SS 8

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SS 8
2014-03-22 23:13:50
ARE exams

ARE exams
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    • Moment of inertia
    • Measure of an object's resistance to change its rotation
  1. Section modulus
    The ratio of a cross section's second moment of area to the distance of the extreme compressive fibre from the neutral axis
  2. Yield point
    The amount of stress that causes a material to deform without additional load added
  3. Shear
    A strain produced by pressure in the structure when it's layers are lateral shifted in relation to each other
  4. What is allowable tension for structural steel?
    22,000 psi
  5. What is usable compression in bearing for concrete?
    900 psi
  6. What is allowable compression parallel to grain for structural lumber (Doug fir)?
    1,150 psi
  7. The measure of bending stiffness of a section is called...
    ... moment of inertia
  8. Gage line
    Standard dimension from corner edge of an angle to centerline of bolts holes. Depends on size of angle
  9. Joists
    • Width: 2" nom
    • Spacing: 12-16" oc
    • Spans: 20-25ft
    • Top/Bottom: bridging supports bottom edge, sheathing holds top in place
    • Use: between beams or bearing walls
    • Advantage: tried and true method
  10. I-Joists
    • Width: 1-3/4" to 3-1/2"
    • Spacing: 12"-24" oc
    • Top/Bottom: 9-1/2"-16" depth OSB webs and microllam (thick plywood) flanges connect to wall with hangers
    • Use: residential/light commercial
    • Advantage: Efficient standard shape as shop fabrication eliminates common defects
  11. Glulam
    • Width: 3-1/8", 5-1/8", 6-3/4", 8-3/4"
    • Spacing: varies
    • Spans: 15' to 60'
    • Top/Bottom: Several layers of timber bonded together with glue and connected with plates and/or bolts
    • Use: Columns and beams commercial public
    • Advantage: can be left exposed, can be tapered or curved
  12. Plank/Beam Framing
    • Width: 4" or 6"
    • Spacing: 4' or 6' or 8'
    • Spans: 10' to 20'
    • Top/Bottom: Wood decking span between beams, underside finish ceiling
    • Use: Between girders or bearing walls, residential
    • Advantage: easy to insulate
  13. Truss
    • Width: varies
    • Spacing: 24" oc
    • Spans: 24' to 40'
    • Top/Bottom: 12-36" depth made of strand wood members connected with plates
    • Use: residential, commercial, public
    • Advantage: MEP can pass thru
  14. Box Beam
    • Width: up to 30"
    • Spacing: varies
    • Spans: 50'
    • Top/Bottom: Plywood panels glued and nailed to 2x4
    • Use: residential, commercial, public
    • Advantage: looks like solid timber, custom made
  15. beam and girder system
    larger girders carry intermediate beams which support a slab with spans of 15'-30'
  16.   one way concrete joist system (pan joists)
    • -prefab metal pan forms are used to create frame to support light/medium loads with spans of 20'-30' and depths 1'-2'
    • -formed with prefab metal pan forms spaced 24"-36" apart in one direction
  17. two-way concrete joist system
    • -like one way joist but with beams in each direction
    • -typically used in rectangular bays where distance between columns is equal (or close to) in both directions
  18. flat plate system
    • -basically a two-way slab with no supporting beams, only columns
    • -reinforced slab spans in both directions directly into columns at 25' with 6" -12" thickness
    • -typically used for light loads, short spans, when floor-floor height must be minimized, and/or when simple under-side appearance is required
    • -has low shear capacity and low stiffness
  19. drop panel system
    -like a flat panel system, but the slab is increased around the columns for greater shear failure resistance
  20. flat slab system
    a two-way slab with column captials, drop panels, or both with spans of 30'
  21. waffle slab system
    • -ribs formed with reusable prefab metal/figerglass forms and span up to 40'
    • -provides the largest spans of covential concrete floor systems
  22. lift-slab system
    -floor/roof slabs are cast on top of the previous and then jacked up to the desired height
  23. single tee/double tee system
    • -prestressed ribs (one or two) with a 2" topping slab connected
    • -typically used for larger spans
  24. trusses
    • -typical depth-to-span ratios range from 1:10 to 1:20
    • -typical spans: 40'-200'
    • -typical spacing: 10'-40' oc
  25. if a building has irregular form and you want simple floor and roof framing fabricated onsite.. then your options are:
    • -sitecast concrete with any slab system without beams/ ribs
    • -light gauge steel framing
    • -masonry with concrete slab/wood light floor framing
  26. if a building has irregular column grid and you want something without beams/joist in the floor or roof. then your options are...
