PA/PPD Site Development: Soil-Drainage-Foundation
Types of boring tests
Auger borings Core borings Wash borings Dry sample borings
How to divert subsurface water away from a building's foundation
Drain tile/French drain (perforated pipe) system
Permeability
Drainage rate
Overconsolidated soil
Historical compression (soil memory)
Common soil problems
Inadequate bearing capacity Subsurface water Shrinkage Slippage Seismic forces Frost heave
Excavation slope support systems
Shoring Slurry walls
Foundations and underconsolidated soil
Short and long term settlement
Grass slope parameters (drainage)
Should not exceed 25%
Soldier beams and lagging
Steel columns (soldier beams) driven into earth with lagging (wood planks) fastened to it.
Runoff
Storm water that does not seep into the ground Must be drained away from buildings, roads, and other areas of activity
Gravel
Particles over 2mm in diameter Excellent for construction loads, drainage and sewage drain fields Unsuitable for landscaping
Clay
Particles under .002 mm in diameter. smooth and floury when dry, plastic and sticky when wet Expansive = poor for foundations High porosity/low permeability = poor drainage = bad for landscaping and drain fields High porosity Low permeability
Pile caps
Thick reinforced concrete blocks that distribute the load from the column to the (deep) foundation.
Waterstop
Used between the slab on grade and the foundation wall to seal the joint against water penetration Rubber/neoprene
Specific gravity (soil)
Used to determine void ratio
Water table
The level below which all soil is saturated with groundwater
Abrasion resistance grades (pavers)
Type I Type II Types III
Factors to consider when designing footings
Unit loading Shear Bending
Deep wells (dewatering)
Used to lower water table more than well points (100' or more). ACTIVE.
Benched excavation
Utilized when site is larger than the area to be covered by the building.
Soil bulk density
Weight/volume of any unit of soil
When to use testpits
When foundation is not expected to extend deeper than 16'
Characteristics of PVC pipe
Widely used High strength Lightweight Low cost Easy to work with Durable Nearly all wastewater sewers Environmental concerns in manufacturing Difficult to recycle
Typical pile materials
Wood Steel Concrete Composite
BEES model evaluates what 10 impacts
global warming potential acidification potential eutrophication potential (excess nutrients) natural resource depletion indoor air quality impacts solid waste impacts smog ecological toxicity human toxicity ozone depletion
shear resistance
resistance to sliding
Aeolian soils
transported and deposited by wind Typically silt or sand-sized soils
Infiltration trench (characteristics)
2' - 10' deep (depth to be coordinate with bedrock/water table) Trench is lined with filter fabric and stone Observation well should be installed in trench to monitor sediment and dewatering Idea for small drainage areas
Infiltration basin
A depression used to detain stormwater for short periods of time until it percolates to the groundwater table (similar to detention basin) Suitable for larger drainage areas and water is stored in a visible surface pond Offsets the increase in runoff from the developed site Designed according to infiltration trench parameters
Radon
A naturally occurring radioactive gas
Construction of needle beam support
A series of holes (5 - 10') apart are made in wall. Steel beams are placed thorugh them and supported on mud sills or blockings.
Brownfields
Abandoned or underutilized properties that are contaminated or perceived as being contaminated
Types of dampproofing
Admixtures Bituminous coatings Cementitious coatings Membranes (typically used for waterproofing) Plastics
Design strategies when water soluable pollutants are at risk
Algae in wet ponds Microorganisms in wetlands Biorentention beds Rain gardens
Steps to restore vegetative cover (landscape restoration)
Allow for soil analysis Select plants that will stabilize and revegetate, must be able to reestablish quickly Add acrylic polymers to soil Sod can sometimes be utilized Use trees for long term success
Grading
Alteration of a site's contours.
Examples of vapor barriers
Aluminum foil Sheet plastic Asphalt saturated felt
Soil porosity
Amount of pore space in a soil Relates to grain size distribution and consolidation
Relative humidity
Amount of water vapor air contains/maximum it can contain
Formaldehyde
An air pollutant that is a colorless chemical used to manufacture building materials and many household products, such as particleboard, hardwood plywood paneling, and urea-formaldehyde foam insulation.
