2. Site and Environment - NM Flashcards
What does LEED stand for? Who developed the rating system?
Leadership in Energy and Environmental Design;
U.S. Green Building Counsil
LEED rating system (6 concepts)
- Sustainable Sites
- Water Efficiency
- Energy & Atmosphere
- Materials & Resources
- Indoor Environmental Quality
- Innovation & Design Process
How to do a Site Analysis (6 steps)?
- Zoning : property line, setbacks, easements, right-of-way
- Topography & Water: slopes, soil conditions, existing drainage patterns, water table elevation, areas susceptible to flooding / erosion
- Plants: existing trees, water features (wetlands, streams)
- Climate: path of sun, winds, rainfall
- Services: public roads, trains, water mains, sanitary & storm sewers, gas & elec lines
- Existing context: views, noise, history, neighbourhood
Soil profile
Vertical section of soil showing horizons (layers)
Subsurface investigation
Done by geotechnical engineer;
Test pits up to 10’ deep;
Structure of soil, shear resistance & compressive strength, water content, permeability, expected consolidation under loading
Allowable bearing capacity of soil
Maximum unit of pressure a foundation is permitted to impose vertically or laterally on soil
How do we measure soil density?
Standard Penetration Test (number of blows required to hammer soil sampler)
Which types of soil are stable and which are unstable and why?
Coarse grained = stable = low % of void spaces between
Clays = unstable = shrink / expand with changes to moisture content
Shearing strength of soil
Its ability to resist displacement when external forces are applied. Cohesive soils (clay) retain their strength when sloped = angle of repose is steep Granular soils require confinement = angle of repose is shallow
Water table
The level at which the soil is saturated with water
What ground slopes are suitable / not suitable to build on?
25% = erosion, difficult to build on 10% = challenging, more expensive to build on 5-10% = suitable, can be build on 5% = easy to build on
What is a good ecological way to develop a site?
Minimize disturbance
- Do not disrupt drainage patterns
- Include provisions for drainage of surface & ground water
- Attempt to equalize cut and fill on site
- Avoid building on steep slopes - erosion
- Protect wetlands, wildlife habitats
- Avoid floodplains
Effect of : large bodies of water
Heat reservoirs, evaporative cooling effect
Effect of : plant materials
Provide shade, Windbreak, Define space, Screen views, Attenuate Sound, Improve Air Quality, Stabilize Soil
Effect of : grass
Reduce air temperature, stabilize soil, increase permeability of soil
Cool Regions
- Minimize surface area of building - cube shape
- Maximize solar radiation - orient east of south - large south windows, small windows EW, no windows N
- Reduce heat loss - use interior materials high thermal mass
- Provide wind protection
- Dark / medium color materials
Temperate Regions
- Minimize east-west exposure - rectangular shape - orient east of south
- Balance heat gain with shade protection - seasons (heat in winter, cool in summer) - large windows S
- Air movement in hot weather but protect from wind in cold weather
- Medium color materials.
Hot-Arid Regions
- Reduce solar heat gain - cube shape - orient east of south
- Cooling - water features, plantings
- Solar shading for small windows
- Courtyards
- Light color materials - large thermal mass
Hot-Humid Regions
- Minimize east-west exposure - rectangular shape - orient almost full south
- Reduce solar heat fain
- Use wind - evaporative cooling - large openings, high ceilings, cross ventilation
- Solar shading on all openings
- Light color materials - small thermal mass
Different types of passive solar design
- Direct Gain - wdws & thermal floor mass
- Indirect gain: thrombe wall (cocnrete) or drumwall (water pipes)
- Sunspace: solarium
- Roof pond
- Isolated fain : collect & store away from the space
Where should we put windows?
East - west : sources of overheating, difficult to shade
South : can be shaded with horizontal shading devices
North: exposed to winter in cool climates
What is the angle of repose of most soils?
33 degrees
What can make a retaining wall fail?
Overturning, horizontal sliding, or excessive settling
Architectural elements to design of retaining wall?
Drainage - relieves built up water pressure - gravel & weep holes 2”@4’-6’ OR perforated drain pipe
Vertical control joints @ 25’ AND vertical expansion joints every 4th control joint
Batter - backward sloping surface of the retaining wall so it doesn’t appear to be leaning forward
Footing to extend to frostline or 2’ below grade (greater of)
What does the foundation wall do?
- Transfers dead & live loads to the soil.
- Prevents wind-induced sliding, overturning, uplift
- Withstands sudden ground movements of earthquake
- Resists pressure from soil & water
- Counters thrust from tensile structures.
Settlement. What is it and which soils are most susceptible?
Gradual subsiding of a structure as the soil consolidates under loading.
Moist, cohesive clay with large % of voids can consolidate most and occurs slow, over long periods of time
Differential settlement.
Uneven consolidation of the soil.
What type of soil for shallow foundations?
Stable soil of adequate bearing capacity
What type of soil for deep foundations?
Unstable or inadequate bearing capacity
Types of excavation support systems?
Sheet piling
Tiebacks
Slurry wall
Dewatering
Bottom of footing to be at …. of frost line?
12”
What is the most often used foundation wall type?
Strip footings
Catchment Area
the area from which a city, service or institution attracts a population that uses its services.
Proctor Compaction Test
a laboratory method of experimentally determining the optimal moisture content at which a given soil type will become most dense and achieve its maximum dry density.