    • • Site cast concrete 2 way flat plate
    • • Metal space frame
  27. if a building has exposed structure and you want fire/heat resistance. then your options are...
    • • All concrete systems (except ribs)
    • • Heavy timber frame
  28. if a building has min floor thickness or min total building height and you want the thinnest floor system. then your options are...
    • • Prestressed Concrete slabs
    • • Site cast concrete 2 way flat plate
    • • Posttensioned 1 way slab
  29. if a building has min area occupied by columns and/or bearing walls and you want long span system. then your options are...
    • • Heavy wood trusses
    • • Glue lam wood beams
    • • Glue lam wood arches
    • • Steel frame
    • • Stell trusses
    • • Open Web Strutural Joinsts
    • • Waffle Slab
    • • Single or Double Tee Concrete
  30. if a building has changes in use over time and you want short span, one way systems that can easily be modified. then your options are...
    • • Light Gauge/Conventional Steel Frame
    • • Wood systems (including masonry)
    • • Site Cast 1 way concrete slab
    • • Precast concrete slab
  31. if a building has exposure to adverse weather and you want no reliance on onsite chemical processes. then your options are...
    • • Steel
    • • Wood
    • • Precast Concrete without toppings or grouting
  32. if a building has minimal off-site fabrication time and you want on-site construction with easily formed materials. then your options are...
    • • Sitecast concrete
    • • Light Gauge Steel Framing
    • • Platform Framing
    • • Masonry
  33. if a building has minimal on-site erection time and you want a lot of prefab/modular components. then your options are...
    • • Single story rigid steel frame
    • • Steel frame with hinged connections
    • • Precast concrete
    • • Heavy tibmer frame
  34. if a building has 1-2 stories with minimal construction time and you want lightweight/easy to form/prefab. then your options are...
    • • Any steel
    • • Heavy timber frame
    • • Platform frame
  35. if a building has 4-20 stories with minimal construction time and you want lightweight/easy to form/prefab. then your options are...
    • • Precast concrete
    • • Conventional Steel Frame
  36. if a building has 30+ stories with minimal construction time and you want strong, lightweight, easy to assemble. then your options are...
    •  • Steel Frame
    • • Sometime Site/Precast Concrete
  37. if a building has minimal diagonal bracing or shear walls and you want a rigid joint system. then your options are..
    • • Site cast concrete (With beams/deep slab around columns
    • • Single frame w/welded connections
    • • Single story rigid steel frame
  38. if a building has minimal dead load foundation and you want lightweight/short span. then your options are...
    • • Any Steel
    • • Any Wood
  39. if a building has minimal structural distress due to unstable foundation and you want frame without rigid joints. then your options are...
    • • Steel frame with bolted connections
    • • Heavy timber frame
    • • Precast concrete system
    • • Platform framing
  40. if a building has concealed spaces for MEP and you want to not add height to the building. then your options are...
    • • Truss
    • • Open web joists
    • • Light Gauge Steel Framing
    • • Platform Framing
  41. dowel type fasteners
    -nails, screws, bolts that transmit lateral loads via bearing stresses between the fastener and members of the connetion OR that transfer withdrawal loads parallel to the fasteners axis via friction or bearing to the connected materials
  42. bearing type fastners
    -shear plates that transmit lateral loads only by shear forces via bearing on the connected materials
  43. hangers
    combination of dowel and bearing type fasteners that support one structural member and are connected to another member by a combination of dowel and bearing action
  44. plate girder
    assembly of steel plates, or plates and angles, fastened together to form an integral member
  45. underpinning
    the process of strengthening and stabilizing the foundation of an existing building
  46. shoring
    supporting a structure in order to prevent collapse so that construction can proceed.  (e.g.: support beams and floors of building while a column/wall is removed, shoring in trenches for worker safety in excavation)
  47. counterforts
    reinforced concrete webs act as diagonal braces
  48. nail sizes
    • *penny size (d)
    • 2d = 1”
    • 6d = 2”
    • 10d = 3”
    • 20d = 4”
    • 40d = 5”
    • 60d = 6”
    • •Box nails: 6d - 40d, smallest diameter
    • • Wire nails: 6d to 60d, medium diameter
    • • Wire spikes: 10d - 8.5” with 3/8” diameter, largest diameter
  49. lag screws/bolts
    • • Diameters (measured at the non-threaded shank): 1/4” to 1 1/4”
    • • Lengths: 1” – 12”
  50. Electrical Arc Welding Process:
    (most common) one electrode from power source is attached to steel member being joined while other is the welding rod.  Heat generated by the arch formed by arc when welding rod is brought close to members and base metal and the end of the electrode melt into the joint and the materials fuse together
  51. weld symbol above means...
