Structural Principles and Landscapes Over Structure GSD 6242 Ecologies, Techniques, Technologies IV Spring 2015Niall Kirkwood FASLA Alistair McIntosh FASLA

The Diagnostic Section has Material, Constructional and Structural Implications

Vocabularies of Construction have Structural Properties Boundary: Walls are Vertical Panel Structures Surface: Paving Systems are Horizontal Slab Structures Surface Transition: Stairs, Retaining Walls & Perrons are Beams Object: Tents are Membranes, Bridges & Pergolas are Frames, Rennie & Canvas Shade Structures are Hybrids

1.0 Materials and Landscape Structures Carry Loads Types of Loading: 1.1Dead Load is the self weight of the materials of a structure 1.2Live Load is the temporary applied load created by the use of the structure such as people dancing on a deck or snow load on a pavilion roof 1.3Thermal Load is the internal load created in a material or structure by temperature changes and the consequent expansion and contraction of a material or structure 1.4Dynamic Load is the temporary applied load created by wind or similar temporary effects All Structures are designed to accommodate the worst combination of theses four loading categories

2.0Materials and Structures Move to React to Loads 2.1It is by deflecting that materials and structural configurations develop resistance to applied loads This resistance to applied loads limits further deflection and when the applied loads are removed the material or structure returns to its original dimensions and configuration The applied loads flow along load paths through the elements and joints of a structure to the foundations where the sum of loading action and foundation reaction equals zero and achieves equilibrium

3.0Loading Induces Tensile & Compressive Stresses in Materials and Structures. 3.1 Tensile Stress lengthens a material or structural element 3.2 Compressive Stress shortens a material or structural element 3.3The change in length of a material or structural element under load induced stress is called Strain TensionCompression

4.0 There are Landscape Structures that are Composed of Simple Tension and Compression Elements. Steel Cable Pergola in Tension Standing Stones in Compression

5.0 Most Landscape Structures are Composed of Elements Subject to Combinations of Tension and Compression in Four Loading Conditions. Bending Shear Torsion Buckling

Bending Cantilever Bending Shear Torsion Column Buckling Beam Buckling 5.1 Loading Conditions

Simply Supported Beam Double Cantilever Beams 5.2Loading Influences Efficient Structural Shape: Bending Moments

Shear Web Torsion Resistance 5.2Loading Influences Efficient Structural Shape: Shear & Torsion

Column to Roof Beam Moment Connections Reduce Buckling and Allow Thin Columns. 5.2Loading Influences Efficient Structural Shape: Buckling Diagonal Struts Prevent Deck Beam Buckling

6.0Structural Properties of Materials 6.1The structural properties of materials determine their efficient structural shape and use in landscape details and landscape structures Strength is a measure of the load per unit area a material can resist - stress Stiffness measures the deformation of a material per unit of length – strain Ductility is a measure of the ability to substantially deform under stress before failure Brittleness is a property where a material fails without significant deformation Elasticity is the ability of a material to return to its original shape after a normal load is removed Creep is the permanent deformation of a material under long term loading

6.2Steel Beam in Compression Steel Cable in Tension Compression Cord Tension Cord

7.0Pergola: Structural Understanding

8.0Landscape Over Structure: A River Pier

Top Soil Structural Soil Filter Fabric Drainage Fill Rigid Insulation Protection Board Waterproof Membrane

8.0Landscape Over Structure: A River Pier

8.1Landscape Over Structure: Extensive Green Roof

8.2Landscape Over Structure: Hybrid Green Roof

9.0Stair