Drain inlet
An opening in the ground that allows stormwater to run directly into the storm sewer; opening is covered with a metal grate
Catch basin
An underground reservoir that has a sump built into it. Debris settles into the sump instead of flowing down the sewer
Damproofing
Applied to a foundation wall when hydrostatic pressure from the groundwater table will not occur Typically applied in liquid form (brush/spray) Applied to each contacting surface of foundation Used below grade
Wetlands (characteristics)
Areas inundated/saturated by water often enough and long enough to support vegetation that has adapted to this condition Great deal of biodiversity 18 - 24" of saturation
Characteristics of liquefication
Associated with earthquakes Soil loses bearing capacity Fine and medium grained sands, silts in loosely packed layers Denser the soil, the lower the liquefication risk
Sources of asbestos
Attic and wall insulation Vinyl floor tiles and backing Roofing, siding, shingles Textured paint and patching compound Walls/floors adjacent to wood burning stoves PIpe insulation Oil and coal furnace gasketing
Methods of mitigating liquefication in seismic zones
Avoid locations where potential for ground failure has been identified Compact the soil Change the soil Dewater the site
Methods of measuring building performance
BEES model (EPA and HUD) ASTM LEEd
Health issues caused by lead exposure
Behavioral/learning problems Hearing problems Anemia Cardiovascular issues Increased blood pressure Decreased kidney function Reproductive issues
Sources of formaldehyde exposure
Breathing in off-gassed formaldehyde
Well points (dewatering)
Can lower water table 15' (less than deep wells) vertical pipes with screen openings inserted into ground and water pumped away from construction site. PASSIVE
Health issues caused by dioxin exposure
Cancer Reproductive issues Developmental problems Compromised immune system
Concerns with treated lumber
Cannot come in contact with people, animals or groundwater Disposing of treated lumber is difficult Not waterproof, guards against insects only
Permeable (watertightness)
Capable of being penetrated by water without causing rupture or displacment
What determines bearing capacity of soil
Code Testing
Storm drains
Collect water from roof downspouts, drain inlets, catch basics and drain tiles surrounding the building foundation
Waterproof
Completely impervious to water, whether under pressure or not
Rainwater collection system
Composed of a water collection system, storage cistern and a water distribution system
Impact of increased dead loads on structure on soil
Compresses soil beneath footings >> reduces void volume >> settlements
Popular materials for pond construction
Concrete Geotextiles Plastics Fiberglass prefab pools
Foundation wall materials
Concrete, CMU, wood
3 methods in which heat is gained or lost in buildings
Conduction Convection Radiation
Pile load test
Confirms design loads on pilings
Hardpan
Consolidated mixture of gravel, clay and sand. Good foundation base for buildings
High water table's impact on construction
Construction excavation must be braced/kept dry with pumping Basements must be waterproofed; walls designed to resist hydrostatic pressure Underground tanks must be designed to resist uplift Bearing capacity of soil is typically reduced
Site characterization contains what information
Contains geotechnical analysis of subsurface conditions: Depth to bedrock Depth to groundwater High water table Specific soil tests
Benefits of native plantings
Contributes to biodiversity Reduces/eliminates need for pesticides and fertilizers Reduced maintenance costs (requires less care) Increase/improve habitat
Incineration (brownfield)
Controlled burning of soil or solids to convert, degrade or oxidize contaminants. May be done on or off site
Exposure to radon
Cracks in solid floors Construction joints Cracks in walls Gaps in suspended floors Gaps around service pipes Cavities inside walls water supply.
Benefit of deconstruction
Creates more jobs and business opportunities than demolition
Symptoms of foundation failure/differential settlement
Distorted building frame Sloping floors Walls/glass crack Doors and windows inoperable
Causes of asbestos exposure
Disturbance of asbestos containing material Released into the air.
Deflectors (streams)
Divert flow Deepen a channel
Methods to increase bearing capacity and/or decrease settlement of soil
Drainage/dewatering Fill compaction Densification Surcharging Mixing Geotextiles Deepening or increasing the bearing area of footings Remove soft/organic soil and replace with granular materials (expensive) Cover compressible soil with porous layer of sand, gravel, crushed rock.
Detention basin
Dry basin that only fills with water when it rains Releases water at a pre-development flow rate via an outlet
Stormwater infiltration and recharge methods
Dry wells Filter Strips Sand filters Infiltration trench Infiltration basin Rain gardens
Standard pipe materials
Ductile iron or steel ABS Cast Iron Concrete HDPE PVC Vitrified Clay pipe
Characteristics of cast iron pipe
Durable Low thermal expansion No more durable than PVC High energy and environmental impacts
Earth movement and clay subsoils
Earth movement more likely to occur due to expansion and contracting of soil.
Where are PCBs found?
Electrical heat transfer and hydraulic equipment Plasticizers in paint Fluorescent light ballasts Cable insulation Oil based paint Caulking Plastic Floor finish
Swales
Encourage infiltration Reduces the velocity of water Less expensive than pipes Easy to maintain More natural approach than curb Use geotextiles in areas with greater velocities
Conduction
Energy is transferred by direct contact (touching a hot stove)
Convection
Energy is transferred through a medium-- liquid or gass-- caused by molecular motion (boiling water)
MX durability grade
Exterior grade
Foundation depth (frost 12"+)
Foundation/basement beneath frost depth
Relationship between foundations and expansive soils
Foundations must be isolated from them. Utilize deep foundations (piles or caissons) that bear on material below the expansive soil Utilize concrete grade beams
Two methods of relieving hydrostatic pressure around a building structure
Gravel drain (difficult to do) Drainage mat
Sanitary sewer (characteristics)
Gravity flow most common Flow calculated by using peak flow Pipe diameter < 8" Regularly spaced manholes
3 Types of retaining walls
Gravity wall Cantilever wall Counterfort wall
Environmental risks (high)
Habitat alteration Species extinction Overall loss of biodiversity Stratospheric ozone depletion Global climate change
Water-resistant
Having no openings larger than capillary pores that permit leakage of water
Characteristics of concrete pipe
Heavy and expensive to install Durable Useful when significant loads are required
Environmental risks (medium)
Herbicides/pesticides Oil spills Toxins, nutrients Biochemical oxygen demand Turbidity in surf Acid deposition Airborne toxins
Relationship between temperature and water vapor
High temperatures can hold more water vapor
Direction in which water vapor moves
High to low pressure (inside to outside, climate depending)
Needle beams
Horizontal beams inserted through a foundation or pier, which transfers the loads to adjacent soil.