    ...the weld is on the opposite side of the leader
  52. weld symbol below means...
    ... the weld is on the same side as the leader
  53. Coefficient of Thermal Expansion:
    ratio of unit strain to temperature change, a constant, given for each material.
  54. Fatigue: 
    progressive damage that occurs when a material is subject to cyclic loading
  55. Creep: 
    tendency of a material to move slowly or deform permanently under stress
  56. Moisture Content:
    weight of water in wood as a fraction of the weight of oven-dry wood
  57. Hydration:
    chemical hardening of concrete
  58. Abrams Law:
    compressive strength of concrete is inversely proportional to ratio of water to cement
  59. Laitance:
    an accumulation of fine particles on the surface of fresh concrete due to upward movement of water.  Occurs when there’s too much water in the mixture.  Concrete appears “chalky”
  60. moisture content for wood
    • • Dry lumber max moisture content = 19%
    • • Kiln dry lumber max moisture content = 15%
  61. unavoidable notches in wood
    • Notches can’t exceed 1/6” the depth and can’t be located in the center third of the beam
    • • Notches at supports can’t exceed 1/4” of the beam depth
  62. what is most common type of steel used in structures
    ASTM A572 grade 50
  63. Type I concrete
    standard cement used for general construction
  64. Type II concrete
    modified cement where heat of hydration needs to be controlled
  65. Type III concrete
    high early strength cement where quick set is required
  66. Type IV concrete
    low heat cement for very slow setting, used to avoid damage caused by heat
  67. Type V concrete
    sulfate resisting cement, where exposed to water or soil with hight alkaline content
  68. concrete minimum water to cement ratio
    .35 - .40 by weight (4 gallons per 94lbm sack of cement)
  69. Standard concrete weight                            
    150 lb./ft3
  70. Lightweight structural concrete weight                              
    80 - 120 lb./ft3
  71. Non-structural insulating concrete weight                         
    50 - 80 lb./ft3 
  72. concrete admixture - Plasticizers:
    reduce the amount of water required while maintaining consistency for placement/compaction.  Reducing water makes it possible to mix higher strength concrete
  73. concrete admixture - Fly ash
    waste material obtained from coal fired power plants, increases strength, decreases permeability, reduces temperature rise, improves workability
  74. rebar should be located at a min distance from exposed edge
    • • Slabs and walls = 3/4” distance from face of conc
    • • Beams and columns = 1 1/2” distance from face of conc
    • • Exposed to weather or in contact with soil = 1 1/2” distance from face of conc
    • • Exposed to weather or in contact w/soil (larger than No. 5 rebar) = 2” distance from face of conc
    • • Concrete poured direction on soil = 3” distance from face of conc
  75. Wash boring:
    the drilling of a test hold to locate bedrock beneath very compact soil.  A pipe is driven into the soil while water forces the material to the surface.  It can penetrate all materials other than rock.
  76. Auger boring:
    soil testing that uses an auger drill big fastened to a rod to bring the soil to the surface. Most efficient in sand and clay because the bit is easily obstructed.  It has limited depth
  77. Orthogonal:
     to be in two horizontal directions at 90degrees to each other
  78. Downburst:
     An area of significantly rain-cooled air that, after reaching ground level, spreads out in all directions producing strong winds.  Associated with thunderstorms