  City economy: regards the city as an economic engine in which space, unlike in the previous category, is both a resource and an additional cost imposed on the economy for production or consumption….location of cities an optimization of raw materials, labour and market locations (ref. Isard,Von Thunen,Christaller)

Functional Descriptive Theories (cont’d)

  Urban Communication: regards the city as a field of forces, a communications network of particles which attract and repel each other much as they do in physics. Sub-sets of these ideas include population potential maps, gravity models, communications flows, and various topological models.  Urban Politics/Governance: understanding the city as a system of linked decisions...affluence, imminent domain, citizen participation in a democratic city; the game theory, in which people interact together according to fixed rules and produce agreed-upon outcomes  Urban Chaos: rejects previous theories of competition and posits the city as an arena of conflict, in which the city's form is the residue and sign of struggle, and also something which is shaped and used to wage it. (Castells, Harvey. Lefebvre, Gordon)

Design Principles and Techniques

 Together these help in the correlation and synthesis of spaces, functions, circulation, sites, and orientation…  Their choice and application (singly or combined) will depend on the problem context

(modus operandi)

 Overall they facilitate the conceptualizing process…..entailing decisions and choices

i)

1. Design Principles

Scale: refers to any system of measurement appropriate to the context. Proportion as an aspect of measurement introduces the aspect of relativity…between two objects…the measured and a universally known object…e.g headroom describes space relative to human height.

A module is one part of a system of relative proportions, where one part can combine with other parts to form a larger object (ref. Le corbusier’s Modulor)

Applications of Scale in urban design

 

Scale and Human vision:

our eyse have two fields of view – general and detailed. General cone of vision 30 deg up; 45 deg down; 65 deg to either side.

The above determines urban scale in several ways: we cannot see an object that is further from us than 3500 times its size…8 feet is normal conversation distance; a person between 3 and 10 ft is in close relationship to us…use of normal voices; we can pick facial details up to about 75ft. Beyond this, there is need to complement with gestures…up to about 450ft…also maximum for distinguishing man from woman…maximum viewing distance for human figures is around 4000ft.

Scale and circulation:

across the country.

scale is determined by the means we employ for movement around the city as well as the way we move between cities Scale is determined by the different modes of movement based on their speeds and sizes, but also characteristics in movement…express versus stop-over/interactive…

Scale and neighbourhood size:

scale of the entire town. The citizen numbers and levels of services will determine the scale of a neighbourhood…the scale of a network of neighbourhoods would determine the



Scale in neighbouring buildings and spaces:

Buildings and spaces have to be in scale with people, as well as in scale with each other….this will also apply to other variables like materials, colour, bulk, and siting.

Intentional variations in scale could be used to achieve emphasis and hierarchy in design of buildings and spaces 

Scale and parameters:

them This is where we use attributes of familiar and known objects and details such as cars, trees, humans, light poles e.t.c to judge the sizes of other things near



Scale versus Age, time, convenience and habit:

Our sense of urban scale varies with our ages and habits….the world of a child begins with the home…as one grows the world enlarges and separate parts are linked together…the scale of their world enlarges Our sense of urban scale is also determined by what we are accustomed to…people adapt to environments with time…say getting used to the skyscrapers around us.

Urban scale may also vary with the temporal cycles of the city…the rush hour with its fast traffic has a different view of scale to the sluggish period of the day, when people have all the time to observe and pick details about the city.

ii) Urban Space:

may be isolated or linked; may be purposely designed to display linkage or to emphasize buildings and objects they contain.

Space may be linear/corridors; squares; or reserves…based on their sizes they define the hierarchy of spatial types…..from small intimate sizes to urban squares and the natural space within which the city is set.

Spaces may also be enclosed or open….45 deg is full enclosure; 30deg is optimal; 18 deg is minimum…anything less is lack of it!

iii) Urban Mass;

This refers to the arrangement of ground surface, buildings, and objects to influence the quality of urban space and to shape urban activity patterns on both large and small scales.

In terms of massing, buildings may be projecting into space, be on a space, or in a space.

Our vision and light conditions govern the way we perceive masses… Vision: 18deg is for object plus context Light: 45deg is for details; 30deg is for whole objects; under bright, clear sunlight the individual parts of objects will tend to stand out…..as light subdues we tend to see less of details and more of the overall object. Sculptured objects are best viewed under even light such as shadow light…thus northern and southern facades may transmit details differently…..depending our position in relation to solar patterns.

iv) Responsiveness;

environmental these could be sensual or  

Sensual:

attempt to cater for all the senses: Visual,Tactile, Auditory, Olfactory, Kinaesthetic

Environmental;

that which provides users with essentially democratic settings and enrich their opportunities by maximising the degree of choice available to them; the available techniques include:

i) Permeability

This refers to the number of alternative routes through an environment; it affects where people can go and where they cannot. This offers choice through accessibility and must be considered at early stages of design.

ii) Variety

This refers to the range of uses availed to people in a given environment; it is the experience of a degree of choice provided by intermix of uses

iii) Legibility

This refers to the ease with which people can understand the layout of a given environment and the kind of opportunities it offers.

iv) Robustness

This refers to the degree to which an environment can be used for different purposes as opposed to those with a single fixed use.

v) Visual appropriateness

This refers to the detailed appearance of a place that makes people aware of the possible uses; it affects the interpretations people put on places.

vi) Richness

This refers to the degree of choice in sensory experiences that a place offers to its users.

vii) Personalisation

This refers to the extent to which people can put their own stamp on a place; decisions about forms and materials of the scheme must be carefully made to support personalization but also protect public role.

Other techniques



Open space technique:

where to build versus where to keep open; a variety of uses…parks, watersheds, public transit lines, airports, e.t.c

An open space structure would be the framework for relating land development to transportation and also allow for other decisions related to community life: schools, churches, playfields e.t.c.



Transportation system technique;

patterns of movement as primary land shapers; morphology of networks against that of the land parcels they define….density of development versus intensity of circulation. Varios levels of network, their hierarchic connectivity, as well as terminal facilities.



Plug-in Technique;

where a modular system such as that of a grid is created and within these defined uses and objects can be “inserted” and removed with ease (flexibility)…initially used as a technique for design of functions in individual buildings but later replicated in city-wide design

Theory Versus Practice

(Why urban design matters)

   We design spaces to attract people (public realm) Urban design creates a framework for our lives.

understanding how humans perceive the physical scale and form of cities is essential to mastering design.

  We feel and experience urban design every day Every road width and building height delivers a message to their users on how to use the public realm

 Design brings order and relation into human surroundings  Different designs affect residents in different ways, and make the city’s image more vivid and memorable  Embedded in urban design theories is the fundamental goal of balancing private development and public good in a way that incorporates the social, economic, and cultural needs of a diverse urban population  Urban design must solve practical problems of functionality first and foremost, as it creates tools for people and their quality of life.