CONE 2200 Construction Methods Exam-1 Review PDF

CONE 2200 Construction Methods & Plans Reading Exam-1 Review Session 1  2 Design and construction process has four discrete phases Pre-design phase Setting objectives & crit...

CONE 2200 Construction Methods & Plans Reading Exam-1 Review Session 1  2 Design and construction process has four discrete phases Pre-design phase Setting objectives & criteria for planning Design phase Determining geometry, materials, and performance of structure Pre-construction phase Selection of project participants Outlining contractual agreements Construction phase Physical realization of a finished building 2  3 Design and construction process has four discrete phases Pre-design phase Starts after the owner identifies the design firm (consultants) Sometimes referred to as a feasibility study Owner & consultant determine the goals & objectives of project Identify needs and constraints Title search & zoning analysis, Site search & selection Financial planning Scheduling and programming 3  4 Pre-Construction Activities Securing building permit Dewatering Selecting project participants Shoring Sign contractual agreements Underpinning GC establishes a field office Earthwork Subsurface investigation, Installing utility infrastructure Site preparation for construction, Site improvements (access road, walks) 4  5 Pre-Construction Activities Arrange access for deliveries and equipment Designate space for storage and staging of materials Designate space for sorting and storage of construction waste materials Arrange a pre-construction conference (owner, GC, construction manager, and Subcontractors) 5 6 6  7 Main players in a construction team Owner: Initiates project Architect and engineers: design the building General contractor: completes actual construction Supporting the main construction team Consultants: provide professional services to the main team Subcontractors: perform portions of work under GC Product representative: assist with submittals, furnish field services (consulting, inspecting installations) Manufacturers: produce materials or products Testing labs & inspection agencies: provide quality control services 7  8 Orthographic drawings Floor plan: the image of a building looked down after a horizontal plane has been cut through it and the top portion removed. Footprint of a building Building section: view of a building after a vertical plane has been cut through it and the front portion removed. Elevation: view of the exterior façade of a building, delineating geometries and the materials of construction. Shop drawings Provides precise directives for the fabrication of certain components, such as structural steelwork, concrete reinforcing, or pre-cast concrete components. 8  9 Site assessment Performed before any construction begins Ensures an efficient design and construction Involves land and topographic surveys, subsurface soil testing, environmental studies 9  10 Site Plan A detailed drawing of the proposed site development project Prepared by a licensed architect, engineer, or surveyor. Illustrates locations, dimensions, and floor elevations of structures Site entrance & exits, drives, fire & service lanes, Parking & loading areas, pedestrian walkways Existing & proposed underground & overhead utilities, grades Locations of public or private site lighting and fire hydrants Existing contours & proposed elevation changes to help verify drainage 10  11 Site Work Activities The activities includes many activities such as: Erosion control, demolition, earthwork, and site remediation Foundations: spread footings, piles, caissons Wet environment: dredging, underwater work, & constructing seawalls, jetties, docks Utility trenches: water, sewer, gas, oil, steam distribution Constructing ponds, drainage reservoirs, sewage lagoons Walks, fences, irrigation systems, & landscaping 11  12 Site work should pay attention to: Conservation of natural features Escape of pollutants from the site Restoration of damaged areas Keeping earthwork and other site disturbances close to the perimeter of the built environment Protecting & restoring existing vegetation that remains at end of the project Properly stockpiling and protecting stripped topsoil for reuse Prohibit the discharge of toxic waste materials Acknowledge the existence of flood zones 12  13 Sedimentation and Erosion Control Storm water transports dirt & contaminants Temporary erosion and from construction site sedimentation control measures Temporary seeding Erosion & sedimentation problems should Mulch barriers be controlled Earth berms (raised bank) Civil engineer identifies areas prone to Silt fencing erosion & suggests strategies for soil Sediment traps stabilization Permanent plantings, fast-growing grasses Placement of earthen swales (depression) to divert runoff water into temporary sediment basins 13  14 Storm-Water Drainage Removal of water from a development area Very essential during and after construction Prevents water from entering basements or pooling on surfaces