5 - PDD Flashcards
what are 4 material characteristics that should be considered when selecting exterior materials for a building?
- properly used
- withstand elements
- how often does it require maintenance?
- how well does it perform for its intended use & longevity?
how should the performance of materials be considered during the design phase?
- tested to assure they will perform as expected
- life span, withstand normal wear & tear
how does building orientation affect natural daylighting?
- north = no direct sunlight
- south = fair amount year round
describe the treatments for a north facing window vs. east facing
- north: no direct light but an even glow from reflected light all day, in hot places they have almost no heat gain, in cold climates almost always cold and grey
- east: receive sunlight in morning, start warming building at beginning of day
describe the treatments for a south facing window vs. west facing
south: receive sunlight nearly all day; in hot climates use overhangs to block summer sun (a 2’ overhang will shade summer, but allow winter in)
west: receive hot afternoon sun until sunset, much lower in sky so overhangs dont help, use louvers to control
what is a free body diagram?
to analyze forces on and within structures, use this technique from physics (FBD)
representation of a body and all forces & moments acting on it - does not include internal forces
what structural connection can resist either x or y forces, but not moment?
pinned connections
this type of structural connection only resists forces in the y direction
roller connections
within any structural member in bending, _____ is quantified as the maximum translation measured perpendicular to its central axis
deflection: vertical distance that the beam sags at midspan
usually expressed as a fraction of the span (often noted as greek letter delta)
the formula for deflection of a beam with a uniformly distributed load is:
delta = 5 wl4 / 384 EI
the fibers within a beam develop an internal moment to resist the moment caused by deflection. this resisting moment is called:
bending moment
the centroid of an area is conceptually defined as:
the center of gravity of a mass
for simple geometric shapes, this is easy… for many common asymmetrical shapes, it is calculated
a factor relating the shape of a structural section and the distribution of its material relative to a chosen axis is called:
a section’s moment of inertia, usually denoted “I”
the units of moment intertia are in4 or inches to the fourth power
ratio of a sections moment of inertia and the distance between the neutral surface & outermost edge of the section, “c” is referred to as:
the section modulus
S = I / c
the 2 reasons that column buckling occurs are:
- if an applied load is eccentric, or if it doesn’t occur exactly at a column’s centroid, it will impart some degree of moment, causing bending
- no material is truly uniform in its internal composition; any very slight variation of the material will tend to allow buckling
finding this value quantifies a cross section’s ability to resist buckling under an axial compressive load by relating its moment of inertia & area
radius of gyration = convenient parameter, providing measure of the resistance of a cross section to lateral buckling
a load imposed on a structural member at some point other than the centroid of the section is called:
eccentric load
bending stress is a function of the section modulus and the:
bending moment
define slenderness ratio
ratio of a wall or columns unsupported height/length to its thickness (measures ability to resist buckling)
vertical steel reinforcing within reinforced concrete columns essentially are very slender _____ when compressive stress is applied
columns
a special kind of made up beam that uses members efficiently by placing them in pure compression or tension, when loaded properly, to carry loads over a span is called a:
truss
the two methods for manually analyzing trusses are:
- method of joints
- method of sections
in this type of truss analysis, a cut is made passing through no more than 3 members, and the 3 equations of equilibrium are applied
method of sections
forces acting toward a joint indicate a truss member is in:
tension
liquefaction
water saturated sediment temporarily loes strength & acts as a fluid
- must be space between particles that water can occupy
- dramatic impacts during an earthquake
- sands, muds, silts are most vulnerable (coastal)
seismic waves
oscillations at molecular level within the soil
- sudden relative displacement of very large masses & energy release results in waves rushing through surrounding rock & soil
- project outward from hypocenter and have different characteristics
- Primary/pressure waves, Secondary/shear waves, Surface waves
P waves
Primary/pressure seismic wave
- highest velocity, arrive first
- cause compression in soil in the direction of travel in alternating push-pull
- can travel through liquid
S waves
Secondary/shear seismic wave
- second highest velocity, arrive just after P wave
- cause shear in soil particles (motion perpendicular to direction of wave travel)
- damaging sideways & vertical accellerations
- can not travel through liquid
surface waves
- lowest velocity seismic wave, arrive after P & S waves
- veritcal displacement in earth’s surface
- last longer w/ larger amplitudes, can be very destructive
- near surface of earth (similar to ocean wave)
stabilizing moment
a building’s self-weight creates a moment in the opposite direction of its overturning moment
- load & resistance factor design
- allowable stress design
base shear
story shear = summation of design lateral seismic forces at levels above the story under consideration
base shear = sum of all story shears at the base
diaphragms at each story must transfer force received at that level, plus those from the levels above
what is SDC?
seismic design category
req’s for geotechnical investigations relating to seismic forces likely to be experienced at a site
what is fundamental period?
measure of the time an object takes to travel out and back once when a force has acted on it
“child on a swing”
what is a fault?