Key global climate changes
Increase in carbon dioxide World's oceans are becoming warmer Rising ocean levels (thermal expansion and glacier runoff) results in erosion and floods Oceans more acidic due to more carbon dioxide Increase precipitation and droughts Increase in plants (due to more carbon dioxide)
Relationship between global warming and cooling costs
Increase in global warming results in an increase in cooling costs
Negative side waterproofing installation
Installed on side not exposed to water
CERCLA
Landowner is liable for environmental conditions whether they know about it or not-- cost of cleanup, damage to 3rd parties
Type III Abrasion resistance grade
Least resistant Residential or light duty patios
Treatment of asbestos
Leave undamaged asbestos alone Repair: seal/encapsulate Remove
Characteristics of ABS pipe
Lighter than PVC More expensive than PVC Twice thermal expansion of PVC MFR involves a number of toxic materials
Alluvial soils
Loose, saturated soils transported and deposited through action of flowing water Unsuitable for foundations
Bioremediation (brownfield)
Microorganisms used to degrade organic compounds in soils or groundwater. May be done in situ or ex situ.
Plastic limit of soil
Moisture content at which soil loses its plasticity and begins to behave like a solid.
Moisture problems in soil derive from
Moisture leaks into a building via capillary action or hydrostsatic pressure Precipitation Water vapor in the air
Plastic soil
Moldable when wet
Membrane waterproofing
Most common Several layers of asphalt saturated felt Applied on earth-contacting side of walls Water pressure will force the membrane against waterproofed surface. Protected from puncture by a coat of cement plaster, fiberboard or wythe of masonry
Core borings
Most costly Reliable Made with a diamond drill that is hard enough to cut through rock.
Environmental risks (low)
Oil spills Groundwater pollution Radionuclides acid runoff to surface water Thermal pollution
NX durability grade
Only used for interiors, no wet or freezing environments
Retaining wall failture
Overturning sliding Undermining
Sources of lead
Paint Ceramics Pipes/plumbing Soil Drinking water Windows and window sills Doors and door frames
Sand
Particles from .05 mm to 2 mm in diameter Finest grains just visible to the eye Excellent for construction loads, drainage and sewage drain fields Unsuitable for landscaping
Silt
Particles from .05mm to 2mm in diameter Grains are invisible but can be felt as smooth Stable when dry or damp but unstable when wet Swells and heaves when frozen Compresses under load Building foundations and road bases must extend below it or must be elastic enough to avoid damage
Critical element in designing plazas and patios
Pavers
Levels of watertightness
Permeable Pervious Water-resistant Water-repellent Waterproof
Pervious (watertightness)
Permitting leakage or flow of water through cracks, leaks or other openings
Surface drainage system options
Pervious paving Sheet flow Gutters built into roadways and parking areas Ground swales
Phytodegredation
Phytotransformation. Breakdown of contaminants taken up by plants through the metabolic processes within the plant or the breakdown of contaminants surrounding the plant through the effect of enzymes produced by the plants
Grade beam characteristics
Piles are driven or drilled and connected with a continuous beam Used with expansive soils or clays are encountered near the surface
Surcharge foundation
Placement of mass of fill over the building limits to preload underlying soil and induce settlement prior to construction. Typical amount of surcharge is 1.5 to 2.0 times the weight of building to be constructed
Common causes of erosion and sediment and control fails
Poor site analysis Incompatible site and design Inadequately designed facilities Wrong materials Poor install Poor maintenance Seasonal differences
Exposure to PCBs
Poorly maintained hazardous waste sites Illegal dumping Leaks from electrical transformers Burning waste Accumulates in leaves and above-ground parts of plants, food crops and fish.
3 Positions waterproofing can be applied in
Positive Negative Blind
Environmental strategies for using concrete
Precast forms Recycle asphalt paving
Head
Pressure caused by weight of water
Vapor barriers
Prevent passage of water vapor
Waterproofing
Prevents penetration of water under hydrostatic pressure
Underpinning
Process of rebuilding or strengthening the foundation of an existing building or extending it when a new excavation in adjoining property is deeper than the existing foundation.
