ACH 121 Lecture 04 (Bldg Site)


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Covers topic of site design and considerations in architectural design. Solar orientation, solar radiation, wind, topography, soil composition, vegetation, water and climate are discussed.

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ACH 121 Lecture 04 (Bldg Site)

  1. 1. The Building Site The building site is the basis to all design. A structure’s design may or may not work with a designated environment.
  2. 2. A design that works for a flat plot of land may not do as well for a sloped topography and vice versus. The Building Site
  3. 3. Therefore a SITE ANALYSIS must be completed first before the progress on the design can commence. The Building Site
  4. 4. Site Analysis is the process of surveying or studying the existing environment and how it will influence the structure’s design and layout on the site.
  5. 5. Environmental forces considered for design are: <ul><li>Geographic location </li></ul><ul><li>Topography (or contouring lines) </li></ul><ul><li>Plant material </li></ul><ul><li>Water </li></ul><ul><li>Climate </li></ul><ul><li>Solar orientation & radiation </li></ul><ul><li>Prevailing winds </li></ul><ul><li>Soil </li></ul>
  6. 6. Other “site” factors for design: <ul><li>Regulatory Factors </li></ul><ul><ul><li>Zoning Ordinances </li></ul></ul><ul><li>Sensory Factors </li></ul><ul><ul><li>Views </li></ul></ul><ul><ul><li>Sounds </li></ul></ul><ul><ul><li>Smells </li></ul></ul>
  7. 7. Geographic Factors <ul><li>GEOGRAPHIC LOCATION </li></ul><ul><ul><li>Different regions of the world require different building types </li></ul></ul><ul><ul><ul><li>North: steep roof slopes and heavy insulation </li></ul></ul></ul><ul><ul><ul><li>East: Moderate roof slopes and all weather construction </li></ul></ul></ul><ul><ul><ul><li>South & West: Flat roof slopes and clay material </li></ul></ul></ul>
  8. 8. Geographic Factors <ul><li>TOPOGRAPHY </li></ul><ul><ul><li>Land forms and ground slopes affect: </li></ul></ul><ul><ul><ul><li>the building foundation type </li></ul></ul></ul><ul><ul><ul><li>the building form and its relationship to the ground plane </li></ul></ul></ul><ul><ul><ul><li>site drainage </li></ul></ul></ul><ul><ul><ul><li>the site’s micro-climate </li></ul></ul></ul><ul><ul><ul><ul><li>wind </li></ul></ul></ul></ul><ul><ul><ul><ul><li>temperature </li></ul></ul></ul></ul><ul><ul><ul><ul><li>solar radiation </li></ul></ul></ul></ul>
  9. 9. Geographic Factors <ul><li>TOPOGRAPHY </li></ul><ul><ul><li>Configuration of surface features of a plot of land </li></ul></ul><ul><ul><ul><li>Shows contour lines which illustrate how the site slopes, grooves & forms </li></ul></ul></ul>
  10. 10. Geographic Factors <ul><li>TOPOGRAPHY </li></ul><ul><ul><li>Contour lines are invisible or imaginary lines in plan view that connect points of equal height above a datum or bench mark. </li></ul></ul><ul><ul><ul><li>Each contour line states the form in which the site acquires over a specified elevation. </li></ul></ul></ul><ul><ul><ul><li>Contour lines are continuous and never intersect each other. They change in shape, but never in elevation. </li></ul></ul></ul>
  11. 14. Contours must match existing grades at the property lines
  12. 15. Geographic Factors <ul><li>TOPOGRAPHY </li></ul><ul><ul><li>By reading the horizontal spacing and shape of the contour lines on a plat, we can determine the nature of site’s topography. </li></ul></ul><ul><li> contour lines spaced far apart indicate a flat surface </li></ul><ul><li> contour lines spaced evenly describe a constant slope </li></ul><ul><li> contour lines spaced closely together designate a steep rise or fall in elevation </li></ul>
  13. 16. Geographic Factors <ul><li>TOPOGRAPHY </li></ul><ul><ul><li>Each contour line is placed with an elevation marker. </li></ul></ul><ul><ul><ul><li>states the height of the contour relative to the site. </li></ul></ul></ul><ul><ul><li>Elevation markers are documented in intervals depending on the size of the plat. </li></ul></ul><ul><ul><ul><li>Smaller sites or sites having gradual slopes may show 1, 2 or 5 feet markers, </li></ul></ul></ul><ul><ul><ul><li>Larger or steeper sites may show markers in 10’, 20 or 50 feet markers. </li></ul></ul></ul>
  14. 18. The Affects of a Slope
  15. 19. The Affects of a Slope
  16. 20. The Affects of a Slope
  17. 21. Geographic Factors <ul><li>SOIL </li></ul><ul><ul><li>The soil type affects: </li></ul></ul><ul><ul><ul><li>the type and size of a building’s foundation system </li></ul></ul></ul><ul><ul><ul><li>the drainage of ground and surface water </li></ul></ul></ul><ul><ul><ul><li>the types of plant material able to grow on a site </li></ul></ul></ul>
  18. 22. Soil <ul><li>All buildings rely on soil for their ultimate support. </li></ul><ul><li>The underlying foundation is effected by the soil’s strength under loading. </li></ul><ul><li>A soil’s stability and strength under loading depends greatly on its resistance to shear. Shear is a function of internal friction and cohesiveness. </li></ul>
  19. 23. SOIL <ul><li>The measure of a soil’s strength is its bearing capacity in pounds per square foot. Factors that determine the bearing capacity of a soil are: </li></ul><ul><li> stratification (class)  composition </li></ul><ul><li> density of soil bed  water </li></ul><ul><li> freezing/thawing  permeability </li></ul><ul><li> variations of particle size </li></ul>
