3 Flashcards
Why are horizontal forces more critical than vertical in seismic design?
Because structures usually have considerable reserve for dealing with additional vertical loads.
What is design wind pressure?
Minimum value for static pressure on exterior surface.
Account for exposure conditions, height, gust, geometry.
What is a moment force? What is a Couple force?
moment: tendency of a force to produce rotation about a point or line
Couple: two equal parallel forces acting in opposite directions tending to produce rotation, not translation.
Describe the following three frames: Fixed Frame, Hinged Frame, Three Hinged Frame
Fixed Frame - Rigid Frame - fixed joints, resistant to deflection. Sensitive to settlement and thermal expansion/ contraction
Hinged Frame - Rigid Frame - pin joints, reduce bending stress, allow rotation
Three-hinged Frame - two rigid frames connected to support with pin joints, most sensitive to deflection - least affected by settlement and thermal stress
Name beams (wood,steel and concrete) that can span >60’ (18m):
Wood = laminated beam (timber), trusses
Steel = OWSJ + trusses
Concrete = precast tees
3 mechanisms for resisting lateral loads:
Rigid frames - steel or reinforced concrete with rigid joints (least effective to achieve lateral stability. Only use in low-mid rise buildings)
Shear walls - wood/ concrete/ masonry - resists change of shape and transfer loads to ground.
Braced Frame - timber/ steel - knee brace, k-brace, cross brace
What do vents and traps do in plumbing?
Vents permit septic gases to escape and prevent siphonage and backpressure
Traps seal sewer gases from escaping the fixture
List considerations in specifying and designing HVAC systems:
Performance - technical and cost efficiency (operational and capital cost)
fuel/ power source - regional availability and efficiency
Flexibility - to meet various demands
Noise and vibration - related to adjacent spaces/ programme
Space consumption - how much room/ area is required and configuration
What is the intent of a fire protection system?
Contain fire long enough for safe evacuation of occupants and long enough for firefighters to respond
Why are wet-pipe sprinkler systems the most common?
Easy to design, install, maintain and cost less
List ways to improve consistency/ bearing capacity of soil:
Bearing capacity - deepen and/or widen footing
Drainage - drain area to improve soil characteristics
remove/fill - remove unstable soil, fill with compact granular material/ engineered fill
Compaction - mechanically compacted
What are cohesive and non cohesive soils? Example of each.
Cohesive soils - retain strength when unconfined
Granular soils - fall apart when not confined
What are shallow and deep foundations used? How do they work? Name 3 of each
Shallow foundations (strip, beam, SOG): use when stable soils of adequate bearing capacity are present at ground. – transfers load directly to soil near the lowest part of the building.
Deep foundations (piers, piles, walls): use when soil is not stable at ground, extend foundation to more stable medium. – transfer load by end-transfer and adhesion/ friction of soil.
Factor to consider when designing foundations:
- Subsurface soil/ ground water conditions
- Structural requirements - load, configuration, depth/ adjacent property
- Construction method - access, site space
- Enviro factors - weather, slope condition
- codes/regulations
List functions of the foundation system:
- Transfer building loads to ground
- Anchor building against wind/seismic loads
- Isolate building from frost heaving/ expansive soils
- Basement can also serve as liveable space/ storage/ mech
How is condensation minimized in regards to building envelope?
Minimized by placement of thermal insulation and VB/ vapour retarder within an assembly and proper ventilation of concealed spaces (attics, walls, crawl spaces)
What are the 4 D’s when it comes to liquid water resistance?
Deflection, drainage, dryness, durability
Explain cladding systems in regards to moisture control: concealed barrier, rainscreen systems, pressure moderated rainscreen.
Concealed barrier: (drained cavity systems) shed most water at cladding face, with a membrane behind to let water run down and out (not pressure equalized)
Rainscreen systems: similar to concealed barrier but with large gap
Pressure moderated rainscreen: cladding vented to promote air flow to pass through
What 3 factors help in increasing sound transmission loss (TL)?
Separating into layers - staggered stud/ double studs; resilient mounting; air space; seal pipes/ penetrations to maintain continuity; spacing studs (from 400mm oc to 600mm oc can increase STC by 1-2 points)
Mass - heavier/ more dense the greater the TL
Adsorption - soft/ absorptive materials (if using sound insulation in cavity wall, stagger studs or use resilient channel insulation in these assemblies can add up to 10 STC points)
What are two main types of sound sources between spaces? And ways to mitigate?