Drainage plan uses topographic map with contour elevations Surface drainage system: ditches, swales, detention basins Subsurface drainage: drainpipes (concrete, polyvinyl chloride (PVC)) leading to storm-water system or catchment area 14  15 Demolition Breakdown & removal of existing structures o buildings, roadways, parking areas, o submerged tanks, utility lines May include the removal of hazardous materials (asbestos) Site clearing:- removal of trees and other vegetations Grubbing:- removal of subsurface obstructions (roots, stumps, etc.) 15  16 Site Remediation Involves activities that benefit the building site in the long-term Generating productive soils Restoring natural habitats Removing toxic substances Preventing erosion 16  17 Earthwork Is related to soil excavation, transportation, and relocation Activities include Grading & Excavating Backfilling & Compacting Laying base courses Stabilizing the soil Setting up slope protection Establishing erosion control 17  18 Grading Valuable topsoil should be carefully Is changing the landform of a site using removed, covered, and stockpiled heavy equipment before grading Leveling of area for building/structures Creating a level plane can be Creating movement paths accomplished either by Create drainage and landscape features cutting – soil is removed from a Rough grading is leveling of ground for slope to increase the area for excavation and construction of the building building construction filling – soil is imported to fill lower Equipment for grading: levels to increase the area for o grader building construction o front-end loader cut and fill – preferred method, balances o backhoe 18  19 Excavation Excavation depth depends on the type of soil A sloped excavation side can be used for shallow excavation in a large site. Bench system can be used for a deep excavation. 19  20 Sheeting Steel sheet piling with interlocking A method of supporting soils from caving in steel sheets are driven or vibrated Done in the form of sheet piling, lagging, into the earth before excavation and slurry walls begins. Sheet pile may be wood, aluminum, steel, On wider excavations, cross-lot vinyl, or precast concrete placed vertically bracings supported by vertical steel into the ground. posts driven into the ground or Vertical steel columns (soldier piles) driven rakers that are set on an angle to into the soil and horizontal wood lagging is transfer the forces to a footing set in then placed between them to contain the the bottom of the excavation. excavation. 20  21 Tiebacks A method of securing sheet pile on a wide construction site to avoid any obstructions Option 1 – on a firm soil/rock o a steel cable is inserted into a hole drilled through the sheeting and into the rock or subsoil; o the drilled hole is filled with concrete grout and set to dry; o then the cable is tightened with hydraulic jacks and fastened to the wale to allow excavation. Option 2 – on a loose soil o a screw anchor installed with rotary drilling equipment; o it is quick, no hole drilling or grout injection required; o good in loose sandy and clay soils where a drilled hole may collapse; o screws can be withdrawn and reused. 21  22 Slurry wall – using cast-in-place concrete Protects the excavated area and becomes part of the permanent foundation. Caste-in-place wall: o excavation is dug with a narrow clamshell bucket; o excavation is filled with slurry of bentonite clay & water to stabilize the walls. o At required depth, a welded cage of steel reinforcing is lowered into the cavity o Concrete poured from the bottom of the excavation pushes the slurry up o Once the entire wall is poured & cured to sufficient strength, excavations begin from the inside. o As the excavation deepens, steel tiebacks are set in holes drilled through the wall & into the soil 22  23 Soil Anchor Metal shafts grouted into holes to stabilize the sides of an excavation. Involves drilling holes into the soil embankment and filling the hole with grout. Then a soil nail, typically a section of steel reinforcing bar, is pushed into the grouted hole. 23  24 Cofferdam Temporary watertight enclosures used in water-bearing soil or directly in water. Prevent water from entering construction area Water is pumped from within the cofferdam to keep it dry. Typically built using sheet piling, soldier beams with lagging, or as a double-wall structure. Extends through the areas of permeable water-bearing soil, through any impervious rocks that have low bearing capacity, and on to solid bedrock that is used to support the foundation. 