Urbanism

Natural Development

Natural development relies on codes to determine the correct arrangement of buildings. Urbanism has too many time-sensitive inputs to immediately generate designs. A city cannot be master-planned all at once because we can't know who will make up the city and how they will want to live. We can't survey enough of the land in enough detail to simulate what would develop naturally. Codes generate an environment in which to design buildings. We use spatial codes and zoning codes to create future possibilities. When done correctly, urbanism gives architects the inputs for architecture rules.

The Public Commons

Public space includes public circulation in between buildings, such as streets, squares, plazas, and parks, as well as buildings that serve as public amenities, like a coffee shop.

Each level of community is made up of multiple "private" spaces that belong to the level below it, plus the shared "commons", which includes circulation space. The different scales of community are nested within each other: Town > Neighborhood > Street > Property > Building > Room > Activity Space

Levels of Community

A town is made up of its town center (TC) and several neighborhoods. The town center is the public commons, which itself is a neighborhood. It supports the other neighborhoods. The primary circulation is through its main street, which is connected to the town center.

Neighborhoods have a central hub, with an elementary school, corner store, bus stop, garden, café, etc. Services can be located at the edge of the neighborhood, which is more accessible from main street, as long as it's within walking distance of the residents. The neighborhood is accessed through side streets.

Streets include the properties on either side of them. The common space is the right of way shared between the properties. The building façades create a sense of enclosure for the right of way, as do street trees. Long streets can be divided into two streets according to where it feels like it changes.

Properties are divided into buildings and yard. The yard is the common space of the property. It has walkways and driveways that lead to the buildings. Two properties with separate parking might share a driveway in common.

Buildings break down into circulation and rooms. Outdoor spaces at the building scale includes the front yard and back yard. They are at the same scale as buildings. At the room scale, outdoor spaces include outdoor rooms, such as a play area or seating area in the backyard. Each outdoor room has its own outdoor activity spaces, such as a shed or a flower bed.

Spatial Organization

Shared space makes up the commons. The commons doesn’t have to be in the center, but it must be accessible from the private spaces. It makes sense to have a central commons, but depending on the circumstances, the shared space could be associated with a specific building, or located across the street, as long as it’s accessible.

Formal Codes

Enclosure and a sense of space

We create public space by using buildings to enclose a commons. The common space may form a street, an alley, a park, etc. 

Buffer space around buildings

The sides of the building should not be encroached by other buildings. Buffer space ensures that each building has natural light and views. In a dense environment, the side buffers can be sacrificed for more buildings, placed right next to it, or attached at the sides like a rowhouse.

The size of blocks

Buildings only need to be accessed from one side, so blocks can be two lots deep without requiring streets everywhere. Lots with access from both sides can have two buildings because the alley provides access to the garage building.

Blocks that are too large should be divided into smaller blocks to increase density and walkability. Blocks that are larger than two lots deep can split to allow access to additional lots deeper within the block.

Buildings form a cluster with the buildings across the street, as well as within their block, especially if the backyard is an open commons.

Street Patterns

Cities are a network of nodes. A node is a point of interest that is connected to other nodes. Early settlements began as outposts at important sites, like bodies of water, which then expanded outwards.

First-Generation streets connect distant places. At the node, the street becomes a main street.

Second-Generation streets are radial streets that extend out from the center. They become busy streets like avenues.

Third-Generation streets are grid-like streets that connect existing streets. They are through streets, or a beltway that goes around the edge.

Street Connections

• Cul-de-sacs can be third-generation dead end streets that cut into a block. They can be second-generation side streets that don't have a destination, except to expand the center.

• Connectors can be first-generation streets that connect distant places. They can be third-generation alleys and through streets that connect side streets.

• Loop streets connect back to the parent street. They may grow from a third-generation cul-de-sac that instead of connecting to another street, loops back to the original street.

Density

Rural

Suburban

Dense

Town Development

Every city starts out as a rural outpost. As the population grows, its density increases. The land becomes valuable, so it makes sense to fill in the space. The outskirts of the city remain rural, like how the city began.

Density Coverage

Density is the average number of units per acre. Distribution is not uniform across space. It is clustered into regions, like groups of houses in a hamlet, or apartments on main street. Houses should be grouped together, so leftover space is large enough to use. When the spacing is uniform, it blankets the landscape with uniform sprawl.

Spatial Networks

Variance exists in healthy communities and other biological systems. Balanced growth naturally distributes itself into towns, cities, and villages. It follows a power law distribution. A high concentration of people (a city) has fewer instances. Half of a metropolitan area's population might be in the city, but there's only one city. There are more towns, but they have fewer people. There are even more villages and hamlets, but they have even fewer people.

gs = geographic size

nd = nodal distance (to parent node)

The example uses 3 as its base, but using the natural log (e=2.718) makes sense. The power law distribution applies to the city itself: the CBD (5%), the downtown area (15%), and the suburbs (80%). For a town: the town center (5%), the main street (15%), and the surrounding neighborhoods (80%).

In the drawing above, road C does not exist because even though villages are worth connecting, the distance between them is not significantly shorter than the existing roads A and B. Street D does not exist because there are natural barriers in the way.

Hubs are central nodes that connect to other nodes. Cities are hubs that connect to towns, which are smaller hubs that connect to villages, which are smaller hubs that connect to hamlets. Spatial networks do not need a direct path from every node to every other node because: 

• It wastes resources to not combine paths.

• It cuts up space to have paths everywhere, and it prevents us from using that space.

• It causes confusion because there are too many intersections, and a decision has to be made at each intersection.

The park has a view of the library, so people will cut the corner to get there, unless there is something in the way. The direct path is necessary, even without the library, because it gets people to the street corner quicker, which has a lot of draw because of everything in that direction.

Building Types

Domestic - four-square building, or a 3x3 (with sub-rooms in the middle), so every main room has corner sunlight. Examples are houses, or an elementary school, or a small office. We can combine units to make larger buildings (i.e. a New England farmhouse that expands over the years).

Institutional - for commercial or civic purposes, or a stately residence, with grand spaces for the public. It has wide entrances, wide hallways, lobbies, high ceilings, columns, large rooms, etc.

Monumental - unique buildings for civic uses, such as a church. The massing is more sculptural and the spaces are designed around the experience.

Miscellaneous - buildings that are specific to their purpose. Examples include technical buildings like an airport, theater, factory, water treatment plant, etc.

Building types exist because they work for multiple uses. We can switch uses without significant changes to the structure. A simple domestic-type building can be an office, a school, a restaurant, or a residence.