plane within rock that forms in response to stress, usually induced by tectonic plates
vertical, horizontal, or any orientation in between
slippage creates earthquake
an earthquake’s depth & its relative location to a building is often directly related to its_____
destructive power
theory of plate tectonics
holds that earth’s crust is made up of masses that float on molten rock below
cooled, solidified chunks of crust ride around freely
crustal conveyor belt
loop of creating crust at mid-ocean ridges and destroying it a subduction zones (liquid-to-solid / solid-to-liquid)
fault systems that are great distances from each other at either end of loop
the amplitude of any wave is proportional to ______
the energy the wave transmits
higher amplitude seismic wave = more energy, acceleration, force on building
a low ratio of width to height has what advantage for a building
minimizes tendency to overturn when acted on by lateral loads, including seismic
coefficient of friction
describes the ability to resist sliding, such as a footing transferring lateral loads to the ground
the higher the coefficient, the great the soil’s capacity to resist sliding
capacity to resist = coefficient x dead load (vertical) on the footing
a pendulum clock is an example of _____
resonance
propelled by its own weight; a mechanism imparts very small force to overcome friction, keeping it going at a constant rate
the magnitudes of seismic forces a building will experience are determined by:
- the building’s weight
- the maximum ground acceleration
once forces act on building, its overall configuration determines how the forces will be transferred to the ground
fundamental periods of buildings relate primarily to height. T or F?
true
appx. divide no. of stories by 10 to estimate the fundamental period in seconds
response spectrum
represents a building’s range of responses to ground motion of different frequency
(site response spectrum)
allows us to see how buildings of different fundamental periods will behave on the same site
one benefit of creating a response spectrum is:
- tells us the resonant frequencies at which a building will undergo peak accelerations
- design can be adjusted/tuned so building period does not coincide with site period of maximum response
what is SFRS?
seismic force-resisting system
vertical elements of a building that take seismic load from the diaphragms & transfer it to the ground
name 3 basic alternative types of vertical SFRS and their essential characteristics
shear walls: receive forces from diaphragms & transmit them to the ground
braced frames: receive lateral forces from diaphragms and transmit to ground; generally less resistance than shear walls, more ductility (detailing of joints will help)
moment-resisting frames: frame without diagonal bracing; resist lateral forces primarily by bending in beams & columns; require strong col-beam joints
regardless of group, any vertical SFRS must continue from roof to base without interruption to perform the best. T or F?
true
- decreasing horizontal dimension of SFRS from one story to another decreases its capacity
- eliminating SFRS from one story to another breaks the load path
- openings in shear walls reduce capacity & create stress concentrations
ductility
a material’s or system’s ability to undergo deformation without breaking, and while still carrying load (e.g. a metal spoon can be bent back & forth several times before it breaks, but a plastic spoon breaks almost instantly… metal is ductile, plastic is brittle)
steel & ductility
steel’s capability of withstanding load past the yield point on the stress-strain curve makes it a very ductile material
steel is often combined w/ other materials to add ductility, such as in reinforced concrete
steel is often used in seismic force-resisting systems in ways intended to add ductility
ductility in lateral force resisting systems (or the SFRS)
absorbs energy (desirable)
a building whose lateral force resisting elements are more ductile will have to resist smaller seismic forces than its less ductile counterpart
are shear walls generally considered ductile or non-ductile?
non-ductile - shear walls resist lateral forces by developing shear in their planar surfaces (generally rigid, least ductile of the SFRS groups)
are moment-resisting frames considered generally ductile or non-ductile?
ductile
moment-resisting frames are generally the most ductile of the 3 SFRS groups, least rigid
the san andreas fault is what type of fault?
transom fault or strike-slip
horizontal movements primarily
a building’s configuration:
is a large factor in its ability or inability to survive an earthquake
stress concentration
occurs when large forces are concentrated at one or a few elements of a building, such as a particular set of beams, columns, or walls
reentrant corners & offsets (e.g. setback roof) are examples of building forms likely to cause stress concentrations
idealized “regular” building configuration:
identical resistance on both axes (of a plan):
eliminates eccentricity between the centers of mass & resistance and provides balanced resistance in all directions, thus minimizing torsion
idealized “regular” building configuration:
continuous load path (vertically & horizontally)
- interruptions in load path always produce stress concentrations
- continuous load path minimizes stress concentrations
idealized “regular” building configuration:
symmetrical plan shape
- minimizes stress concentrations
- minimizes torsion
idealized “regular” building configuration:
arrangement of vertical SFRS elements
symmetrical & parallel arrangement of vertical SFRS
- arranged in 2 directions in plan
- in parallel on opposite sides
- minimizes torsion & stress concentrations
idealized “regular” building configuration:
uniform strength & stiffness at perimeter
reduces likelihood of torsion
idealized “regular” building configuration:
equal floor heights
- equalizes column & wall stiffness
- minimizes stress concentrations
idealized “regular” building configuration:
uniform sections & elevations
eliminates offsets, minimizing stress concentrations
idealized “regular” building configuration:
low ration of width to height
minimizes tendency toward overturning
define base shear
total design lateral force or shear at the base
the term that describes the ability of a structural system or element to dissipate energy beyond its elastic limit is:
ductility
ELFP
equivalent lateral force procedure
establishes how to calculate base shear
equivalent lateral force procedure:
seismic base shear:
V = C(s)W
V = seismic base shear
it is the sum total of all story shears - gives us total lateral force a building must resist
C(s) = seismic response coefficient
collects factors related to occupancy, soils at the site, ground acceleration
W = effective seismic weight of the building
equivalent lateral force procedure:
seismic response coefficient:
C(s)
used in calculating base shear
C(s) = S(ds)/(R/I)
S(ds) = 2/3 S(ms)
and
S(ms) = F(a)S(s)
so
C(s) = 2/3 [F(a)S(s)] / (R/I)
equivalent lateral force procedure:
design earthquake spectral response acceleration parameter at short period:
S(ds)
S(ds) is used in calculating seismic base shear w/ ground acceleration
S(ds) = 2/3 S(ms)
and
S(ms) = F(a)S(s)
- establish reasonable percentage of actual force to which we will design
- Fa = site coefficient (depends on site class)
- Ss = ground acceleration from maps or USGS website
equivalent lateral force procedure:
response modification coeffeicient: R
R is used in calculating seismic base shear
- greater ductility translates to a higher R value (shear walls = low; moment resisting frame = high)
- greater R = less seismic base shear
- lesser R = greater seismic base shear
in a basic sense, what must be considered when designing the structural system of a building?