Airborne - mitigate with mass/ insulation/ isolation
Impact - mitigate with discontinuity of materials
List 4 ways to reduce sound transmission of equipment:
1 Block paths through plenum spaces (ductwork/ piping), vibration/sound dampers
2 Use resilient mounting and isolate equipment from building structure - reduce transmission of vibration through supporting structure
3 Inertia block - heavy concrete base for equipment
4 Select equipment with low sone rating
What is Apparent Sound Transmission (ASTC)? 2 examples of each
Direct transmission = sound through wall (STC rating) factors: insulation, mass
Flanking (indirect) transmission = sound going around walls (through floor/wall connection) factors: joist direction, floor topping, continuity of subfloor through wall
What are the 5 types of Portland cement used for
Type I - normal - used for general construction
Type II - moderate - general construction where resistance to moderate sulfate (water/soil) is required, or where heat buildup can be damaging (ie large piers and heavy retaining walls)
Type III - high-early strength cement cures faster and gains strength faster than normal cement. Used when early removal of formwork is desired, or cold-weather construction to reduce time required for heat protection
Type IV - low-heat cement - generates less heat of hydration than normal portland cement. Used in construction of massive concrete structures (ie gravity dams)
Type V - sulfate resisting - required when resistance to severe sulfate action is required
What % of concrete is aggregate? What properties does it give the final product?
60-80% – strength, weight, fire resistance
What is the difference between coarse and fine aggregate?
Fine = sand with particles ¼”
Coarse = crushed stone, gravel, blast furnace slag > ¼” (relevant for reinforce concrete - max size is limited by the area and spacing of rebar)
Explain what the following admixtures do: Air-entraining agents; Accelerators; Retarders; Surface-Active Agents; Water-reducing agents; colouring agents
Air-entraining agents - air bubbles into mix - increase workability, improve resistance of cured product to cracking/ scaling. In large amounts - can produce lightweight insulating concrete
Accelerators - hasten setting/ strength development of a mix
Retarders - slow the setting/ strength of a mix, more workable time
Surface-active agent - reduce surface tension of mixing water into mix (emulsifying)
Water-reducing agent - reduce amount of mixing water required for desired workability (lower ratio generally increases strength)
Colouring agents - pigment or dye to alter colour
What does water cement ratio (of cured concrete) control?
Strength (compressive strength), durability, watertightness – for most applications, ratio should be 0.45 - 0.60
Why is steel reinforcement required in concrete (5 things)?
Absorb tensile, shearing and some compressive stresses
Tie vertical and horizontal elements
Reinforce edges around openings
Minimize shrinkage / cracking
Control thermal expansion/ contraction
What are 3 types of face brick ?
FBX - minimum variation in size/ colour etc
FBS - wide range of colour/ variation
FBA - nonuniformity in size/ colour/ texture
What are 4 types of mortar?
Type M - high strength - high lateral or compressive loads or severe frost action
Type S - medium-high strength - high flexural bond - normal loads
Type N - medium strength - general use above grade
Type O - medium-low strength, non-load bearing interior walls/ partitions
What is non ferrous metal? Vs ferrous metal?
Non ferrous = no iron (copper, aluminum, lead)
Ferrous = with iron (steel, cast iron, wrought iron)
How are tensile and compressive forces best handled for wood grain?
In a direction parallel to the grain
What moisture must wood be at to be decay-resistant?
Moisture content is <20%
5 types of insulation (and rough r value of each)?
Loose fill ~R3/inch
Batt (or blanket) ~ R3/inch
Rigid ~R5/inch
Spray ~R6/inch
Cast ~R1.5/inch
What are 4 principles to control layers in a wall?
Rain control - ie cladding
Air control - ie AB
Vapour control - VB
Thermal control - insulation
Discuss mass as it relates to sound transmission through GWB.
Mass (density) reduces sound transmission (more dense = better STC)
Doubling GWB weight can add 10 points to STC rating (weight not thickness)
Add more layers (from 1 to 2) – not internal layers, keep cavity depth
Firestop vs. Fire block
Firestop = material/ components used to fill gaps/ penetrations at fire separations (ie intumescents, silicone, rubber, cementitious)
Fire block = material/ components used to restrict spread of fire within or from a concealed space
What is the main cause of water infiltration into a wall assembly?