What should architect confirm in geotechnical report
Project/location Reference elevation of boring Water table elevation Understand relation between blow counts, boring depth, footings and soil. Soil beneath footing affects foundation performance.
How soil class definition is determined
Properties of top 100' of soil needs to be determined
Two steps in site analysis
Proposal phase to facilitate winning the work Post contract phase
Small Business Revitalization Act
Protects against CERCLA.
Landslide mitigation options
Provide setbacks Drainage (minimize water) Redundant (utility infrastructure)
Excavation bracing
Provides support against soil and water pressure as excavation deepens.
Design strategies directed towards minimizing the amount of impervious surface and maintain predeveloped rate of infiltration (parking)
Reduce parking space size Require smaller spaces dedicated to compact cars Design spillover parking with pervious paving
Moisture, soil and building problems
Reduction in a soil's loss bearing capacity Leakage of water into building Disintegration of certain building materials
Landscape restoration options
Rehabilitation Reclamation Remediation
Preferred method of storm water quality management
Reintroduce runoff into soil quickly to allow for recharge
Relationship between relative humidity and temperature
Relative humidity declines as temperatures increase
PCB removal
Remediation of waste, soil, gravel, concrete, buildings
Treatment of unsuitable soil on site
Remove and replace with compacted fill
Filter strips (characteristics)
Remove particulates (metals, phospherous, etc) by filtration through surface of the vegetation Promotes infiltration, slows runoff Minimum slope: 2% Usually grass Minimum 15' wwide Perpendicular to sheet runoff
Soil vapor extraction (brownfield)
Removes VOCs from soil through the use vapor extraction wells. Sometimes used in conjunction with air injection systems. Contaminants are volatilized and flushed in the air for treatment
Benefits of storm water infiltration
Removes particulates and pollutants that attach to soil particles Significant reduction in loss of recharge water
Sand filters (characteristics)
Removes suspended solids No biological treatment capability Minimum 1.5' deep Should be used in conjunction with other media or systems Used in conjunction with peat
Solidification (brownfield)
Removes water and changes the soil or solid media chemically to reduce permeability and transport of contaminants by percolation
Elevation change supports
Retaining walls Earth reinforcing Gabions
Methods of increasing slope resistance
Retaining walls Thermal treatment
Retention basin (characteristics)
Retains water in a pool Only outlet is emergency spillway Depth is usually 6" - 24" deep
Channelized flow erosion
Rill and gully erosion
Relationship between plant/tree-life and stream quality
Roots of trees, sedges and shrubs-- bind soils of banks to increase stability of stream banks and resist erosion Overhanging vegetation shades stream (cooler H20) Biotic debris decays and provides nutrients Biota contributes to the health of riparian and upland soils
Strategies to reduce storm water runoff in arid areas
Sand filters Filter strips Bioretention Minimize ground water pollution
Good aquifer materials
Sand, gravel, sandstone
Deconstruction
Saves useful materials for reuse in new construction and rehab projects
Requirements for foundations
Secure against structural failure Minimal settlement Technically and economically feasible
Bioretention basin
Shallow areas designed to collect storm water Drain fairly quickly Allows typical landscape plants to be used
4 basic types of applied waterproofing
Sheet membrane Fluid applied Cementitious Bentonite systems
Maximum desirable slope of walks adjacent to buildings
Should not exceed 4%
Dessication
Shrinking of soil due to capillary action. Leaves to overconsolidation.
Counterfort Retaining Walls
Similar to cantilevered wall but with counterforts placed at distances equal to or larger than one half height. Counterforts are used for walls greater than 25'
Solvent extraction (brownfield)
Similar to soil washing but solvents are used to remove contaminant from soils or solid media
Test pit (characteristics)
Simple excavation that permit direct visual inspection of the actual soil conditions. Allows close-up examination of the soil layers. Not dug below water table Costly
Gravity retaining wall
Simple, lots of material and variety of types. Low walls to 8-10'
Site analysis checklist
Site condition Zoning regulations Landscape ordinance Land development regulations Utilities access Traffic Topography Soils/geology Hydrology Vegetation/wildlife Historic or cultural features Existing parks/public areas Environmental concerns
Relationship between site work and storm water runoff
Site work results in an increase of storm water runoff
How number of tests to determine bearing capacity of soil is determined
Size and nature of building Size of site Type of soil Minimum of 3 or 4 observations (typically at corners)
Drainage in parking areas
Slopes should be between 1.5 and 5% Water should drain toward the edges of the parking area
Dry wells (characteristics)
Small excavated pits backfilled with aggregrate Collect runoff from small areas such as a roof Visible/near structure. appearance is important Soil filter can be used to make it disappear Can be incorporated into catch basic
Silty soil
Smaller particles with occasional plastic behavior
How to recognize expansive soils, wet
Soil is stick and will accumulate on shoes (2-4") Molded into a ball by hand and will leave a powdery residue on hands when dry Knife or shovel will penetrate easily Cut surface = smooth and shiny Heavy construction equipment will develop a thick coating
Determinants of feasibility of infiltration
Soil texture (adequate percolation) Ponding or dewatering must be a minimum of 3 days but no more than 7 days Minimum of 2' - 4' is available between water table/bedrock Nature of site (slope) and nature of soil will permit locations of foundations, utilities, etc
Underconsolidated soil
Soil that is built up in river delta, or similar, and are deposited in a very loose state. Souls tend to consolidate over time.