vast range of physical loads also shape the elements of the structure
equivalent lateral force procedure:
site coefficients and adjusted MCE spectral response & acceleration parameters:
Sms
used in calculating seismic base shear (ground acceleration)
Sms = Fa * Ss Fa = site coefficient, reduces or increases acceleration depending on site class (soil characteristic) Ss = ground acceleration
equivalent lateral force procedure:
site coefficient: Fa
site coefficient
reduces or increases acceleration depending on site class
equivalent lateral force procedure:
mapped spectral response acceleration at short periods:
Ss
basis of acceleration
name some of the general types of luminaries
- surface mounted
- recessed
- suspended
- freestanding
- wall mounted
- accessory
per the IBC, if site soil conditions are not known in sufficient detail, what is the best site class category that can be used?
site class D: stiff soil profile
what is fluid mechanics in relation to wind design?
branch of physics that studies physical properties and behaviors of fluids, which teaches us about wind behavior
what is mean roof height?
average of roof eave height & height to the highest point on roof surface (except for roof angles of less than or equal to 10 degrees, the mean roof height shall be the roof eave height)
what is wall wash lighting?
smooth, even distribution of light over a wall
wind’s movement is primarily _____ ?
lateral
sometimes there are vertical components
what is an escarpment?
aka scarp - with respect to topographic effects, a cliff or steep slope generally separating two levels or gently sloping areas
locations w/ abrupt changes in elevation cause wind to speed up
Kzt factor
locations with abrupt changes in elevation are subject to _____
locations w/ abrupt changes in elevation cause wind to speed up
Kzt factor
what is design force, p?
equivalent static pressure to be used in the determination of wind loads for buildings
what is uplift?
upward acting force, results from wind passing over horizontal surface (roof)
what is basic wind speed?
V
3-second gust speed at 33’ above the ground in exposure c
- older codes used to give as average speed of a column of air one mile long
what is the MWFRS?
main wind force resisting system
assemblage of structural elements assigned to provide support & stability for the overall structure; generally receives wind loading from more than one surface:
- wind lateral loads
- wind uplift
- overturning
what is vortex shedding?
when a tall building is subjected to high winds, vortices are produced in sequence over time
what are vortices?
swirls of air created when wind is forced around objects, and are most noticeable when wind flows around taller buildings
building or other structure, flexible
slender buildings & other structures that have a fundamental natural frequency less than 1 hz
building or other structure, rigid
a building or other structure whose fundamental frequency is greater than or equal to 1hz
building, enclosed
a building that does not comply with the requirements for open or partially enclosed buildings
building, open
a building having each wall at least 80% open
building, partially enclosed
- total area of openings in a wall that receives positive external pressure exceeds the sum of the areas of openings in the balance of the building envelope (walls & roof) by more than 10 percent
- total area of openings in a wall that receives positive external pressure exceeds 4 sq.ft. or 1% of area of that wall, whichever is smaller, and the % of openings in the balance of the building envelope does not exceed 20%
basic wind speeds have been mapped and are available to use as a basis for determining wind loads. they’re given in miles per hour or ____?
meters per second
wind produces uplift, especially on ____?
roofs & overhangs
as defined in ASCE 7-05 chapter 6, an open building has____?
each wall at least 80% open
what are components & cladding?
elements of the building envelope that do not qualify as part of the MWFRS
the equivalent static force to be used in the determination of wind loads for open buildings & other structures is ___?
design force, F
tropical disturbances, hurricanes & typhoons, are examples of _____
tropical cyclones; originate over tropical oceans
chinooks & santa ana winds are examples of _____
down-slope winds; occur at leeward side of mountain ranges
buildings at risk identifies a total of 4 damage mechanisms through which severe windstorms damage structures. what are they?
- aerodynamic pressures created by flow of air around a structure
- induced internal pressure fluctuations die to breach in the building envelope
- impact forces created by wind-borne debris
- pressures created by rapid atmospheric pressure fluctuations (associated primarily w/ tornadoes)
the magnitude of pressure from wind (uniformly distributed load) is directly related to ____?
wind speed
in the most intense windstorms, debris impacts represent a significant portion of the damage caused, including _____?
injuries & loss of life
fluid dynmaics shows us that a fluid passing over an obstruction will cause uplift. this is called bernoulli’s principle. it acts on airplane wings and _____.
roofs & overhangs
what are special wind regions?
areas requiring detailed study to determine basic wind speed due to topographical & climatic conditions
in relationship to building design for wind forces, a building or structure having no unusual geometrical irregularity in spatial form is known as _____.
a regular-shaped building or strucutre
what is eave height, h?
the distance from the ground surface adjacent to the building to the roof eave line at a particular wall (average height if it varies)
how much effect do pressure fluctuations of the atmosphere (as opposed to inside building) have on most structures?
little to no effect
there are 3 allowed procedures for wind load analysis established in ASCE 7-05 chapter 6. what is method 1?