Pressure difference across the wall assembly - high pressure (high humidity) at interior migrates to low pressure (low humidity) at exterior, without a VB condensation forms in insulation then leads to mold
3 methods of specifications
Proprietary - trade name
Prescriptive - detailed statement about products, system, material (arch is liable)
Performance - describes how material/ system will perform/ end result. Ref standards (contractor liable)
Components of a specification:
General - Summary, References, Definitions, admin/ tech requirements (System Description, Submittals, Quality Assurance, Delivery/Storage/Handling, Project/ Site Conditions, Sequencing, Scheduling, Warranty, System Start-Up, Owner’s Instructions, Commissioning, Maintenance)
Product - equipment, fixtures, materials, finishes, mixes, components, manufactures/ fabrications - all to be incorporated in the work
Execution - Installers, Examination, Construction Reinstallation, Field Quality Control, Adjusting, Cleaning, Demonstration, Protection, Schedules
What is the function of the working drawings?
Communicate building design into a graphic format, illustrate extent, location and quantity of various building elements. Must include - location of components (detail bubble); name/ identification of the components; shape and form of design; details of connections/ joints
Until ready to be issued as bid or contract documents, often referred to as “progress” documents (drawings or specifications). These interim versions of design information are used to communicate and distribute information within the design team and to others, as appropriate at various stages of development or as needed.
MasterFormat divs specific to each discipline:
Architectural 00-14, 31, 33
Structural 00-06
Mechanical 00-01, 21-25
Electrical 00-01 26-28
Civil 00-01, 31-33, 35
Services 00-01, 14, 21-28
What are 6 types of sound that can reach a listener?
Incident sound (mirror/ reflects)
Diffracted sound (bent by obstacle path)
Airborne sound (direct source)
Attenuation from source (amplitude as it spreads)
Echoes (reflected)
Convergence of sound waves from concave surface
List 3 types of strengthened glass:
Tempered = 3-5x more resistant to fail. Impact along edge will shatter sheet
Heat strengthened = stronger than annealed glass, less susceptible to shatter due to edge impact
Laminated = holds together if broken, can be used for solar heat control, sound control, blast resistance
List 4 ways to prevent moisture infiltration:
Sills and drip edge
Drainage holes in cladding
sealants/ gaskets
Lapped and locked joints
What STC rating does NBC rqr for dwelling units?
STC 50
STC ratings:
Normal speech through wall = 25
Loud speech heard through wall = 30
Loud speech heard but not understood = 35
Loud speech faint through wall = 42-45
Loud sound heard through wall = 46-50
Soundproof = +65
How does ASTME define soil types?
Description (silty gravel)
Bearing capacity ( 5000 psf)
Susceptibility slight (slight)
Permeability + drainage (poor)
Describe layers of a typ concrete slab assembly:
100mm slab thickness
Welded wire/ rebar - reinforcement
6 mil poly
50mm sand
100mm min base gravel/ crushed stone
Stable uniform dense soil
3 main concrete joints?
Isolation (expansion) = allows movement between slabs and adj columns
Construction (control/ isolation) = construction stop and start again, keyed or doweled
Control = lines of weakness so cracking can occur at predetermined lines (space ~15’-20’)
Pros of wood as a structural material:
Easy to work with
Renewable
Flexible
Light
Exposed timber
Good in compression and tension
Pros of concrete as a structural material:
Freedom of form
Fire protected
Exposed structure
Inexpensive
Good in compression - must be paired with reinforcing for tension
Pros of steel as a structural material:
Modular
Long spans
Light
Stiff and elastic
What is lightweight concrete made of? What is insulating concrete made with?
Lightweight = Expanded shale or slate aggregate
Insulating = Perlite aggregate or foam agent
MasterFormat is subdivided into hierarchy, list 4 main org structures
-divisions
-sections
-parts (1. General 2 products 3 execution)
-articles (major subject comprised of paragraphs)
How does a heat pump work? Pros and cons?
transfers heat from warm to cool space
pros: efficiency, electric, comfort/ quality
cons: higher capital cost, only for moderate climates (not as good for cooling), can be noisy
what is the role of the project manual?
should provide all of the information required to:
prepare confident bids or accurate construction cost estimates (quantity & type of materials, application);
obtain the building permit and other approvals from authorities having jurisdiction;
plan and direct the sequence of construction work across all trades in a manner appropriate to the achievement of workmanship and performance requirements for the project.
What are the contents of the project manual
bid requirements (invitation, info, instructions, bid forms, bid security forms)
contract forms (agreement, performance bonds, payment bonds, certificates)
contract conditions (general and supplementary)
specifications
Flashing locations
- Roof valleys, ridges, hips, change in roof pitch
- roof penetrations (chimneys, roof drains, vent pipes and skylights)
- window and door openings
- roof eaves and rakes
- floor and wall intersections
- intersections between roofs and vertical surfaces
- where building meets ground
- expansion joints and other breaks in building skin
