John Seitz, RA, LEED AP Assistant Adjunct Professor Professor Paul C. King, RA, AIA, ARA Assistant Professor Geology Geology is the scientific study of the structure and composition of the earth s surface Kaaterskill Falls, Catskill Park, NY, image credit John Seitz 2011 1
Geology Building design requires a basic knowledge of geology to understand the characteristics of the site, to design adequate foundations, support plant communities, guide water flows and ensure resiliency. We consult civil engineers for drainage, and structural engineers for building foundations. Monastery in Bhutan Plant Communities and Soil SELECTION & BOUNDARIES ANALYSIS and MAPPING PROGRAMMING and INTEGRATED DESIGN CLIMATE PRODUCTIVITY & BIODIVERSITY MAINTENANCE INTRO TO TERM PROJECT NEXT CLASS Rain Forest Savannah Temperate Forest Natural plant communities are determined by and determine climate and soil. 2
Extensive green roof SELECTION & BOUNDARIES ANALYSIS and MAPPING PROGRAMMING and INTEGRATED DESIGN CLIMATE PRODUCTIVITY & BIODIVERSITY MAINTENANCE INTRO TO TERM PROJECT NEXT CLASS Green roofs are a microcosm of the larger environment and for diverse plantings a variety of soil depths and types are often required. Intensive green roof Rocks There are three types of rocks: Sedimentary Igneous Metamorphic 3
Rocks - Sedimentary Rocks formed by the deposition of transported sediments. This type of rock is formed by particles which have been transported by streams, ocean currents, ice or wind. The particles could be sand, dirt, rocks or even skeletons, shells and parts of living creatures. The rock is laid down in layers and the most beautiful is often considered to be limestone. Rocks - Sedimentary Lithification is the process by which deposited sediments are converted to firm rock. This type of rock covers most of the earths surface. Examples are sandstone shale limestone 4
Rocks - Sedimentary Sandstone composed of sand-sized mineral particles Shale most common - made from mud, clay and silt-sized mineral particles Limestone composed primarily of calcium carbonate minerals of marine origin Rocks - Igneous Igneous rocks are formed when molten rock material cools and solidifies on or beneath the earth s surface. It is hard, dense and strong with very high bearing capacity. Granite 5
Rocks - Metamorphic Rock formed from igneous or sedimentary rock as a result of heat, pressure, and chemical action. Metamorphism is the process by which igneous or sedimentary rock is converted to metamorphic rock. It occurs mainly in mountainous areas. Rocks - Metamorphic Foliated arrangement of minerals in parallel layers along which the rock easily splits into thin flakes or slabs. Slate Schist Gneiss 6
Fordham Gneiss beneath Belvedere Castle, Central Park, image credit Stig Nygaard 2005 Manhattan Schist, Edgecombe Avenue, image credit John Seitz 2010 Rocks - Metamorphic Unfoliated metamophic rocks include: Quartzite Marble 7
Inwood Marble outcrop, Isham Park, image courtesy of http://www.newyorknature.net/geology.html Soil Soil is a living matrix and an essential part of the ecosystem. It is also a building medium, mineral in content and formed over thousands of years. It varies greatly in character based on parent rocks, climate, topography, age and the actions of plants, winds, and water. Soil section from Derek Elsom s, Earth, The Making, Shaping and Workings of a Planet, 1992 8
Soil Horizons Soil is divided into horizontal layers called horizons. The three main soil horizon layers are the A, B and C layers. Soil - A Horizon The layer called topsoil; Seeds germinate and plant roots grow in this dark-colored layer. It is made up of humus (decomposed organic matter) mixed with mineral particles. 9
Soil - B Horizon Also called the subsoil It contains clay and mineral deposits (like iron, aluminum oxides, and calcium carbonate) that it receives from layers above it when mineralized water drips from the soil above. Soil - R Horizon The unweathered rock (bedrock) layer that is beneath all the other layers. 10
Soil Classification There are many different ways of classifying soil based on its uses. From a building perspective we are most interested in systems based on particle size since that largely determines 3 important soil qualities: Drainage Bearing Capacity Erodibility Soil Classification USDA Classifications Sand Silt Clay We also look at Gravel Organic Soils 11
Sand Sand is a coarse grained soil whose particles are.002 to.25 inches in diameter Silt Silt is a fine grained soil whose particles are.002 to.00008 inches in diameter 12
Clay Clay is a fine-grained soil whole particles are smaller than.00008 inches in diameter Gravel Gravel is a coarse grained soil whose particles are larger than.25 inches in diameter. It has good to excellent drainage characteristics and bearing capacity. 13
Organic soils Organic soils are much more important to supporting life than buildings. They generally retain water and have very low bearing capacity. Unified Soil Classification System 14
Soil Investigations A Test pit is an excavation made to expose the subsurface soils for an in-place examination Soil Investigations Test boring is a hole drilled into the ground, from which samples or undisturbed subsurface soils are obtained for laboratory inspection and testing 15
Soil Investigations A soil boring log is a graphic representat ion of the soils encountere d in a test boring. Soil Investigations Bearing Capacity is the ability of a soil to support a structural load. 16
From Wild New York, Mittlebach and Crewdson, 1997 Surficial Geologic map (soils) NYS Geological Survey 1989 Geologic map (bedrock) NYS Geological Survey 1970 17
Surficial Geologic map (soils) NYS Geological Survey 1989 Geologic map (bedrock) NYS Geological Survey 1970 18
Foundation problems may be caused by.. Subsidence Previous building foundations Changes due to moisture Seasonal changes Subsidence Subsidence is the sinking of the land which may occur because of poor compaction, decomposition of organic fill, or the removal of subgrade materials through mining (oil, gas, minerals, water). 19
Previous building foundations Foundations must rest on undisturbed soil. If a building was previously on the site, the new foundation must go below the level of the old foundations. Changes due to moisture Expansive soil Refers to clay which swells when wet and shrinks when dry. 20
Seasonal Changes In the winter, soil freezes and expands. In the summer, the soil contracts. Frost line is the deepest penetration of frost below grade. Foundations must be below this level. Methods for overcoming poor bearing capacity Compaction is the reduction of soil volume by pressure from grading machinery. Piles rely on the support of friction. The foundation may go down to bedrock. 21
For next week The team PowerPoint presentations for both classes will be posted on the openlab website for everyone to review. Each student is required to make at least two comments on the work of two other teams (that is two comments one for each team) You must make comments on a team that is focused on a different category than your own and you can comment on the work of either class. As the semester continues you must continue two comments per week until the end of the semester. In addition each team must respond to any comments left by other students. The purpose of this is to create dialogue and for everyone to be familiar with the efforts and work of other teams. Remember this is a class project with a final class presentation. http://store.usgs.gov/b2c_usgs/usgs/maplocator/(xcm=r3standardpitrex_prd &layout=6_1_61_48&uiarea=2&ctype=areadetails&carea=%24root)/.do 22
http://store.usgs.gov/b2c_usgs/usgs/maplocator/(xcm=r3standardpitrex_prd &layout=6_1_61_48&uiarea=2&ctype=areadetails&carea=%24root)/.do 23