- simplified procedure
others are:
- analytical procedure
- wind tunnel procedure
1 & 2 are tabulated values & calculations
simplified design wind pressure is?
ps
- gives force per sq. ft. to use in design of the MWFRS
- cannot be less than 10lb/sqft
- horizontal pressures combine windward & leeward
- method 1: simplified procedure gives us ps
internal pressure coefficient
Cpi
- relates degree of enclosure & resulting internal pressures on the MWFRS
- requires 2 load cases to be tested: a positive & a negative Gcpi applied to all internal surfaces
method 1 = simplified procedure
C & C
net design wind pressure for exposure B at 30’ height from ground
Pnet30
gives base pressure per sq.ft. to be used in determining Pnet, the net design wind pressure for components & cladding, using method 1 - simplified procedure
method 1 - simplified procedure
MWFRS
simplified design wind pressure for exposure B at 30’ height from ground
Ps30
gives the base pressure per sq.ft. to be used in determining Ps, simplified design wind pressure for MWFRS, using method 1 - simplified procedure
a unit of illumination based on the metric system equal to 1 meter-candle or 1 lumen/sq.m.
lux
method 1 - simplified procedure
C & C and MWFRS
topographic factor: Kzt
- considers topography of site
- accounts for wind speed-up at escarpments or ridges & their distance from site
- K1 comes from a table, K2 & K3 can be calculated
- defaults to 1.0 if conditions are not met
method 1 - simplified procedure
C & C and MWFRS
adjustment factor for building height & exposure
adjusts simplified design wind pressure (for MWFRS) or the net design wind pressure (for C&C) based in a table graduated by building height in feet and exposure category
exposure category: B, C, or D is assigned based on surface roughness of the surroundings
what do MWFRS & MSFRS stand for?
main wind force resisting system
main seismic force resisting system
a non-symmetrical building is likely to experience what type of force under wind loads?
torsion
if there’s eccentricity between a building’s center of rigidity & resultant lateral wind force, torsion results
when a lateral force acts on a building, there is a tendency for it to tip over, this is referred to as:
overturning moment
overturning can be an issue when the lateral force is large or the building is _____
rigid
the building’s self-weight counteracts overturning moment w/ stabilizing moment
2 types of forces that create overturning moment have different origins. what is it for
- wind?
- seismic?
wind: consequence of a pressure multiplied by an area
seismic: consequence of accelerated mass, with each story contributing based on mass & height
in a multistory building, each story adds to the total overturning moment in proportion to what 3 factors?
- story shear
- height above the base
- weight
in seismic design, vulnerability to overturning is related to soil conditions. name 2 conditions to look out for:
- soils subject to liquefaction
- different soil types (differential settlement)
when overturning moment results from earthquake loads, E, the basic load combinations (in IBC) govern how resisting moment is compared to overturning moment.
using load & resistance factor design, we would compare ____D and 1.0E
using allowable stress design, we would compare ____D and 0.7E
- 9D
0. 6D
overturning from wind loads isn’t usually an issue for typical buildings. it can be a major consideration for which 2 types of structures?
tall or lightweight
overturning moment can be calculated in a simplified way, using the ____ design pressure multiplied by the ____ over which it acts
windward, area
due in part to higher W factors, a building’s ratio of width to height can matter more when designing to resist wind loads, rather than seismic loads.
a __,___ building, relative to the direction of wind loading has advantages in moment arm length
wider, lower
greater width means longer moment arm for dead load, increasing resisting moment
less height means less area & lower magnitude of lateral force
because their purpose is to achieve grade changes by holding back earth, retaining walls must resist lateral forces caused by what 2 factors?
- weight of soil retained
- weight of ground water if present
3 types of forces a retaining wall must resist:
- overturning
- sliding
- soil pressure
this type of retaining wall uses only its own dead load to resist forces; can be built of stone, masonry, or plain or reinforced concrete
gravity wall
roofs & floors generally act as ____ and carry lateral load
diaphragms
when plywood is used in wood construction to create diaphragms, special attention should be paid to what?
nailing patterns
prescribed by building code, described for field & edge conditions, spaced closer at edges
if provision for drainage isn’t made for a retaining wall, hydrostatic pressure based on the weight of water must be added to the soil load. such loads in addition to those from the soil are called:
surcharges
this type of retaining wall uses perpendicular buttresses, usually combined w/ cantilever wall, usually occur at retained side & are buried in backfill, usually higher than cantilever walls
counterfort walls
this type of retaining wall combines a wall with tension ties to the retained rock or soil
tie-back or anchored wall
rock or soil is drilled & injected w/ reinforced concrete, or steel cables attached to an expanding anchor
most commonly cantilever design, usually for high loads & tall heights, such as highway cuts
_____ pressures are allowed to apply where the top of a wall is free to move, such as a retaining wall
active
_____ pressures, which are higher, apply where the top of the wall is not free to move, such as at a foundation wall with a floor structure attached like a basement
at-rest
for retaining walls, the IBC typically requires a factor of safety of what?
1.5 for each mode of failure
in a cantilevered retaining wall, the _____ resists lateral pressure by creating moment
heel
how is the soil’s lateral pressure distributed on retaining walls?
triangular pressure w/ 0 on top and max at bottom
resultant force occurs at 1/3 the height, creates overturning moment
the edge members or beams of a diaphragm (roof or floor) are referred to as:
chords
receive their load as a uniformly distributed load per linear foot, react w/ bending moment & shear, just like a beam
just as with gravity loads, the foundation ultimately transfers all lateral loads to:
the earth
lateral loads & related uplift on a foundation’s ability to resist these loads depends on which 2 factors?
coefficient of friction & lateral bearing capacity
this type of wall is required to resist the lateral pressure of retained soil:
retaining wall
a diagonally braced frame in which at least one end of each brace frames into a beam a short distance from a beam-column or from another diagonal brace is known as:
eccentrically braced frame (EBF)
name 3 forms of intrusion detection
- perimeter protection
- area or room protection
- object protection
what are 4 methods of perimeter building protection?
