Reading Notes Flashcards
The Grid System
Consist of Equally spaced streets or roads which are perpendicular to each other. This system is often used because of its regularity, simplicity and convenience.
The Radial System
Directs flow to or from a common center, with straight channels of circulation radiating from this center point. A series of by-passes connecting outlying radial can be created, thereby allowing through traffic to skirt the center alleviating congestion.
The Linear System
Connects flow between two points, either along single line or along a series of parallel lines.
The Curvilinear System
Response to the topography of land and aligns with natural contours.
Freeway (Expressway)
Designed to allow movement of large volume of traffic between, around or though urban centers.
Arterial Streets
Continuous vehicular channels that connect to expressways by means of on-off ramps at carefully determined locations. Parking is normally not allowed. Intersections should be separated by at least 800 ft
Collector-Distributor Streets
Serve as the transition between arterial street and the local access streets of neighborhoods. These streets are frequently discontinuous , thereby preventing through traffic.
Local Access Streets
Provide access to low-intensity uses fronting on them. they carry low traffic flows.
Broken-Back Curves
Two curves in the same direction and should be separated by a tangent not less than 200 ft.
Reverse Curves
Two curves in opposite directions and should be separated by a tangent not less than 100 ft.
Compound Curves
Two curves in the same direction with different radii. This should be avoided altogether
Simple Curves
A circular arc connects tangents at each end. may employ tangents of an length.
Acute angle intersection
the intersecting streets are less than 80 -85 degrees should be avoided because it is difficult to negotiate and limits driver visibility.
Cul-de-sac
should not exceed 400 ft. A minimum turnaround at the end of a cul-de-sac should be provided which is at least 80 ft in diameter and free of parking.
Loop Street
Max depth is 700 ft
Block
Max length of a block is 1,600 ft
Curb Radii
Minor street - 12 ft min.
Major street - 50 ft min.
Traffic Signal Required
750 vehicles per hour
Grade Separation required
3,000 vehicles per hour
most common is cloverleaf (based on a system of right turns)
Diamond Intersections
Used when expressways intersect secondary roads
Cartridge Roads
on-site loop distributor and collector drive with carefully located access points to the local road system ( Large Shopping Centers)
Pedestrian movement
a total of 13 sq ft per person is required to move easily without making body contact.
if less than 7 sq ft, pedestrians tend to move as groups rather than individuals.
Primary objectives of good pedestrian circulation
safety, security, convenience, continuity, comfort, and attractiveness.
Wheelchair restrictions
Min turning clear space is 5’
Min passing width for two wheelchairs is 5’
walks should not a gradient greater than 1:20(5%) with a max cross gradient of 1:50 (2%)
Curb Cutouts
Should be identified by a 1/16 inch yellow abrasive anti-slip epoxy finish applied to the entire area of the curb cutout.
Ramps
should not exceed 1:12 (8 1/3%) preferably 1:16 (6 1/4%). Ramps should be min. of 3’ wide and not exceed 30’ in length. Handrail should be located at each side of ramp if rise is greater than 6” or its run I greater than 72”.
Utilities and services
Include: water, gas, electrical, communication systems, wastewater systems, drainage systems, and flood control…
The space beneath the public street right-of-way is the most logical and efficient location.
underground utility location general principles:
- wastewater lines, because of their gravity flow requirements, should have first priority.
- Trunk (main) lines should not be located in major traffic arteries, if possible
- trunk lines for several utilities should not be located in the same street
- the center of streets should be reserved for the wastewater line, unless the street in sufficiently wide to accommodate a dual water system
5’ all utility installations required for the next five years should be installed before a street is paved.
Water main sizes
Often determined by fire protection requirements, are generally 6” in typical residential and 8” in high density districts.
Fire hydrants
urban - 150’
suburban - 600’
Force main
We wastewater is pumped over extensive horizontal distance
Wastewater mains
Lowest structure below street level.
velocities no less than 2.5 feet/second and no more than 10 feet per/second
Microclimate
Local conditions that effect climate such as: topography, structures, exposure, ground cover, elevation and body of water
Comfort zone
A narrow range of related conditions including temperature(65-75), humidity (30-60), air movement, and air quality.
