Term
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Definition
separation reinforcement filtration surface protection |
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Term
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Definition
| a crack in pavement because the pavement it is on also cracked there. |
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Term
Woven vs non-woven geotextiles
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Definition
woven: threads wound together become yarn, yarns woven form warp and weft. Fabric is weakest and least flexible in direction of yarns. # of yarns=thread count. Can also have finish. non-woven: mechanical entanglement, chemical bonding or thermal bonding. long threads or short. often needle punched to increase permiability. evenly strong and stretchy in all directions. |
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Term
most important properties for geotextiles in landscape applications
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Definition
thickness and porosity. then roughness
thicker=stronger but get clogged. Porosity units:EOS(Equivalent opening size), corresponds to sieve size. rougher=slows down water more, grips earth as a deadman better. |
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Term
three mechanical properties of geotextile fabric
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Definition
elongation: %+ length when fully extended Grab Strength: LBs required to pull it apart. Burst pressure: pressure req to burst a section |
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Term
factors in geotextile selection
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Definition
filtering(clogging) permeability k pore size(EOS) moisture absorption(esp. with natural fibers) chemical resistance(fertlzr,org.soil,+PHsoil,oil,asph) UV resistance tensile strength and extensibility(uneven, steep) thickness different soils on each side connection details(seams, |
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Term
geotextile applications-separation
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Definition
roadway and railway beds(between subgrade and subbase) Earth dam(many different materials to separate planters (drainage medium from growing medium) formwork (mat or tube forms, like an air matress. Good for inaccessibile places, or "sandbags") |
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Term
| Applications for geotextiles-reinforcement |
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Definition
-paving(prevent reflection cracks w/ a tack coat) -retaining walls(tie-backs anchor facing unitsusing weight of ground behind the wall to hold facing units -Slopes(steeper than angle of repose. used w/ plants: horizontal pieces every 2 feet, soil compacted. -Roadways(compressible fabrics reduce amnt of aggregate base. maintain proper drainage, separate materials. increases load bearing. -turf( 3-D geotextiles. distribute weight to subgrade, don't compact grass. Can also just mix long fibers into soil. |
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Term
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Definition
California Bearing Ratio ability of soil to resist a load. |
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Term
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Definition
| weight on pavement squishing subgrade down into soil and vica versa |
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Term
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Definition
-minimum fabric permeability to not inhibit soil drainage: more than .1 K of the soil(the permeabiity of the soil itself) Ideal fabric permeability: greater than or equal to K, unless soil held by electrochemical forces(then up to 5XK) -piping prevention for soils under 50% silt: EOS fabric is less than 2X the sieve size that lets through 85% of the soil. For soils over 50% silt: EOS fabric is less than 1X sieve size that allows 85% To prevent clogging, EOS min= 100 or open area of 4%. according to engeneers. |
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Term
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Definition
soil squeezing through geotextile. Prevented by buildup of "filter cake" of fine particles that build up next to filterfabrics.
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Term
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Definition
trapazoidal channel with flat bottom sized to convey a 2 year storm volume below erosion speeds(4-5 ft/sec) and total volume to accomodate ten year rainfall w/o erosion(7ft/sec) For water quality: max speed 1ft/sec, water must go at least 10'. bottom shouldn't be mroe than 6' wide to prevent braiding.
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Term
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Definition
Planned Unit Development. both a type of building development as well as a regulatory process. A PUD is a designed grouping of varied and compatible land uses, such as housing, recreation, commercial centers, and industrial parks, all within one contained development or subdivision. credited to Prince Georges County, Maryland in 1949. hierarchy of street types, openspace, commercial, industrial, variety of housing all mixed. |
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Term
infiltration well spacing
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Definition
2-4' above high water table. 3' above bedrock(to prevent pollution). 100' from wells. 10' from buildings. Bottom of infiltration bed below frost line. Soils' min infiltration rate must be more than .27"/hr |
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Term
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Definition
water quality volume. Qality treatements that accomodate this volume of water(1.25", generally) will catch most pollution in a given year. Can be calculated w/ Schueler's short cut method(Vilumetric runoff coefficient(Rv)=.05+.009*I(%watershed imperviousness). WQV=design rainfall amnt(P)*Rv) or small stomr hydrology WQV method(same formula with values from a table, runoff coefficient). swales, etc designed to aacomodate this amnt. |
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Term
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Definition
vertical:30 degrees horizontal: 60 degrees |
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Term
Stairway dimensions Widths tread-riser ratios height between landings |
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Definition
min width for public: 42" ratio constant for any stairway. 2*Riser+Tread=26-27". 4.5<R<6 no single steps. at least 2, pref. 3, marked w. handrail, lights, stripes, etc. Pitch tread 2% downward for drainage. space between landings: 10vert.'. 5' pref! |
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Term
| performance specification |
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Definition
| specifies no method, just requirements for the final prduct's performance. It is up to the contractor to pick a method that will fulfill the requirements. As opposed to Prescriptive specification. |
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Term
prescriptive specification
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Definition
a spec with specific instructions and methods for the contractor, not just requirements for the final product.