- magnetic contacts
- glass break detectors
- window screens w/ embedded wire
- photoelectric cells
how to photoelectric cells work to protect building openings?
installed around building openings (e.g. doors), can detect intrusion when light beam is broken
what is area protection?
security by alerting of an intruder’s presence within the building; if perimeter systems fail, sensors placed in rooms can be triggered by a person moving or making noise within a space
which form of area protection has the least amount of coverage?
ultrasonic
can be effective by triggering building alarms when the high frequency sound wave they produce is disrupted; limited to a space not much larger than a standard 2 car garage (20x30)
what kind of security protection would a car alarm be considered?
object protection
sounds an alarm when the car is touched or handle attempts to be opened
what is typically required for building wiring in order to reduce the risk of fire?
conduits
protect cables & wiring, also limits exposure to harmful gases that may be emitted from the cables
how do you calculate the elevator speed required based on the building height?
1.6 x building height x 350
in feet per minute
e. g. if a building is 50’ high
1. 6 x 50’ x 350 = 430 ft/min.
what is the difference between a hydraulic elevator and a standard electric elevator?
hydraulic = plunger arm beneath the passenger car, pushes up
electric = wire cables & pulleys
what is a general size & capacity of an elevator car?
typical elevator cars for low rise buildings are rated at 2,500 lb and 5’x7’ in area
what is an ionization detector?
- sense particles of combustion in early smoldering stage before flames are present
- considered early warning
- not applicable where fires may produce a lot of smoke (dont detect this)
what type of fire alarm will detect the presence of smoke?
photoelectric
sensor light on device is obstructed by smoke present within a space; required as life safety devices since smoke inhalation is usually more lethal than the actual fire itself
what is a disadvantage of using a fire detection system that responds to changes in temperature?
flames generally need to be present, not much advanced warning
what are the requirements for fire detectors according to building code?
fire detection devices:
- in all sleeping rooms such as hotel rooms or bedrooms
- all places of public assembly
fire dampers:
- locate within mech. system so smoke is not allowed to circulate through building
which fire detection system is most commonly used in buildings?
combination smoke/fire detection
name 4 types of fire detection devices
- ionization
- photoelectric
- rise of temperature
- infrared flame detector
- ultraviolet flame detector
when architects & designers use windows & skylights to bring daylight into a space it is called:
daylighting
there are 2 kinds of lighting to consider when planning the lighting of a space:
- natural light
- artificial light
a system that uses a shallow pool of water on the roof during the day to absorb the sun’s energy; insulated covering placed over it at night to keep absorbed heat from escaping
roof pond system
a massive element capable of absorbing heat when needed and providing for later use when ambient temperatures are cooler is referred to as:
thermal mass
the greatest potential for heat gain & heat loss in a building (not considering infiltration) comes through where?
windows
in cold climates, to take advantage of low solar angles in the winter to collect heat in thermal mass in the building, it is best to have large windows facing which direction?
south
this type of light output points all the light in the direction of the task
direct
this type of light output throws all the light toward a reflective ceiling to illuminate a room
indirect
the largest likely impacts on electric lighting requirements & design for a building are derived from:
- orientation
- ceiling height
- massing
- section profiles
(determine daylight availability in building)
the calculated amount of illumination on a surface is called a:
footcandle (FC)
what is the difference between luminance and illuminance?
luminance = measurement of how bright light is (leaving) a surface, depends on reflectivity or transmittance
illuminance: the density of luminous energy incident (falling) on a surface, expressed as lumens per unit area
what is a lumen (l)?
unit of luminous flux, measure of total amount of visible light emitted by a source
one lumen uniformly cast on 1 sq.ft. of area ceates an illuminate of 1 footcandle
the calculated lumen output per watt input is called:
efficacy
measure of energy efficiency
when direct lighting is used to produce clearly defined lighting levels in accordance with the light required to complete detailed work such as reading, writing, paperwork, experiments, it is called:
task lighting
this type of lighting is generally used for circulation & general lighting to offer a sense of space; similar to outdoor light experienced on overcast day, no sharp shadows, comes from all directions
ambient lighting
this type of lighting is used to provide illumination to pathways for exiting a space should an emergency arise
emergency egress lighting
define CRI
color rendition index
how closely a light source approximates daylight of same color temperature, & displays true color of an object
a unit used in lighting that comes complete with a lamp, reflector, refractor, housing, & electrical connection
luminaire
2 types of glare:
direct: a light source that causes interference/distraction with a visual task
reflective: when a light source is reflected from a viewing surface into the eye
critical zone for direct glare is in the area above a 45 degree from the light source
what does CFL stand for?
compact fluorescent lamp
self-contained ballat, can be used in place of incandescents
a 2-lead semiconductor lighting device that is energy efficient, long life, can create bright white light w/ no heat output
LED
light-emitting diodes
the maximum CRI rating is ___
100
what are the 4 types of electric light sources?
- incandescent
- fluorescent
- high intensity discharge (HID)
- light-emitting diodes (LED)
this type of lamp consists of a tungsten filament that is sealed in a glass bulb containing heat & inert gas
incandescent
a few disadvantages to using incandescent lamps are:
low efficacy, short lamp life, high heat output
what is a tungsten halogen?