Soil strength
Soil's ability to resist deformation. Function of friction and cohesion of grain - grain contact in soil
Colluvial soils
Soils transported by gravity (landslides)
Most common types of shoring supports
Soldier beams and lagging Sheet piling
Gabions
Steel mesh cages filled with small rocks, absorb wave energy.
3 Stream zones
Stream zone Middle zone Out of transition zone
Phytoextraction
Subprocess of phytoremediation in which plants remove dangerous elements or compounds from soil or water (usually heavy metals)
Underground drainage conduits
Sufficiently sloped to be self-cleaning Minimum of .3% Placed at an adequate depth below the ground surface to avoid damage by vehicles and to prevent freezing
Sheet erosion
Surface and runoff flows in a sheet
Two types of site stabilization
Temporary Permanent
Types of soil exploration tests
Test pits Soil load tests Borings
Variables in effective planting design synthesis
Textures Color Line Form Balance
Hydrostatic pressure
The pressure of water against the walls of its container.
Green roof installation on metal deck
Thermal barrier Rigid insulation Waterproof membrane Root barrier Drainage layer Growth medium
How planted parking lot islands impact stormwater runoff
They can intercept stormwater Shade and cool parking lots (reduced maintenance costs)
Deep excavation for a high rise building in an urban area requires
Tiebacks
Sheet piling
Timber, steel or precast concrete planks driven vertically side by side to retain earth and prevent water from seeping into an excavation
When is underpinning utilized
To deepen foundation based on new work To provide additional foundation capacity to an inadequately supported structure to provide new loads to existing structures
Void ratio (soil)
To determine compressiblity/compaction Loose soils high void ratio
Grain shape (soil)
To estimate shear strength
Liquid and plastic limits (soil)
To obtain compressibility and compaction values
Bored (drilled) pile
Transmits load to soil by skin friction. Vertical shaft drilled into the ground and filled with concrete.
Constructed wetlands
Treatment system for on-site sewage disposal systems that have physical limitations Requires a septic stank Limited capacity to treat solids
Location of trees : building
Trees should be planted 1/4 to 1/3 of their mature height away from the building
Ditches (dewatering)
Trench dug beneath water table. Water is directed to low point and pumped out. Typically at perimeter of job site.
Aquifer
Underground permeable material through which water flows
Phytoremediation (brownfield)
Use of selected plans to remove or biostabilize contaminants in soil, sediments or water
Stormwater management
Use of structural or nonstructural practices designed to reduced stormwater runoff pollutant loads, discharge volumes and peak flow discharge rates
Gravity Retaining Walls (characteristics)
Used for low retaining walls Resist forces on it by its own weight and by soil pressure and soil friction against its surface opposite to earth forces
Retaining wall batter
Used on taller retaining walls, wall tilts in to give impression that wall will not topple over
Type S Mortar
Used when freezing is expected
Type M mortar
Used when freezing is not expected
When to use a wash boring (soil exploration)
Used when soil is too compact to use an auger Useful in locating bedrock Uses a 2" - 4" diameter pipe that is driven into the soil and contains a smaller jet pipe through which water is forced.
Dry sample borings
Utilize a drive pipe with a special split sampling pipe at the tip.
Soil Mixing
Utilized to remediate soil contaminated with a chemical by blending it with a chemical that renders it harmless
Phase I Environmental Assessment
Utilized when site was previously used for industrial or commercial activities or if owner requires a higher standards of care. Cost effective No collective or testing of samples Cannot definitively determine contamination, only that there might be
Floating/compensated foundation
Utilized when soft soils are susceptible to settlement and dense soils are too far down to reach with deep foundations similar to mat foundation but is placed beneath building.
Tiebacks (excavation bracing)
Utilized when subsoil conditiosn permit.
N-year storm
Value of n is based on the probability that a storm of this magnitude or greater will occur at this location in any given year.
Stream buffer
Vegetated area near a stream, usually forested that helps shade and partially protect stream from impact of adjacent land uses. Plays key role in water quality.
Green roofs (characteristics)
Vegetated roof covers Reduce runoff in a temperate climate by 50% Absorb carbon dioxide Reduce ambient air temps Filters the air Reduces heat island effect Protect roof membranes from UV light degradation, temp extremes, wind/hail Adds acoustical insulation Adds aesthetic appearl to roof
Temporary methods of site stabilization
Vegetation Geotextiles Stone
How to lower radon levels
Venting from beneath house. Seal foundation and cracks.
