Theories of Urban Design

Theories of Urban Design

• Urban design theory seeks to offer a scientific perspective.
• The three main types of urban design theories relate to the subject, object, and knowledge within urban design

Subject of Urban Design Theories

• Subject theories address what needs to be done to achieve a specific result, such as the image of the city.
• These theories help provide potential to control urban events.
• They explain real-world problems and devise general concepts applicable across different scenarios.
• Subject theories tend to reflect values like safety, democracy, justice, and common sense.
• Compositional mass and space theories consider only two dimensions, but occasionally three, and are closely related to morphological debate.
• Theories about the city image includes the work of e.g. Lynch in 1960.
• Theories, such as Jacobs' (1984), addresses safety.
• Social interaction is addressed by Whyte (1980) and Gehl (2011).
• Identity enhancement theories study the history and meaning of cities, such as Kostof's work in 1999.
• Other theories cover urban health, urban design management, and sustainability.

Object of Urban Design Theories

• Object theories portray urban design as a cohesive field and explain how conscious design activity forms urban spaces.
• "Theories of" urban design are different from "theories in" urban design.
• The object of urban design has two types of theorizing

Descriptive Emphasis

• Descriptive emphasis provides a wide view of what an urban design object is about, for example Lynch (1981), Carmona et al (2003).

Prescriptive Emphasis

• Prescriptive emphasis tries to explain how to improve the object of urban design, for example Bentley (1987).

Theories about Knowledge of Urban Design

• These theories consider the actual knowledge of urban design as a subject of study (e.g., Lang 2005).
• While potentially unhelpful for practice, they provide a sense of understanding the field and are intellectual studies that fall into the subject or object categories.
• Two types of theories exist about knowledge
• Theorizing urban design knowledge from the perspective of other disciplines involves applying fundamental concepts, usually from social sciences.
• Theorizing from within, for example Carmona 2014, involves grounding theories within existing discourse, but being informed by discussions from other fields.

Examples of Theories

• The Image of the City
• The Death and Life of Great American Cities
• Public Places, Urban Spaces: The Dimensions of Urban Design
• Townscape
• Architecture of the City
• Responsive Environment: A Manual for Designers

Principles of Urban Design: Linking Theory to Practice

• Traditional (Original) Neighborhood design includes:
• Super block of residential units grouped around a central green, separation of vehicles and pedestrians, and a road hierarchy with culs-de-sac for local access roads.
• Neighborhood serves as a unit of the city (Patricios 2002).

Elements of "Image of the City" and Structuring Elements

• Townscape analysis has three main aspects: legibility, permeability, and visual analysis.
• Legibility of the urban structure involves ways people perceive, understand, and react to the urban environment and qualities that give a place its identity.
• Permeability of the environment considers the choices an urban setup offers to users.
• Visual analysis examines urban space, facades, pavements, rooflines, street structure, and visual details.
• A legible environment can be structured by people into accurate images
• When the user can react to the environment more effectively it indicates that that a clear perceptual image is present.
• Mapping the common image of the city is fundamental for urban design study.
• Five features structure the city image for users: Paths, Nodes, Landmarks, Districts/Quarters, and Edges.
• Paths are routes for movement by vehicles, cycles, and pedestrians.
• Paths are significant for image building, connecting other imaging features to their networks.
• Pedestrian paths make distinctive districts and quarters, important places, and are established with decorations.
• Nodes are focal points of activity in the city, junctions, market squares, and interchange
• Chris Alexander suggests interesting paths have nodes of activity at a maxium distance of 300m.
• Nodes are classified by type, function, and importance, often with a city center as the most important node.
• Landmarks are reference points experiences at a distance, being 3-dimensional sculptural objects, which may be natural or man-made, like buildings or monuments.
• Landmarks help in providing directions to strangers
• Landmarks may not always be great monuments but can be unique street fixtures.
• Across traditional cities, religious buildings are frequently the tallest structures.
• Districts and quarters are sections of a city with identifying characteristics
• The district or quarter is a medium to large scale section of the city
• Districts within the city are clearly apparent and given names, and those residents contrast themselves with outsiders.
• Each district has a boundary to mark its end and another's begining
• Areas (quarters) with distinctive boundaries, paths, nodes, and landmarks.
• Paths, nodes, landmarks, and district designs provide structuring ideas for urban designers to create memorable spaces.
• Edges, as places with beginnings and ends, have defining boundaries
• Edges are 2-dimensional linear elements
• Examples of edges include railway lines, canals, rivers, and sea fronts.
• "Fleshy" boundaries, according to Chris Alexander, will "permit movement to reflect the complexity of the city life"
• Edges permit movements between districts, changing architectural styles between city districts.
• Permeability relates to public and private accessibility
• A civilized society ensures citizens may walk the streets safely and the public and private realms are a legitimate concern in the urban design
• How public spaces divides the environment into blocks determines physical and visual permeability
• Smaller blocks increase route choice, larger blocks reduce the choice.