- type of incandescent in which filament is located within an inner quartz envelope
- can tolerate higher operating temperatures & contains a special halogen gas
- only slightly more efficient than regular incandescent bulb
these tubes produce light when an electrical current passes through gases inside the glass tube
fluorescent
name 2 types of lamps that have a reflective coating integrated into the lamp
- reflector (R)
- parabolic aluminized reflector (PAR)
increases efficiency of lamp, more precise beam control
the 3 types of fluorescent lamps are:
preheat, instant start, rapid start
a device that limits the starting & operating voltages to a lamp & controls the current once the lamp is operating is called a:
ballast
the high intensity discharge (HID) lamp is a lamp within a lamp and is run at very high voltage… name 4 types
- mercury vapor
- metal halide
- high pressure sodium
- low pressure sodium
this type of HID lamp is only considered suitable for street and security lighting because it produces a monochromatic yellow light and no color rendering
low pressure sodium
name a few advantages of using incandescent lamps
inexpensive, compact, dimmable, warm color rendition
what is the difference between dampproofing & waterproofing?
dampproofing: control of moisture that is not under hydrostatic pressure, typ. at protection of slabs & foundation walls below grade
waterproofing: control of moisture & water that is subject to hydrostatic pressure, may include protecting structures below water table
waterproofing is more difficult, need continuous seals
name 5 materials commonly used for moisture protection in buildings
- admixtures: added to concrete to repel water
- bituminous coatings: asphalt or coal-tar pitch applied to exterior of foundation wall
- cementitious coatings: portland cement mortar troweled over surface of foundation wall
- membranes: built-up layers of hot or cold-applied asphalt felts
- plastics: generally for above grade dampproofing
define hydrostatic pressure
pressure exerted by a fluid at equilibrium due to the force of gravity
for a retaining wall, any groundwater behind the wall that is not dissipated by a drainage system causes hydrostatic pressure on the wall
how can thermal expansion affect the design of a building?
tendency of matter to change in temperature
in general, most substances expand when heated and contract when cooled; can cause structural & aesthetic issues
when does water contract?
when hot, boiling water
when does water expand?
when cold or frozen
what is the difference between a retention and detention basin?
retention = manage stormwater runoff, prevent flooding & erosion, always contains water
detention = overflow to manage stormwater when other basins are full, always dry except during storms
the single best way to reduce reliance on the HVAC systems, and thus reduce energy consumption & operating costs is:
providing appropriate building assemblies
what is R-value?
a building material’s resistance to heat transmission, based on time it takes for 1 btu of heat to transfer through a material
typical R-values for temperate climates are ____ for roofs & ____ for exterior walls
roofs: R-30
walls: R-19
the fact that something is a good conductor means it offers little _____
resistance
what is the difference between conductivity (k) & conductance (C)?
k = measure of heat loss based on one sq.ft. of material 1” thick
c = based on other material thicknesses
what is the difference between conductivity (k) & conductance (C)?
k = measure of heat loss based on one sq.ft. of material 1” thick
c = based on other material thicknesses
C (conductance) and R (resistance) will always be inverse of each other. if C = 0.5, then R = ?
R = 1/C R = 2
what is permeance?
the ability of a building material to resist water vapor
place a vapor barrier on the side of the insulation where it tends to be ____
warmest
a temperature at which water vapor is not condensing into water any faster than water would be vaporizing into the air is known as the:
dew point
one way to actively guard against vapor turning into water inside walls is to use insulating materials such as:
closed cell foam
crawl spaces (btw. earch & underside of floor) should have a _____ to prevent moisture from coming up through the floor
moisture barrier
what items is an architect responsible for evaluating during SD per AIA B101?
- owner’s program
- schedule
- budget (cost of work, project site, & proposed delivery method)
what is the importance of considering construction sequencing?
helps reduce cost & unexpected delays to the construction schedule
on a construction job, who controls construction and the order in which the various trades perform their work?
the contractor
which elements are required on the site plan during design development?
- placement of building in relation to site
- streets, propertly lines, easements, setbacks, parking
- survey required
- civil engineer reviews grades, provides recommendations
what should be included on the building floor plans during DD?
- scaled plans
- structural grids
- critical elements & dimensions
- major building systems reflected, incl. shafts & equip. rooms
- perimeter laid out w/ door & window locations
how should the mechanical & electrical systems in a building be defined & developed during DD?
mechanical:
- reflected on plans
- outline specs & prelim. equip. lists
- distribution & riser diagrams
electrical:
- outline specs
- distribution diagrams
- room lighting layouts & ceiling plans
what is the difference between permeable & pervious?
permeable - capable of being penetrated by water without causing rupture or displacement
pervious - permitting leakage or flow of water through cracks, leaks, or other openings
define damp proofing
control of moisture that is not under hydrostatic pressure
name 4 types of damp proofing
- admixtures
- bituminous coating
- cementitious coating
- membranes
the 3 methods of heat transfer are:
- conduction = flow of heat within a material or between materials without displacement of the particles of the material
- convection = transfer of heat within fluid (gas or liquid) by movement from one area to another
- radiation = transfer of heat energy through electromagnetic waves from one surface to another
what is a BTU?
amount of heat required to raise the temperature of 1 lb of water by 1 degree F
what does XEPS mean?
extruded expanded polystyrene
closed cell material manufactured by mixing polystyrene pellets w/ chemicals & blowing agent, then forced through an extruder
higher insulative value per unit thickness & higher compressive strength than does MEPS
what are ICFs?