Dynamic head
Vertical distance pump must life the water
Environmental issues with PVC
Vinyl chloride is a carcinogen (results in presence of dioxin) Burning of PVC = dioxin in environment
Soil washing (brownfield)
Water is used to flush through soils or medium to flush contaminants out. May involve removing solids and using mechanical agitation Additives may be used to increase the efficiency of the process
Drawback of storm water infiltration
Water soluable pollutants such as nutrients, pesticides or salts dissolve in water
Sheet flow drainage
Water that drains across a sloping surface whether the surface is paved, grassy or otherwise landscaped
Green roof installation on concrete deck
Waterproof membrane Root barrier Drainage layer Filter fabric Growth medium
Rainwater cistern properties
Watertight: prevent contamination Opaque: prevent algae growth
Dewatering Methods
Well points, deep wells, ditching/sump pumps
Areas not suitable for site development
Wetlands Above a 100'-year flood plain Habitats for endangered species Historic sites Prime farmland
Dew point
When relative humidity is 100%
Sanitary sewer trench depth (key factors)
Worker safety Cost of installation and maintenance Loading on pipes Wider trenches = less support
Underground water zones
Zone of aeration Ground water table Zone of saturation
Ground slope surfaces
a. minimum slope for surface drainage b. proper slope away from building edge c. proper slope for range of drainage ditches d. maximum slope for a grassed area e. maximum slope for stable soil and surface is protected (ivy, rocks, etc)
Rakers (excavation bracing)
angled supports that transmit forces into the ground
Treated lumber finishes
creosote (oil) pentachlorophenol (oil) copper napthenaic (oil) chromated copper (water) ammoniacal copper quaternay compound
ASTM 4 step process for conducting life cycle assessment
define goals analysis of inventory impact assessment interpretation of findings
Rainwater availability calculation
(Catchment area)(Average rainfall)(factor)
Dioxin
one of the most toxic human-made chemicals. Stable, long-lived, by-product of herbicide production enters environment as fallout from the incineration of municipal and medical waste and persists for many years.
Most sustainable type of development
redevelopment
Dewatering
removal of water from an excavation before and during excavation
PCBs
synthetic chemicals containing chlorine that are used in the manufacture of plastics and other industrial products, become stored in the tissue of animals, and also persist in the environment
Frost action
the alternate freezing and thawing of soil and rock
Dewatering excavation site methods
well points slurry walls soil mixed walls (watertight barriers) soil freezing
Surface water is directed to
yard drains catch basins underground storm drain lines
Minimum slope required for drainage at building
2%
Drainage ditch slope
2% - 10%
Distance between bottom of infiltration facility and water table/bedrock
2' - 4'
Typical height of cantilevered retaining wall
20 - 25'
Spacing of soil test pits/test borings
25 - 150' for multistory buildings 50 - 200' for single story buildings
Maximum desirable slope of grassy recreation areas
3%
Typical spread footing dimensions
3' x 3' minimum 20' x 20' maximum
Percentage of US electricity is generated by burning coal
50%
Reasonable time frame to drain an infiltration structure
72 hours
Problematic radon level
< 4 pci
Rough grading
Addition or removal of earth prior to the start of construction
Earth reinforcing
Alternative to conventional retaining wall, where soil is compacted in layers,each sandwiched between meshes of steel
Drivers in design of drainage system
Amount of runoff Intensity and duration of storms Size of area drained Characteristics of drained area (soil porosity, slope and vegetation cover) The amount of streets, paving, parking areas, roofs
Passive treatment wells (brownfield)
Barriers are construction of reactive materials and installed in an aquifer to promote a chemical reaction between the barrier and the contaminant in the groundwater. ie limestone barrier used to increase the pH of groundwater
Bed material components
Base layer, setting layer (leveling course)
Geotechnical information needed for soil to balance site
Bearing capacity Bulking factor Depth and character of bedrock
Plate load test
Bearing capacity of soil static loads on spread footings
Health issues caused by PCBs
Cancer Compromised immune system Reproductive issues Endocrinological issues
Dechlorination (brownfield)
Chemical treatment to remove chlorine atoms bonded to hazardous chemicals. Hydrogen or hydroxide ions are used to detoxify materials
Reclamation (landscape restoration)
Construct new landscape
Types of underpinning
Continuous Intermittent
Types of excavation bracing
Crosslot bracing Rakers Tie backs
Building foundation must support these loads
Dead load Live load Rain and snow loads Wind loads Seismic loads Soil and hydrostatic pressure Buoyant uplift load Flood loads
Plasticity index (soil)
Difference between liquid limit and plastic limit.
Brownfield Redevelopment cleanup standards
Do nothing Use administrative/institutional controls Engineering controls On-site remedial action Off site disposal/treatment (most expensive)
Deep foundation types
Driven piles Bored piles Caissons
Benefits of balloon framing in cold climates
Eliminates thermal bridge.
Principal reason for soil testing
Establish intrinsic characteristics of soil
Floating foundation installation
Excavate soil equal to weight of building Install mat or raft foundation. One foot of soil removed is equal to one story of the building to be constructed.