24  25 Caisson A watertight shell in which construction work is carried out below water level. May be open or pneumatic. Open caisson The top is exposed to the weather, and work is performed under normal atmospheric pressure. Pneumatic caissons Air and watertight Open on the bottom so soil excavation can be accomplished. As an excavation proceeds, the caisson is consistently filled with pressurized air to keep water from entering The structure forming the caisson is frequently left in place and filled with concrete, forming a caisson pile. 25  26 Underpinning To support an existing building when constructing new building very close to it. 1. The use of trenches trenches are dug at intervals beneath the existing foundation. the building is supported by the remaining undisturbed soil. underpinning is installed in the trenched area additional trenches are dug through the unexcavated area. this is repeated until adequate underpinning is provided 2. The use of needles Needles are heavy wooden timbers or steel beams that run horizontally through the wall of a building and supported on each end. Spacing between needles is determined by an engineer 26  27 Paving Is a surfacing type for vehicular or pedestrian traffic use Common materials: Portland cement concrete, asphalt concrete, stabilized soil, gravel Flexible pavement layers Compacted subgrade – consolidated by compacting the natural subgrade Sub-base course – selected soil, provide additional support, load distribution Base course – high quality granular materials, often treated with bitumen for bonding Wearing surface – provides good ride quality Rigid pavement layers Compacted subgrade – consolidated by compacting the natural subgrade Base course – high quality granular materials, often treated with bitumen for bonding Concrete paving – reinforced, thick, strong, carries most of the traffic loads Wearing surface – provides good ride quality 27  28 Buildings have three major elements Superstructure:- Portion above the ground, directly supports service loads Substructure:- Enclosed portion below grade, supports load from superstructure Foundation:- Supports and transmits the load acting on it into the soil bearing below. Classification of foundations based on the depth of the base Shallow foundations – spread footing (pad, strip) & slab (raft), close to existing grade Deep foundations – piles, shafts, caissons, extend to reach firm/strong soil/rock Classification of foundations based on load transfer mechanism Spread foundation – transfers load by spreading over the underlying support Driven pile foundation – transfers load bearing & friction Drilled pile foundation – transfers load bearing 28  29 Choice of foundation system depends on Type and size of the building, Soil and subsurface water conditions Building code requirements Foundation should be placed below frost line to prevent possible heaving of the structure due to freeze-thaw of the bearing soil. Spread footing is an enlarged base of a stem (column) that transmits building loads to the soil. Strip footing is an enlarged base of a stem wall continuous around the perimeter of a structure. Combined footing is a spread footing that supports two or more columns close to each other or one column is located close to property line. 29  30 Slab on Grade Reinforced concrete slab placed directly on the ground to provide structural support Can be constructed with thickened portion at the edges or under load-bearing partitions and columns Minimum slab thickness is 4 in., can increase up to 6 in. for heavier construction Slabs can be constructed as an extension of a stem wall to provide a monolithic construction. 30  31 Slab on Grade Construction procedure: i. Ground is compacted to get firm bearing surface ii. Formwork is built at slab edge iii. 4- to 6-in. bed of compacted fill gravel is laid to get solid & well-drained base iv. Moisture barrier is laid to protect the slab from ground moisture v. Rigid insulation can be laid under the slab and along the vertical perimeter stem walls vi. Reinforcing bars or steel mesh is placed vii. Plumbing, heating, and other utility lines are placed viii. Concrete is poured 31  32 Mat/Raft Foundation Thick RC slabs that cover the total footprint of a building. Spreads the weight of the building evenly over the entire contact area Useful when soil characteristics have low bearing capacity or vary across the area. Recommended if spread footings would cover more than 50 percent of the building footprint area The entire slab is poured monolithically and continuously to avoid construction joints 32  33 Combined Footing Are used to support walls/columns near the property line The combined footing ties the outside row of columns to the next row within the building. Prevents uneven settlement or rotation if an isolated footing with the column placed on its edge were to be used A beam rests on independent footings and cantilevers over the outer footing to support the column. The footings may be reinforced concrete or steel grillage. 33  34 Deep Foundation Used when load-bearing capacity near the surface is not adequate Commonly used for high loading conditions, when soft or compressible soils are found near grade, or when firm soil is underlain by soft or compressible soil below. Piles:- Long and slender members that bypass soil of low bearing capacity to transfer loads to deeper soil or rock of high bearing capacity End-bearing piles Skin-friction piles Driven piles Drilled/bored piles 34