insulated concrete forms
interlocking foam insulation that serve as forms for pouring concrete walls, remain in place after wall has cured
when would the term mothballing be used?
historic preservation term; certain areas of building are closed up so they can be repaired & restored at a later date/phase
what is design intent as relates to preparing CDs?
desire to meet programmatic requirements; continually check the development of CDs against this
what is structural integrity as relates to preparing CDs?
provide for ability of project to withstand lateral forces by detailing connections to resist moment stresses, openings to resist suction, etc.
what is thermal control in regards to preparing CDs?
provide for control of heat gain/loss through use of insulation awnings, siting, etc…. also allow for thermal expansion & contraction w/ joints
what is water & moisture control in regards to preparing CDs?
preventing water penetration at roof, horiz/vert surfaces, protect from flooding
what is water & moisture control in regards to preparing CDs?
preventing water penetration at roof, horiz/vert surfaces, protect from flooding
what are 2 common materials used in the 1970’s but are now banned?
- asbestos
2. lead paint
in regards to preparing CDs. what is aethetics?
control design & aesthetics through review of shop drawings, product data, samples, mockups
in regards to preparing CDs, what is security?
protection against theft, vandalism, crime
in regards to preparing CDs what is environmental control?
durable materials that resist decay & corrosion, prevent insects from entering, prevent sick building syndrome
in regards to preparing CDs, what is acoustical control?
control unwanted noises
in regards to preparing CDs, what is life safety & accessibility?
structurally safe, meet requirements for life safety NFPA 101, & requirements for barrier-free provisions (ANSI / ADA)
in regards to preparing CDs, what is compliance w/ codes & regulations?
comply with all codes
in regards to preparing CDs, what is cost?
up-front cost, overhead, lifecycle cost
x
x
what form would be part of the bidding requirements?
- invitation to bid
- prequalification forms
- instructions to bidders
- information available to bidders
- bid forms
what could be some of the supplements to bid forms?
- bid security form
- subcontractor list
- substitution list
what forms could be included as part of the contract between owner & contractor?
A101 owner-contractor agreement
A312 performance bond & payment bond
certificates of insurance
what information is contained in the project manual?
- specifications
- conditions of the contract for construction:
- general conditions
- supplementary conditions
- other conditions - invitation to bidders / instructions to bidders
- bidding requirements
what is a reference specification?
- requires that a product, material, or system meet an established & recognized standard (e.g. UL, ASTM, ANSI)
- often used only for certain parts of project (e.g. mech/elec)
- benefit = any system is allowed so long as it meets the requirements of the standard
what is a descriptive specification?
- describes all components, materials, products, their arrangement, method of assembly, physical & chemical properties, etc.
- difficult to produce, substantial liability risks
what is a cash allowance?
used when final selections or design decisions have not yet been determined
helpful for preliminary bids
define the 2 different types of proprietary specifications
- open - includes 3 or more trade names with provision “or approved equal”
- closed - single trade name, doesn’t allow substitution (not allowed on public projects)
what is a performance specification?
- requires products, materials, or systems that must meet certain requirements
- similar to reference spec. but doesn’t name a testing standard, instead asks for a desired result (e.g. R-13 insulation in a 6” wall)
- innovation
what is the CSI MasterFormat and how is this reference helpful in project design?
used for materials classification, includes information & descriptions of products for performance requirements, quality standards, submittal requirements, warranties, delivery/storage, installation, and maintenance
helpful as a source for material specs when choosing them during design
what is the difference btw. coordinating & managing?
coordinating: sending door & window schedule & details to owner’s drapery consultant (part of scope of basic services)
managing: following up w/ owner’s drapery consultant to verify correct material has been ordered & scheduling install dates (as an additional service)
what is ASTM?
american society for testing & materials
develops & presents largest voluntary consensus standards for materials, systems, services, & products
what is NFPA?
national fire protection association
aims to reduce fire & other hazards through consensus codes, standards, education, & training; influence every building approval process & completion
e.g.
national electric code - NFPA 70
life safety code - NFPA 101
what is ANSI?
american national standards institute
helps ensure safety & health of life & protection of the environment
development of industry standards
what is UL?
underwriters’ laboratories
product safety certification; promote safety in environments w/ science & engineering
what is FM Global?
factory mutual
world’s largest insurance/risk management org. specializing in property protection
name 3 examples of construction assembly tests
ASTM 119 - building construction & material
- evaluates an assembly’s ability to prevent passage of fire, heat, & hot gasses
- 1-4 hr rating for walls
- 20/30/45 min for doors & other assemblies
NFPA 252 - door assemblies
- fire test for doors
NFPA 257 - window & glass block assembly
- fire & hose stream test
name 3 examples of construction material tests
ASTM E84 - steiner tunnel test
- surface burning characteristics of material
- flame spread rating
- class A (I), class B (II), class C (III)
- class A (I) is most fire resistant
NFPA 265 - room corner test
- textile interior finishes
- 8x12x8 corner of room
NFPA 286
- contribution of wall & ceiling finish to fire growth
- materials other than textiles
ADA showers must be equipped with:
- fold-down seat
- showerhead w/ flexible hose
- grab bars
- no curb
what determines an accessory use area?
to be considered an accessory use area, an area can’t exceed 10% of the total floor area allowed by the height/area table
it does not need to be separated from the main area by a fire separation
e.g. small office inside a factory
what is an incidental accessory area?
similar to an accessory area, an incidental accessory area can’t exceed 10% of the total floor area allowed by the height/area table, but it DOES need to be separated from the main area by a fire separation
e.g. a linen closed on the same floor as hotel rooms
what is mixed use occupancy?
when occupancies in a building are too large to be considered incidental or accessory, then need to be considered mixed
what is model building code developed by the ICC?