Sun Control
Southerly latitudes- shorter overhangs for high angled sun
Northerly latitudes - longer overhangs for low angled sun
U Value
Measure of heat transmission which is the number of BTU per hour that pass through one square foot of wall or roof.
a low U value indicates slow heat loss or gain while a high U value indicates rapid loos or gain
Thermal Inertia
The ability of a material to store heat
Hydrologic Process
Water cycle. Falls as precipitation, then follows three paths - runoff, infiltration, transpiration. (evaporation)
Purpose of a Detention pond
To hold water during a heavy rain fall, then be slowly release without causing flooding. Flow to rain water from new development be equal to the runoff from the site prior.
Ground water table
Boundary between the two zones (Aeration/Saturation)
Aeration Zone
Higher zone - Space between the soil grains contain both water and air.
Saturation Zone
Lower zone - Space between the soil grains only contain water
Soli types
- Bedrock - forms the earths crust (Strongest Support)
- Slate and Shale - fine-textured soft rock
- Boulders - rock detached from the bedroom
- Decomposed rock - Disintegrated rock masses that were originally solid
- Hardpan - mixture of gravel , clay and sand( good for foundations)
- Gravel - granular rock particulars ranging in size from 1/4” - 3 1/2” (any rock larger are called cobble-stones)
- Sand - loose granular rock particles .002”-1/4”
- Silt - Fine grained sedimentary material deposited from running water(when formed with water = mud)
- Clay - fine grained cohesive material formed from decomposition ( least stable soil, swells when water and shrinks when dry)
Test pit
Simple excavations that permit direct visual inspection of the actual soil conditions (generally not dug below the water table)
Soil load test
A platform is erected on site and incremental loads are applied .
Auger Boring
Auger boring brings up soil samples be means of an ordinary 2 0r 2 1/2” auger fastened to a long pipe. usually stops at the first obstruction. (50 ft)
Wash borings
2-4” pipe driven into the soil and contains a smaller jet pipe through which water is forced. the material washed up is often thoroughly mixed thus reducing the dependability ( also boulders can be mistaken for bedrock) (100ft)
Core boring
Most reliable. can penetrate all materials and bring up complete cores of the materials.
Soil Propeties
Specific gravity Grain size Grain shape Liquid and plastic limits Water content Void radio unconfined compression
Slope guidelines
Grassy recreational areas - 3%
walks adjacent to building - less than 4%
parking areas - less than 5%
Streets used by vehicle - less than 10%
Measuring ground slope
h = horizontal distance v = vertical distance g = grade g = (v/h)x100
Column footing
Square/ Rectangle pad that spreads the column load
wall footing
Continuous spread footing; spreads the load of a wall
Combined/cantilever footing
When footing abuts the property line, combined footing used that connects the exterior column footing to the first interior column footing
mat footing
(Raft footing) one large footing under the entire building. used when soil conditions are poor.
Boat footing
Similar to mat footing, except that it is placed at a depth such that the weight of the soil removed is equal to the load of the buildings, and thus little or no new lad is added to the underlying soil.
Drilled pile
Transfers load by friction
Drilled caisson
Transfers load by end bearing
Cofferdams
used for bridge piers located in water. entire area is surrounded by a watertight sheet piling, water is pumped out and the foundations are the constructed
Slurry wall
Trench is filled with a slurry mixture of bentonite clay and water which resist the pressure of the earth. after the trench excavation is complete, steel is lowered in the trench and concrete is placed from the bottom up while the slurry in pumped out.
Bracing
Used to brace the sheeting to resist soil pressure. diagonal braces called rakers. Rakers can interfere with the excavation though.
Underpinning
supports existing foundations or walls being extended downward to the level of new deeper foundation. (needle beams or pip cylinders with hydraulic jacks)
Types of asphalt
Asphaltic Concrete
Cold laid asphalt
Asphalt macadam
Cost Control
pg. 73
1. Locate buildings along gently sloping terrain.
2. Locate buildings were positive natural drainage exists
3. Arrange vehicular circulation systems on the site to follow contours
4. Locate paved parking lots on relatively level ground
5. Locate buildings so they relate to new and existing utilities
6. locate site improvements to utilizes existing vegetation
7. avoid locating improvements over rock, organic soil or areas of high water table
8. Coordinate the location of new with existing facilities
9. select appropriate finish material for site improvements
10. select indigenous plant material for landscaping
11. select lighting systems in consideration of capitol, energy, replacement and labor cost
Model land development code
recognized aesthetics, environmental problems and the preservation of historical sites.