Peat (and other organic materials)
Excellent for landscaping Unsuitable for building foundation and road bases
Plasticity index of less than 15
Expansive soil
Retaining wall and depth in soil
Extend 2' below or 1/2 the above grade height to frost line (whichever is greater)
Consequences of expansive soils
Extensive cracking of sidewalks, foundation failures, retaining wall failures
SX durability grade
Exterior grade; utilized where freezing will occur
Source of dioxins
Fatty tissue of animals Food
Permanent methods of site stabilization
Finished surface Vegetation Paving Geotextiles Stone
Storm water
Flow of water on ground surfaces or drainage channels produced by rainfall or melting snow
Relationship between foundations and frost line
Footings and foundations must be placed below the frost line to prevent the structure from lifting up
Location of footing
Footings should rest on undisturbed native soil and extend beneath frost depth.
Building's foundation in relation to water table
Foundation should be located well above the site's water table
Nonvegetative stream bank stabilization
Gabions Deflectors
Soil grain classification
Gravel Sand Silt Clay
Higher soil bulk density
Greater support it can provide for foundation
Retaining walls
Hold soil back to allow for an abrupt change in elevation.
How are pool pumps specified
Horsepower and head
Landscaping improvements on energy efficiency
Improve energy efficiency by 30% Provides shade for buildings Evaporative cooling, transpiration and latent heat of evaporation May reduce reflected light from buildings Sunscreens
Water-repellent
Incapable of transmitting water by capillary action but able to transmit water under pressure
Problems caused by improper runoff control
Increased load on local sewers Increased potential flooding Pollution of waterways with sediment road salt, etc Erosion of sites and waterways Erosion of stream banks Accelerated soil creep or landslides Stream warming Loss of acoustic biodiversity
Air sparging (brownfield)
Injection of air into groundwater to flush volatile contaminants which are collected and treated by the soil vapor extraction processes
Blind side waterproofing installation
Installed before the element is built
Positive side waterproofing installation
Installed on side exposed to water Most common
Capped site development
Isolates and contains contaminated material from receptors and from and from natural transport mechanisms. Trenches can be lined with cap material
Treating soil in permanently cold environments
Keep soil frozen in order to maintain strength. Self contained convection Mechanical refrigeration.
Methods of sewage treatment
Large scale treatment plant Constructed wetlands
Vitrified Clay Pipe Characteristics
Largely replaced by PVC Durable Resistant to chemical corrosion Lowest thermal expansion Heavy = more handling; greater labor costs for install
Water pollution non point sources
Less easily to identify source
Portion of home at risk for radon exposure
Levels beneath the 3rd floor.
Cohesionless soil
Little to no friction when loose. Must be confined to support loads Granular soils Gravels Sands Silt Little to no clay content
When to use bored pile over driven pile
Loads are exceptionally high and bearing surface reliable Work is in close proximity to existing structures where vibration from driven piles may damage existing structures Inspecting bearing surface is important and limited inspection of the bearing material is possible.
Benefits of meadows (versus lawns)
Low maintenance Mowed only once a year, in the fall
Treatment of formaldehyde
Lower humidity level Increase ventilation
Characteristics of HDPE pipe
Lowest cost Lightest and most flexible of pipe materials Easy to manufacture Easily recyclable Greatest expansion coefficient (< PVC)
Health issues caused by asbestos
Lung disease Mesothelioma Asbestosis
Pervious paving
Material that can withstand vehicular or pedestrian traffic, but allows water to pass through and seep into the ground below.
Unmowed ground cover slope parameters (drainage)
May be as steep as 50%
Soil shear strength
Measure of frictional resistance and cohesion of a soil.
Type II Abrasion resistance grade
Medium resistance Restaurant entrances
Types of waterproofing
Membrane waterproofing Waterstops
Remediation (landscape restoration)
Mitigating a condition that caused destruction
Tilt
Mixture of clay, silt, sand, gravel and boulders deposited by glaciers
Slurry wall
More expensive form of excavation support that is economical if it becomes part of the permanent foundation of the building. Constructed by excavating a trench in short lengths, filling it with a slurry of bentonite and water to prevent the sides from collapsing
Shallow foundations
Most economical Employed when stable soil of adequate bearing capacity occurs relatively near to the ground surface.
When to use auger borings (soil exploration)
Most effective in sand, clay or depths not exceeding 50' Auger stops at the first obstruction
Type I Abrasion resistance grade
Most resistance Driveways
Durability grades for pavers
NX MX SX
Water content (in cohesive soils)
Obtain compressiblity and compaction values
Mat footing characteristics
One large footing beneath the entire building Raft foundation
What should occur before a land title is transferred
Phase 1 environmental assessment and a transaction screen
Liquid limit of soil
Point at which soil liquifies (plastic to liquid state)
Splash erosion
Raindrops on unprotected soil
Sources for potable water
Recycling water (limited) Desalinization (energy insensitive) Expanding use of existing sources Conservation (affordable)
Methods of reducing storm water runoff
Reduce impervious paving Reduce roofs Infiltration Detention and retention ponds Green roofs
Cantilevered retaining wall
Resists forces by the weight of the structure as well as by the weight of the soil on the heel of the base slab.