Permeability Factors

• Street layouts should have street blocks of one acre to one hectare
• Street junctions should be at the of centers of 70 to 100m, creating a pattern of street blocks
• Street block pattern gives a measure of permeability, flexibility, and accessibility.
• Degree of permeability is defined as the choice level and variety of routes.
• Hierarchical layouts based on the cul-de-sac reduces the choice of routes
• Depending on the intensity of the usage there is public safety on the street: streets see increase safety when heavily used or overlooked by surrounding buildings.
• The frontage (interface) sits between the public and private space.
• Frontage allows a mechanism for ensuring privacy, maintaining a friendly environment on public streets, and graduating between spaces.
• Frontage supplies security with views from front gardens, balconies, bay windows, porches, etc..

Transformation of Urban Space

• Urban catalysts are anything that precipitates a process
• A negative catalyst is called Occas
• An element that promotes the changing of city structure, its speed, and mode of city development has a positive impact
• Urban catalysts have a chain-reactive potential of individual development on civic growth and urban regeneration.
• Urban catalyst theory states the strategic introduction of new elements might revitalize existing ingredients of the urban center without radically changing them.
• Urban catalysts stimulate new life, affecting the form, character, and quality of subsequently introduced urban elements, while functioning incrementally and continuously regenerating the urban fabric.
• Characteristics of urban catalysts include: new tangible elements like hotels, shopping malls, transport hubs, enhanced elements, not damaging context.
• Intangible urban catalysts impact (e.g., policies, historical events, guidelines), where its product or impact is better than its ingredients and is not consumed
• Related urban interventions: Urban Renewal, Urban Regeneration, Urban Revitalization, Gentrification

Energy Efficiency in Buildings

• The building sector leads in world energy consumption, mostly for heating, cooling, lighting, and artificial ventilation
• Sustainable energy saving will help enormously, requiring major change to supply and use.
• Energy is indispensable for socio-economic development and quality life in all nations
• Global energy consumption doubled between 1971 and 2011 and continues to rise
• As a result of unnecessary individual needs, total energy consumption is growing faster than population
• Per capita energy consumption has increased by 11.8% in 10 years with improvements, activities, and geographical dispersion.
• Economic factor of GDP increases relate to the influences on total final consumption directly.
• Electricity consumption has grown even as a third of the global population lacks access
• Undeveloped and developing nations mostly use fossil fuels
• Social economic Development includes increased comfort, and entertainment activities are factors influencing energy consumption in buildings.
• Geography: Daylight/Location and Climate also impact consumption.
• Architectural Design/Technology also plays a key role

Architectural Design/Technology

• Shape and energy optimization influences solar energy and total energy consumption with solar radiation; therefore, compactness is key.
• Compactness with exposed surface to heat losses must be low and the shape factor should address the ratio of building length to depth (SF).
• Orientation is important in passive solar design.
• The Building Envelope is the Foundation, roof, doors, and windows

Building Elements

• Shading on buildings controls solar radiation.
• Passive Systems.
• The conceptual design phase is the best time to integrate energy-efficient strategies.
• Energy efficiency reduces the economic costs during the buildings useful use due to the lowering of energy consumption.

Measures and Policies

• Policies and measures to reduce consumption and promote efficiency includes renewable energy development, but it the largest area, renewable energy, is at 18%
• Three categories of policy exists
• Regulatory measures like building regulations make mandatory and set minimum requirements.
• Soft instruments are voluntary standards, for example the need for certifications for beyond regulation.
• There is the need for Economic incentive for motivation, specifically to improve energy efficiency by undertaking refurbishment.
• There is also the Tax exemptions / reduction and capital subsidies,.
• Building Regulations: building (thermal) regulations provides legal and mandatory requirements, compliance, and to promote energy performance.
• Building labels and Certifications encourages higher sustainability and has new requirement such as LEED, BREEAM, GBCA.
• The target should be Low Energy, Passive, and Zero Energy Buildings.

Barriers to Energy Efficiency Implementations

• Economic Barriers include cost and financial determinants, equipment costs, investment access and inadequate micro-credit institutes for energy services.
• Social Barriers such as behaviors, and lifestyle/culture influence energy use, plus current energy components and environmental consciousness.
• There are also Political/Institutional Barriers such as short term concerns, non vigorous planning, and a lack of subsidies and synergy.
• Furthermore Other Barriers exist such as climate conditions, appropriate production technologies, and data and information errors.

Suggestions to Remove Barriers

• Co-implication of all actors to implement energy efficiency policies., for all Institutions and Individuals
• Research for financial support for Local and international partnerships, and for complementarity between private and state to bridge technology gaps.
• Use market- based regulatory instruments to reduce costs and share new technologies.
• Other suggestions include a need for local energy audit programs and more media involvement.