IBC
what are the 5 steps for a building code analysis?
- determine occupancy group & load
- identify fire areas & separation requirements
- identify type of construction
- determine means of egress
- determine the system requirements
the need for fire supression system is based on:
- area of the building (larger areas have more requirements)
- the type of occupancy (larger groups of people in one area will have stricter requirements)
- the number of occupants
egress doors cannot be hidden or disguised & must be:
- readily distinguishable
- readily recognizable
- cannot be covered with mirrors or other reflective material
- cannot be concealed fabrics, decorations, or other similar material
what are the requirements of egress doors?
- must be pivoted or side-hinged, but always need 32” minimum clear width
- must swing in direction of travel when area served has occupant load of 50 or more, or if group H
- must not swing into a required path of travel by more than 7” (can recess to avoid this issue)
what are the 3 parts of an egress system?
- exit access
- exit
- exit discharge
how many exits must a building have, as a min., w/ more than 50 occupants?
two
what is considered a public way?
any street, alley, or land that is unobstructed from the ground to the open sky, that is permanently set for public use w/ clear width of at least 10’
exits must discharge to a public way
what is an ordinance?
a municipal law in addition to the standard building code
what are 4 broad fire safety issues to consider in building design?
- occupancy group & load
- fire zones
- type of construction
- floor area & height
the basic philosophies of seismic codes are:
- a building foundation situated on top of a fault is not expected to withstand a large earthquake
- all other structures near a fault are expected to resist
- should remain intact reasonably long enough for the occupants to exit quickly & safely
- some components of the structure may fail, but the structure must not collapse
what is NFPA 101 and how can this code effect building design?
life safety code
not legal, but standard that cities can adopt
addresses construction type, fire protection, proposed occupancy
what causes the greatest damage to buildings during an earthquake?
ground shaking
what are 3 basic performance requirements of a building during a fire?
- permit safe egress
- maintain structural integrity & limit fire spread
- limit damage & avoid collapse
can escalators be considered a stairway for the purpose of calculating path of egress?
no, unless specific things area added (sealing opening, add’l venting/sprinklers, etc.)
what is the allowable width of exits to count toward the minimum number of exits required?
determined by the occupancy of the floor, plus an allowance for the floors above
why can the location of doors have a significant effect on the design of a building?
- maximum egress distance of 250’
- accessibility/ADA req’s
- open in direction of travel
what is a fire tower?
a stair built from non-combustible construction & connected w/ mechanically vented vestibules
required in buildings of 75’ or taller
what fire precautions are required for the ventilation system?
- minimize circulation of smoke by isolating ventilation for each fire area
what fire precautions are required for the ventilation system?
- minimize circulation of smoke by isolating ventilation for each fire area
- increase air pressure in fire tower by shutting top vented exhaust
what fire precautions are required for the ventilation system?
- minimize circulation of smoke by isolating ventilation for each fire area
- increase air pressure in fire tower by shutting top vented exhaust
what is panic hardware?
- push bar to open
- does not require a key, motion, or special knowledge
what are standpipes?
- required for buildings 3 or more stories
what are the 3 types of standpipe?
- wet
- dry
- combination
what are the 3 types of fire alarms?
- temperature sensor
- smoke detector
- combustion detector
flame spread ratings are divided into how many classes/categories?
5
A-E
unless local codes are stricter, all units of a 4+ unit residential building must have:
- accessible path from the entrance through the building & into the unit
- accessible light switches, outlets, thermostats, shower controls, etc.
- blocking in the bathroom walls to allow future installation of grab bars if needed
- kitchens & bathrooms can be used by a person in a wheelchair
the architect’s estimates are budgetary projections and typically do not include:
- market conditions
- inflation & cost of goods & services
- contractor means & methods of construction
- unknown site conditions
what is depreciation?
a federal tax benefit based on the idea that a building loses value as it ages
what is a general obligation bond?
when the state or local government wants to raise money for a project, the issue this type of municipal bond
shareholders are guaranteed to be repaid using future tax revenues
what is a revenue bond?
type of municipal bond, but rather than being repaid by taxes, the shareholders are promised payment from the revenue collection of the project (e.g. tolls from a bridge)
not as secure as a general obligation bond, so they offer a slightly higher interest rate
what is a pro-forma?
a financial analysis of the building project showing costs and ROI
done by client at beginning of project
what items are part of the project development budget?
- site acquisition & purchase
- construction
- off-site (utilities to property)
- on-site (10-20% of construction cost)
- building cost - professional services
- misc. fees (bids, permits, reports)
- inspection & testing
- contingencies (5-10%)
- financing costs (interest, fees, insurance)
what are contingencies?
a number added as a fixed percentage to the project cost, allow for unknowns
what is a GMP?
guaranteed maximum price
provided by contractor, if the drawings change, triggers a change order
what are the 5 main phases of project delivery according to AIA B101?
SD DD CD Bidding & Negotiation Construction Phase Services
name 4 ways an architect can estimate the cost of a project
- cost per sq.ft.
- cost per unit
- comparable buildings that are similar in function or located in same region
- historical data from similar projects architect has done
what is the critical path method?
schedule that assigns tasks (arrows) & times (circles mark start & finish) to every part of the construction
important events are called milestones
what are 3 ways to speed up or shorten the project schedule?
- overtime
- hire additional people
- reduction of man hours (quality can suffer)