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Term
ramps: min width max slope curb cuts max slope distance btw landings |
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Definition
min width-3' for one-way, 5'for 2-way, more for wheelchairs max slope: 1:12 (8.44%)
curb cuts max slope-1:8(12%) distance btw landings-30' |
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Term
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Definition
metal brace for corners-open book-shaped
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Term
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Definition
| Granular material that passes through a 3/8" sieve. |
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Term
Soil compaction: sandy clayey mix |
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Definition
Ramming Machine- clay vibrating roller-mix static roller-sand |
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Term
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Definition
| The ability of the soil to serve as a constructed subgrade,Ratio) 100 psi = best, 50psi or better adequate for compacted base. CBR is expressed as a percentage compared to the test against crushed stone base. The higher the CBR the higher the "bearing" capacity of the soil. |
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Term
| frequency of expansion joints and control joints |
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Definition
expansion-every 500 sqft control- every 100 sqft
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Term
max height of a wall before an engineer has to sign off on it
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Definition
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Term
weight of a cubic ft of concrete
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Definition
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Term
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Definition
5' clear zones all around, 20'X44' (doubles)
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Term
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Definition
high school: 84X50' college: 94x50' + border brings it to 114X70 international: 18mx30m |
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Term
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Definition
one wall: 34'X20'X16'(tall) three or four walls: 40x20x20' |
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Term
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Definition
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Term
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Definition
Use area: 60x120' +10-12' between courts actual court: 37x78 |
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Term
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Definition
30x60 +12-20 on each side
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Term
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Definition
jr. high: 165'x300' high school: 195'x330' championship: 225' 360' |
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Term
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Definition
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Term
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Definition
min 172x372(including sidelines)
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Term
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Definition
| Adsorption, the binding of molecules or particles to a surface, must be distinguished from absorption, the filling of pores in a solid. The binding to the surface is usually weak and reversible. |
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Term
atmospheric vacuum breaker valve AVB |
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Definition
| An Atmospheric Vacuum Breaker (AVB) is a backflow prevention device used in plumbing to prevent backflow of non-potable liquids into the drinking water system. It is usually constructed of brass and resembles a 90-degree elbow with a hood on its top to allow air to enter the water system if a siphon attempts to form. Inside this elbow is a poppet valve that is held "up" by the water pressure found in the system, closing the air entrance to the device. If the pressure in the "upstream side" is reduced to atmospheric pressure or below, the poppet valve drops and allows air to enter the system, breaking the siphon. |
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Term
additive vs deductive alternates
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Definition
| owners can request that bidders give a range of estimates, by having a range of scope.: The base bid, the basic scenario with additives depending on which options could be cut or added. For addative alternates, the base bid is the minimum, alternates are added features. Deductive alternates start with a full-feature base bid and subtract features. Additive may be better for the owner because of the kinds of things the contractor will neglect to count in alternates that they will count in base bids. http://www.jhdconstruction.com/AddVDed.html |
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Term
| Grid or borrow pit Method for estimating cut and fill |
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Definition
Draw a grid over the area that is changing grade. Label each intersection of that grid depending on how many other points they connect to, a only connects to two other corners, b connects to three etc, up to d which has a connection in every direction. Determine X: X=square footage in one square. add up the change in grade for all the a points. =A. Do this for each letter. Volume= ((A+2B+3C+4D) *X)/4 |
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Term
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Definition
| method for calculating volume of cut and fill for linear elements, generally. Regular cross sections are taken at 50' to 100' perpendicular to the center line. Average the areas and multiply by the distance between them. Get it into cubic yards, the common soil unit. |
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Term
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Definition
volume estimation for cut and fill. Take area of each space between an existing and corresponding proposed contour. Add up all the area and multiply by contour interval. Can get much more involved, finding topsoil stripped, excavation for areas wwhere pavement will go, etc.
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Term
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Definition
Rational method for calculating runoff. Q=peak discharge of runoff in cubic feet per second. K=Constant(=1) C-runoff coefficient(ration of runoff to rainfall) A=Watershed area in hectares. Assumes even rainfall, peak discharge at "time of concentration" and this is never less than 6 min. OK for small watersheds. |
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Term
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Definition
time it takes for water fallen on farthest part of watershed to reach water exit. At that point the volume of water leaving will cease to increase, assuming constant rainfall.
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Term
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Definition
Schueler's short cut method. good for sites with mostly one type of cover. Rv=volumetric runoff coeficcient=.05+.oo9I where I=%imperviousness P=design storm inches W=Water Quality Volume |
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Term
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Definition
Water Quality Volume The volume of water that will catch most rain water(from all the little storms). Used to calculate how much waer treatment methods should be able to handle. |
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Term
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Definition
R=hydraulic radius in feet
A=cross-sectional area in square feet P=wetted perimeter in feet A relationship between how much water is being conveyed and how much friction with the sides there will be. Used to evaluate efficiency of channel shapes at a given design depth of water. |
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Term
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Definition
Manning Formula. V=Velocity in feet/sec n =Manning's Coefficient of friction R=Hudraulic radius of flow in feet S=Longitudinal slope of hydraulic grade line(water surface) in ft/ft (paralel to channel bottom in steady conditions)
K=Constant(1.486) |
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