  20. 24. SOIL <ul><li>Most topography consists of superimposed layers of soil, each of which contains a mix of soil types. </li></ul><ul><li>Two classes of soils- </li></ul><ul><li> coarse-grained </li></ul><ul><li> fine-grained </li></ul>
  21. 25. Course-grained SOIL <ul><li>Coarse-grained soils contain gravels and sands that consist mostly of large particles. </li></ul><ul><li>These soils have a low percentage of void spaces and are more stable as a foundation material. </li></ul><ul><li>TYPES: </li></ul><ul><li> cobbles 60mm </li></ul><ul><li> coarse gravel 19mm </li></ul><ul><li> fine gravel 5.5mm </li></ul><ul><li> coarse sand 2.0mm </li></ul><ul><li> medium sand 0.6mm </li></ul><ul><li> fine sand 0.08mm </li></ul>
  22. 26. Fine-grained SOIL <ul><li>Fine-grained soils are just the opposite, containing very small particles; those often that cannot be seen by the naked eye. </li></ul><ul><li>Clay & silt soils tend to be unstable for bearing loads since they shrink and swell considerably with changes in moisture content. </li></ul><ul><li>TYPES: </li></ul><ul><li> silt > 0.08mm </li></ul><ul><li> clay > 0.08mm </li></ul>
  23. 27. Geographic Factors <ul><li>VEGETATION </li></ul><ul><ul><li>The types and locations of plant materials affect: </li></ul></ul><ul><ul><ul><li>the site’s micro-climate </li></ul></ul></ul><ul><ul><ul><ul><li>Solar radiation, wind, humidity, air temperature </li></ul></ul></ul></ul><ul><ul><ul><li>the definition or visual screening or exterior spaces </li></ul></ul></ul><ul><ul><ul><li>the absorption or dispersion of sound </li></ul></ul></ul>
  24. 28. Plant Material
  25. 29. Plant Material
  26. 30. Plant Material
  27. 31. Plant Material
  28. 32. Plant Material
  29. 33. Geographic Factors <ul><li>SOLAR ORIENTATION </li></ul><ul><ul><li>The direction of the sun plays a very important part in how the structure is designed and placed on the site. </li></ul></ul><ul><ul><li>A building’s location, orientation and form should take advantage of the sun’s benefits. </li></ul></ul><ul><ul><li>The objective for locating a building is to maintain a balance between underheated and overheated solar periods. </li></ul></ul>
  30. 34. Solar Orientation <ul><li>Underheated periods are those in which the sun’s radiation is beneficial. </li></ul><ul><li>Overheated periods are those in which the sun’s radiation should be avoided. </li></ul><ul><li>A building’s longest facade should normally face south, with the east and west exposures being warmer in the summer and cooler in the winter than the southern exposure. </li></ul>
  31. 36. The exterior walls and roofing are the building’s PRIMARY shelter against the damaging effects of the sun. However, these items alone cannot fully protect against the sun.
  32. 37. Solar Radiation <ul><li>To reduce the effects of solar radiation, shading devices are used to shield the building’s exterior or interior. </li></ul><ul><li>The effectiveness of these devices depends on their form and orientation relative to the sun’s angles. </li></ul><ul><li>Exterior devices are better than interior devices, because they intercept the sun’s radiation before it can reach the surfaces of the building. </li></ul>
  33. 38. Shading devices graphic
  34. 39. Geographic Factors <ul><li>WIND </li></ul><ul><ul><li>Important site considerations when dealing with wind in all climatic regions: </li></ul></ul><ul><li> wind prevalence </li></ul><ul><li> wind velocity </li></ul><ul><li> temperature </li></ul><ul><li> direction of wind </li></ul>
  35. 40. Geographic Factors <ul><li>WIND </li></ul><ul><ul><li>The wind’s potential effects are considered in the buildings design: </li></ul></ul><ul><li>« daily variations </li></ul><ul><li>« seasonal changes </li></ul>
  36. 41. WIND <ul><li> Wind brings natural ventilation of interior spaces. It aids in the air exchange necessary for health and odor removal. </li></ul><ul><li> Natural ventilation is generated by: </li></ul><ul><li>« differences in air pressure </li></ul><ul><li>« temperature </li></ul><ul><li> Air flow patterns are effected by building geometry. </li></ul><ul><li> Air speed plays little importance. </li></ul>
  37. 42. WIND <ul><li>In hotter regions, particularly ones that are more humid, ventilation is beneficial for convective or evaporative cooling. </li></ul><ul><li>In colder climates, a building should be buffered against cold winds to reduce air infiltration and heat loss. </li></ul><ul><li>A windbreak is used, ie. garden wall or dense trees. </li></ul>
  38. 43. WIND <ul><li> Ventilation of concealed roof and crawl spaces in buildings are required to remove moisture and control condensation. </li></ul>
  39. 44. Other “Site” Factors <ul><li>ZONING ORDIANCES </li></ul><ul><ul><li>Govern the use and bulk of buildings and structures within a community, city or district </li></ul></ul><ul><ul><li> types of activities, which may occur on given piece of land </li></ul></ul><ul><ul><li> how much land can be covered by a structure </li></ul></ul><ul><ul><li> how far the structure must be set back from the property lines </li></ul></ul><ul><ul><li> height and total floor area of structure </li></ul></ul>
  40. 45. Other “Site” Factors <ul><li>SENSORY FACTORS </li></ul>