Transcript Document
Site Work 1 Major Topics Site Plans/Surveys Grading Compacting/Erosion Earthwork Soil Surface & Groundwater Paving and Surfacing Materials 2 Site Plans Include: All information shown on a survey Changes in topography or grade Demolition of existing construction Exact location of new construction 3 Surveys Legal description of a piece of land Typically done by a registered land surveyor Surveys include the boundaries and elevations of land plots and buildings (in text and drawings) 4 Topography or Grade Contour lines show elevation Closer the contour lines are together- the steeper the slope This information is critical in determining how much earth must be moved to prepare site for structure being built 5 Grading Both the rough and final grades on a building site are established by grading, using power equipment and hand tools. Grading is needed wherever slabs, pavement, walks, and landscaping is anticipated. Finish grading should slope downward away from the building at a minimum of 6 inches/ 10 feet (about 5 %). 6 Compacting Compacting applies energy to soil to consolidate it by compressing air voids to increase the soils dry density. Minimizes settling Increases load-bearing capabilities Increases soil stability Reduces water penetration 7 Slope Protection & Erosion Control Building codes often dictate prevention of erosion Possible methods used include: Filter fabrics – open weaved mats of nylon or other synthetic materials Riprap – a layer of stone or broken concrete used to control or divert the flow of water 8 Earthwork Involves some type of cutting (excavation) or filling of soil materials The level down to which the materials are removed is determined by the contract documents This phase of site work is referred to as “rough grading” Soil testing is usually performed at this time 9 Fill and Backfill Soils used for fill should contain no vegetation or foreign materials that would cause uneven settlement. Beneath slabs a base course (4 “ thick mixture of gravel, crushed stone, sand, or crushed slag) should be provided. See figure 21.3-12 on page 1079 for acceptable soils to use for fill 10 Soil Testing Identify the materials on the site Determine Soil density Moisture Content Load-bearing capacity Shear Strength Plasticity index Analyze the gain size of soil particles 11 Soil Types Division Description Value as a foundation material Gravel and Gravelly Soils Well-graded; Gravel-sand mixtures; little or no fines Excellent to good Sand and Sandy Soils Silty sands, sand-silt mixtures Fair Silts and Clays Organic siltclay of low plasticity Poor to very poor 12 Primary Soil Considerations: DewateringCritical in sub-surface foundations (basement –earth sheltered) Open-drain (French) & gravel used to lead water away Pumps may also be used to remove excess water Compaction – critical !! - to prevent uneven load settlement 13 Soil Considerations con’t: Stabilization – use various additives to adjust the properties of soil Poisoning- used to control termites * Note: certain chemicals are no longer used due to environmental concerns 14 Termite Control Subterranean termites pose a great hazard to building materials – especially in mild climates Termites live underground but build tubes of earth to reach wood, fiberboard, fabrics, and paper. They must have a constant source of water or they will die They enter a structure by attacking wood in contact with the ground, through small cracks, or by flying. 15 Soil Poisoning Because of environmental concerns many chemicals are no longer used for this Acceptable termiticides include: Chlorpyrifos Cypermethrin Fenvalerate Isofenphos Permethrin 16 Surface & Groundwater Surface water – most problems with this arise from improper grading Slabs on grade – problems may be eliminated by proper grading, selecting correct base materials, and installation of a vapor retarder Vapor Retarder – this membrane should resist deterioration, be thick enough to resist penetration (usually 6 mils), and be overlapped 6 inches during installation Common material used is polyethelene sheeting 17 Paving & Surfacing Different materials are used to perform each Paving – uses concrete, stone, or brick Surfacing – uses flexible and waterbound surfaces 18 Asphalt Is a dark-brown to black, solid or semisolid, mainly composed of Bitumens (a tarry mixture of hydrocarbons) Bitumens also used in: Water proofing coatings Sheet Water proofing Damp proofing below grade Asphalt moves into a liquid state when heated Coal Tar Pitch – greater water resistance than asphalt, good adhesive properties, unlike asphalt - contains very little bitumen 19 References Construction Materials and Processes, 3rd Edition. Watson, Don A.. McGraw-Hill, 1986. Imprint 2000. ISBN: 0-07-068476-6 Construction Principles, Materials, and Methods, Seventh Edition. H. Leslie Simmons, John Wiley and Sons, Inc., 2001. Olin’s Construction Principles, Materials, and Methods, Eighth Edition. H. Leslie Simmons, John Wiley and Sons, Inc., 2007. Architectural Materials for Construction, Rosen, Harold J. and Heineman, Tom. McGraw-Hill, 1996. ISBN: 0-07-053741-0 Basic Construction Materials, 6th Edition. Marotta, Theodore W. Prentice Hall, 2002. ISBN: 0-13-089625-X Building Construction: Materials and Types of Construction, 6th Edition, Ellison, Donald C., Huntington, W.C., Mickadeit, Robert E.. John Wiley & Sons. ISBN: 0-13-090952-1. Architectural Graphic Standards: Student Edition, Abridgment of 9th Edition. The American Institute of Architects. John Wiley & Sons. ISBN: 0-471-34817-1 20