how are we support or sustain these flow or movements in a city

Flow typesChannel typeCritical utilitiesIntegration and dispersionConsistent characteristics of flow systemGrid patternsRadial patternsLinear patternsDisorderAlignment GrainSuperblocksHierarchies of channelsCapacity of channelsCost of circulation systemRelation to slopePaths and social contactMultiple use of rights-of-wayVisual sequencePath characterWhy hide utilities?Environmental impact of circulation Testing the system

City = a communication net, roads, paths, rails, pipes, & wiresrelated to the pattern of localized activities or land use

Capacity of circulation system - economic & cultural level of a city

Flow types

peoplegoodswastesinformation

_carried in vehicles, on foot, on rails, in the air, in pipes, wires, beltsabove, under, on and above the surface

_total system = substitute for anotherex. telephone calls - personal trips, the flow of gas, bus routes - car trips

_the layout of streets = the pattern of underground utilities, the location of telephone cables

Channel types

_graded & surfaced for pedestrians or wheeled vehicles_rail systems_the wire conveying power and information_the gravity flow sewers drainage_waterborne wastesthe pressure pipes supplying water, gas, steam, bulk material

_the vehicular rights-of-way : the most critical_convey persons, objects_required quality of space

_Layout of roads and walks before the rest of the circulation system

Critical Utilities

_community : water supply - quantity, portability, pressure of waterdisposal of sanitary sewage

_the local : the management of surface drainage

the flow of rain, meltwater, concentration in ditches an wales - flooding and erosion

subsurface structures - the hidden layout chaotic

Integration and dispersion

_well in each house - sewage - disposal plant - nationwide system _electricity - a regional grid or generators

density, topography, function, custom, available facilities

_use integrated road systems, centralized sources of electricity for economy and reliability, central water supply for public health, storm drainage systems

Consistent characteristics of flow systems

_physical circulation organized with terminals and interchanges - networksthe greater the flow, the more elaborate terminals and interchanges from origin to destination

_superhighways, railways transit

a circulation plan - balance without blind reliance on a single mode

_Distribution lines : water, gas, electricity, and telephone lines_small, continuous, flexible, flowing full with valves : interconnected network or web

flows by gravity, storm, sanitary sewers - slopes ; rigid, jointed, large, partially full, branching pattern in plan

channels by self-propulsion : walks, roads, rails, air lanes

_system with source : a well, generator, an outfall, a giant factory - circulation pattern

_systems not interchangeable : pumping water, electric charge

an Origin to a Destinationjoints, moving experience, arrival

Circulation systems - assigned flow, influence on surrounding activities

Gird Patterns

_the networks of channels_Grid : shifting, distributed, easy, clear - suitable for complex areas at large scales

_Criticism : visual monotony, disregard of topography, traffic, lack of differentiation

regularity of interconnectionthe variation of buildings & landscape patternone way : steady-flow systemdifferentiation of paths, occasional interruptionssimple and effective, convenient access, good orientation, suitability for complex distributed flow

Radial Patterns

_channels spread out from a center

a common origin, interchange, destination : water source, sewage disposal, a central telephone exchange, a common workplace, a symbolic center

more direct line of travelhigh trafficrigid systemrings : a radioconcentric net : central flow but allows bypassing movements

problems in local flow and building sites

modification : branching out but difficulty for emergency or delivery vehicles

Linear Patterns

_a single line or a parallel series_activities grouped along the line-direct lines of travel, frontage is used to its maximum.

_railroads, canals, trolley car lines, pioneer agricultural areas

_lack of focus, overloading of the channel

roadtown, a topographic edge

_modification : direct to specialized channels, local flows, minor loops, two continuous paths

_a loop distribution system : electricity, water, residential street

_allows alternate exits and continuous progressive movements for service circulation

Disorder

discourage through movement, adjust to intricate topography, create interest in the street picture

a sense of intimacy, mystery, special character

can be confusing and exasperating

whatever system is chosen must fit into the general pattern of the region of which the development is a part.

Alignment

channels are located along a continuous centerline in 3D, depending on the expected speed, volume, and nature of flow. Standards shifting from place to place, technology, climate, cultural change

conflicting with the fluidity and irregularity of the landscapeHarmonious joint between a tree and a telephone wiresmooth grade between a driveway and a sloping garden

Grain_pattern and arrangement of street blocks and plots

_the degree of specialization of flow and the fitness_greater flow, efficiency sort out trucks, bicycles, children, idle strollersfast long-distance traffic & slow local flow, efficiency of homogeneous flow

_more specialization, less flexibilityIf trucks, cars, pedestrians are separated, then trips will be longer. : a serious obstacle to a readaptation of the environment

Superblock

_a large piece of developable land surrounded by a continuous street

_increase the grain between the circulatory and noncircuculatory zones - improve the amenity of the living areas

_indirect street system, curved to fit the topography, culs-de-sac, minor loops

_50 acres, eliminating street intersections, minimizes expensive street frontage per unit, large and relatively inexpensive interior parks

_loops and culs-de-sac street implanted to separate pedestrian and motor access but attract the pedestrian flow as well, becomes a social focus - branch walks, giving access to the rear of the individual units

_separating car and pedestrian flow not necessarya number of pedestrians are desirable.streets follow the road, merge and divergeSidewalks - footpaths, places for meeting and play

The Pruitt-Igoe Projects

As completed in 1955, PruittIgoe consisted of 33 11-story apartment buildings on a 57-acre (23 ha) site, on St. Louis's lower north side. The complex totaled 2,870 apartments, one of the largest in the country. The apartments were deliberately small, with undersized kitchen appliances. "Skip-stop" elevators stopped only at the first, fourth, seventh, and tenth floors, forcing residents to use stairs in an attempt to lessen congestion. The same "anchor floors" were equipped with large communal corridors, laundry rooms, communal rooms and garbage chutes. The stairwells and corridors attracted muggers. Ventilation was poor, centralized air conditioning nonexistent

March 16, 1972.

The PruittIgoe housing project was one of the first demolitions of modernist architecture; postmodern architectural historian Charles Jencks called its destruction "the day Modern architecture died. Because it was designed by a leading architect and won a "building of the year" award (though no professional awards), its failure is often seen as a direct indictment of the society-changing aspirations of the International School. Jencks used PruittIgoe as an example of modernists' intentions running contrary to real-world social development, though others argue that location, population density, cost constraints, and even specific number of floors were imposed by the federal and state authorities and therefore cannot be attributed entirely to architectural factors.

http://en.wikipedia.org/wiki/Pruitt%E2%80%93Igoe

Hierarchy of channels

_increase and decrease the grain of circulationcenters with intense flow grading to low specialization

_total system with hierarchy system

_cul-de-sac - minor streets - the collector street built for heavy flows - service road - freeway

Interchange

_flows are intense, channels are specialized, and trips are multimodal_delays & conflicts - the chief losses in the system - further specialization or force the distribution and reduction of termini

Interchange

_how best to enter a building when arriving by car_deceleration_storage capacity_esthetic problems of a change of scale and a danger of isolating the entrance

_clear orientation and a visual transition between velocity and repose

Parking may be dispersed, placed in separate levels, or threaded with lines of activity or landscaping that afford an inviting pedestrian access.