Rehabilitation (landscape restoration)
Restore environmental function
Negative characteristics of lawns in sustainable design
Results in use of pesticides, fertilizers, mowing
Dewatering alternates
Sheet piles/slurry walls Freezing gorund
Two main sources of radon
Soil water
How to recognize expansive soils, dry
Soil is hard, resists penetration by knife Cut from shovel leaves a shiny surface Surface may display cracks in a regular patten Width and spacing of cracks indicate the relative expansion potential of the soil when wetted Surface irregularities (footprints, tire tracks) cannot be obliterated by foot pressure
Bedrock
Solid material that forms the crust of the earth Generally the strongest support for the foundation of a structure
Brownfield cleanup options
Solidification Soil vapor extraction Incineration Bioremediation Soil washing Solvent extraction Dechlorination Phytoremediation Air sparging Passive treatment wells
Water pollution point sources
Source and owner can be identified
Key soil properties to test for
Specific gravity Grain side Grain shape Liquid and plastic limits Water content Void ratio Unconfined compression
Shallow foundation types
Spread footings Basement Crawlspace
Column Footing
Spread the load from the structure and the foundation over a large area so the load capacity of the soil is not exceeded and settlement is minimized Act like inverted beams (compression and tension)
Types of pond pumps
Submersible and larger centrifugal pumps
Geotechnical report
Summarizes info gained in soil exploration field tests Recommends foundation types and depths, bearing stresses
Crosslot (excavation bracing)
Temporary steel wide flange columns that are driven into the earth.
Cohesive soils
Tend to stick together, exhibit cohesion when submerged. ATTRACT WATER EXPANSIVE Fine grained soils Any soil with a significant amount of clay
Bored pile materials
Timber, steel, concrete, composite
Consolidated tilt
Well graded, strong and excellent for foundations
Issue with wash borings
Boulders may be mistaken for bedrock
Ideal driven pile installation
Cohesionless soils with few boulders When groundwater or methane gas is present above the suitable bearing soil layer
Ideal bored pile installation
Cohesive soils Obstructions that can be tolerated right away Dense reliable bearing surface
Wall footing
Continuous spread footing that serves the same purpose under a wall as a column footing
Dampproofing preventative measures
Draining surface water away from foundation Granular fill under a concrete slab (deters capillary action) Polyethlyene film vapor seal over granular fill Footing drains
Deep foundations
Employed when the soil underlying a foundation is unstable or of inadequate bearing capacity. They extend down through unstable soil to transfer building loads to a more appropriate bearing stratum of rock or dense sands and gravels below the superstructure Scour from water table can occur at surface Structure transmits tension loads to foundation Large horizontal loads transmitted to foundation Reducing settlement or differential settlement is crucial
Relationship between porosity and permeability
Greater porosity = low permeability
Methods of surface water from structures
Gutters Flumes Berms Warping of paved surfaces
Ground surface slope categorization
Level Easy Steep
Blow counts
N value. Number of blows required to drive device last 12" of standard penetration test.
Loam
Organic materials: humus, sand, silt, clay Excellent for agriculture Will settle a great deail over time.
Steep grade ground surface
Over 10% Most difficult to use More expensive for building construction because of complicated foundations and utility connections
5 basic types of spread footings
Single column Wall footing Combined footing Cantilever footing Mat/raft footing
Slabs on grade and moisture prevention
Slabs placed over a gravel several inches thick to prevent water from being drawn into slab via capillary action.
Easy grade ground surface
Slope between 4 and 10% Suitable for most construction and activity
Level grade ground surface
Slopes under 4% Suitable for construction and outdoor activities
Grain size (soil)
To estimate permeability, frost action, compaction and shear strength
Unconfined compression (in cohesive soils)
To estimate shear strength
Piles
Type of deep foundation Utilized if upper soils have insufficient bearing capacity to support spread footings Enables the building load to be transmitted to deeper, firmer soils Can be drilled or driven.
Finish grading
final distribution of earth at the conclusion of construction
Combined footing
Used to support 2 or more columns
Foundation walls
Utilized when basements are not required Need to support a limited load on firm soil exists. Typically 8" thick.
Cantilever footing
Utilized when footings are located tight to properly line. Eccentrically loaded.Exterior column footing joined by a concrete beam to an interior footing
Drilled caisson
Vertical shaft drilled into the ground and filled with concrete Bottom of the shaft is enlarged or belled to for a larger bearing area
Best drainage soil
Well graded coarse-grained (uniform sizes); uniform size = larger void volume
When to use boring tests
When information is required beyond the depth of a standard test pit/beyond depth of water table.
Residuum
soil derived from in place decomposition of bedrock materials (more weathered near surface; more rock-like with greater depth)