Flexible Zoning
Planned use development (cluster concept), Floating zone, Incentive (bonus) zoning, and contact zoning
Variances
Exceptions to zoning and ordinances
The Natural Step
Organized by scientist, designers and environmentalist in 1996. Concerned with the preservation of the thin layer that supports human life - Ecosphere ( five miles of the earth’ crust and biosphere ( five miles into the troposphere of the atmosphere
The Natural Steps Principles
- Elements from the earth such as fossil fuels, ores, timber etc. must not be extracted from the either at a great rate than they can be replenished.
- Manufactured materials cannot be produced at a faster rate than they can be integrated back into nature.
- People must preserve the variety of living organisms that exist.
- human needs must be met in the most environmentally sensitive way possible
5.
Sustainable Site planning an Design
- Site selection
- Alternative Transportation
- Reduction of Site disturbance
- Storm Water management
- Ecologically sensitive Landscape
- Reduction of light pollution
- Open space preservation
Sustainable site selection
- Adjacency to public transportation
- out of floodplains
- Avoid site prone to erosion, landslides and fires
- Avoid site with high slopes or agricultural use
- locate with Solar orientation and wind patterns in mind
- locate with landscape site conditions in mind
Storm water management
- Provide on-site infiltration of contaminants from entering the main waterways . use swales filled with wetland veg. is a natural filter
- Reduce impermeable surfaces and allow local aquifer recharge instead of runoff to waterways
- Encourage groundwater recharge
Ecologically sensitive landscaping
- Use indigenous planting
- Locate shade trees over dark surfaces to reduce heat-island effect
- replace lawns with natural grasses
Ahwahnee Principles
A group of architects, planners and community leaders met to present community principles that express new, sustainable planning ideas
Community Principles
Regional Principles
Implementation Principles
Ahwahnee Principles (Community)
- All planning should be in the form of complete and integrated communities containing housing, shops, workplaces, schools, parks, and civil facilities essential to the daily life of the resident.
- Community size should be designed so that housing, jobs, daily needs and other activities are within easy walking distance from each other.
- As many activities as possible should be located within easy walking distance of transit stops.
- A community should contain a diversity of housing types to enable citizens from a wide range of economic levels and age groups to live within its boundaries.
- Businesses within the community should provide a range of job types for the community’s residents.
- The location and character of the community should be consistent with a larger transit network.
- the community should have a center focus that combines commercial, civil, cultural and recreation uses.
- The community should contain an ample supply of specialized open space in the form of squares, greens and parks whose frequent use is encouraged through placement and design.
- public spaces should be designed top encourage the attention and presence of people at all hours of the day and night.
- Each community or cluster of communities should have well-defined edges, such as agricultural greenbelts or wildlife corridors, permanently protected from development
- streets, pedestrian path and bike paths should contribute to a system of fully connected and interesting routes to all destinations. their design should encourage pedestrian and bicycle use by being small and spatially defined by buildings, trees, and lighting and discouraging high speed traffic
- wherever possible, the natural terrain, drainage, and vegetation of the community should be preserved with superior examples contained within parks or greenbelts
- the community design should help conserve resources and minimize waste.
- communities should provide for the efficient use of water through the use of natural drainage, drought tolerant landscape and recycling.
- the street orientation, the placement of buildings and the use of shading should contribute to the energy efficiency of the community.
Ahwahnee Principles (Regional)
- The regional land-use planning structure should be integrated within a larger transportation network built around transit rather than freeways
- regions should be bounded by and provide a continuous system of greenbelt/wildlife corridors to be determined by natural conditions
- regional intuitions and services (government, stadiums, museums and so forth) should be located in the urban core.
- material and methods of construction should be specific to the region, exhibiting a continuity of history and culture and compatibility with the climate to encourage the development of local characters and community identity.
USGBC
U.S. Green Building Council
LEED
Leadership in Energy and Environmental Design; sponsored by USBGC
Life-Cycle costing
Not only the initial cost, but the operating, maintenance periodic replacement and residential value of the design elements.
Five goals of sustainable design
- use less
- recycle components
use easily recycled components - use fully biodegradable components
- do not deplete natural resources necessary for the health of future generations
Leed Categories
- Sustainable site
- Water efficiency
- Energy and Atmosphere
- Material and resources
- indoor air quality
- Innovation and design practice
Innovative technologies
- Ground water aquifer cooling and heats (AETS)
- Geothermal Energy
- Wind Turbines
- Photovoltaic System (PV)
- Fuel Cells
- Biogas
- Small-scale hydro
- Ice storage cooling system
