Structural all Flashcards
1
Q
what is the definition of dead loads
A
loads that are permanent in both magnitude and location throughout the intended life of the structure
2
Q
where are the minimum design DL found
A
ASCE 7 Table C3-1
3
Q
where are minimum material densities found
A
ASCE 7 Table C3-2
4
Q
what is the definition of live loads
A
max expected loads based on the intended use or occupancy
5
Q
where are min LL found
A
ASCE 7 Table 4.3-1 or IBC Table 1607.1
6
Q
a concentrated load is assumed to be distributed over an area of __ x __
A
30” x 30”
7
Q
what is the definition of a one way slab
A
aspect ratio >=2
8
Q
(YAY! inclusive; therefore, easier)
A
9
Q
what is the definition of a two way slab
A
aspect ratio < 2
10
Q
(YAY! exclusive; therefore, easier)
A
11
Q
what is the definition of statically determinate
A
when ALL the forces can be determined from just equilibrium equations
12
Q
what is the definition of statically indeterminate
A
structures having more unknown forces than available equilibrium equations
13
Q
what is a beam/column system with simple beams
A
space frame
14
Q
how to tell if a structure is determinate
A
R = 3n
15
Q
where R = unknown forces
A
16
Q
n = parts (i.e. cuts)
A
17
Q
how many unknowns are at a cut
A
1 because they are equal and opposite reactions
18
Q
how to determine the degrees of indeterminacy
A
R - 3n
19
Q
how to tell if a structure is indeterminate
A
R > 3n
20
Q
where R = unknowns
A
21
Q
n = parts (i.e. cuts)
A
22
Q
how to tell if a structure is unstable
A
R < 3n
23
Q
OR
A
24
Q
R >/= 3n AND lines of all reactions intersect at a point OR lines of all reactions are parallel
A
25
Exam Q: find shear and moment at point x
1. Is there a formula in AISC or handbook?
26
2. If not (or to check your work), make a cut at point x and solve for V and M
27
where are shear, moments, and deflection formulas and diagrams found
AISC Table 3-23 or handbook 4.1.7
28
how many equilibrium eqs are there available for a truss joint? what are they?
2 (Fx and Fy)
29
how to tell if a truss is determinate
M+R=2J
30
where M is # of members
31
R is # of reactions
32
J is # of joints
33
how to tell if a truss is indeterminate
M+R>2J
34
where M is # of members
35
R is # of reactions
36
J is # of joints
37
how to tell if a truss is externally unstable
1. reaction lines of action are all parallel
38
OR
39
2. reaction lines of action intersect at a common point
40
(same as beams)
41
how to tell if a truss is internally unstable
no restraints between diagonal joints (diamond = unstable; triangle = stable)
42
how to identify zero force truss members
1. two non-collinear members form a joint with no external loading or support reactions acting on the joint -> both members are zero force
43
2. three members form a joint for which two of the members are collinear and no external loading or support reactions are acting on the joint -> the third member is zero force
44
3. inspection (i.e. use equilibrium eq's to determine if there are no vert or horiz forces acting on a joint)
45
4. Two non-collinear members frame into a truss joint, and there is a load or support reaction that is collinear with one of the members -> the non-collinear member is a zero force member
46
how to analyze a truss with a distributed load applied to it
1. find force at each joint in contact with the distributed load with trib lengths
47
2. use method of joints or sections to find forces in members
48
when to use method of joints
member in question is close to the supports
49
when to use the method of sections
member in question is far from the supports
50
to use method of joints, you MUST __
chose a joint that has:
51
at most 2 unknown forces
52
at least 1 known force
53
to use method of sections, you MUST __
cut your section so that you have at most 3 unknown forces
54
steps in method of sections
1. find reactions
55
2. sum moments about intersecting members to find the third member force
56
3. if two members are parallel, sum the forces in the parallel direction
57
why do zero force members exist
stability of the truss during construction OR to provide support if the applied loading changes OR to brace a member (smaller unbraced length)
58
what is Hooke's Law
stress = Elastic modulus * strain (flexural and shear stress/strain)
59
where to find definition of Poisson's ratio
handbook 1.6
60
what is axial rigidy
EA (lb, kips)
61
what is the stiffness factor definition and formula
force required to produce a unit change in length
62
k = EA/L
63
what is the flexibility factor definition and formula
change in length produced by a unit force
64
f = L/EA
65
what is the basic deflection formula
defl = P/k OR defl = f*P
66
axial strains change member ___
length
67
shear strains change member ___
shape
68
what is the axial stress due to an axial force applied at an angle
sigma = P/A * cos^2(theta)
69
what is the shear stress due to an axial force applied at an angle
tau = P/A * sin(theta)cos(theta)
70
what is the relationship between lateral deflection and shear angle
delta = gamma * height of shear cross section
71
in temporary bracing problems, how to know which component of diagonal brace to find
find the component that counteracts the applied force (usually horizontal)
72
in bearing pad shear problem, what is the height in the equation lateral displacement = angle of shear * height
the bearing pad thickness
73
in bearing pad shear problem, what is the area in the shear stress equation
the cross sectional area of the face that the shear is applied to
74
what is the definition of curvature
a measure of how sharply a beam is bent
75
what is the formula for curvature
curvature = 1 / radius of curvature
76
what is the definition of the neutral axis
no change in length and stress/strain = 0
77
how are axial strain and curvature related
strain = distance to the neutral axis * curvature
78
how are axial stress and curvature related
stress = Elastic modulus * distance to the neutral axis * curvature
79
how are curvature and moment related
curvature = M/EI
80
what is the formula for flexural rigidy
Elastic modulus * moment of interia
81
for a beam subjected to bending moments, where is the neutral axis
the centroid of the cross section
82
what is the d in the parallel axis thm
d = distance from centroid of area 1 - centroid of full cross section
83
(or reverse... whichever is larger goes first... just have to make sure you are measuring from the same reference point... usually the top or bottom of the cross section)
84
which of the following parameters most affects the stress variation in a composite beam:
85
a) y: distance from NA
86
b) E: modulus of elasticity
87
c) Fy: yield stress
88
d) b: width of the section
b
89
t/f y (distance from neutral axis) affects the stress variation in a composite beam
t
90
t/f b (width of section) affects the stress variation in a composite beam
t
91
t/f there is no shear stress when moment is constant
t
92
t/f shear stress (tau) is developed at a vertical when bending stress varies
f, shear stress (tau) is developed at a HORIZONTAL when bending stress varies
93
To calculate shear stress (tau), you must find the 1st moment of area above or below the point where shear stress is to be determined (Q). What is d in the equation Q = A * d?
d = the distance from the neutral axis to the area centroid
94
To calculate shear stress (tau), you must find the 1st moment of area above or below the point where shear stress is to be determined (Q). What is A in the equation Q = A * d?
A = the area above the layer (or plane) upon which the desired transverse shear acts
95
t/f the shear stress in a rectangular cross section varies parabolically throughout the whole depth
t
96
t/f the shear stress in a wide flange cross section varies parabolically throughout the whole depth
f, shear stress through the flanges is much less than the shear stress through the web (bc smaller width)
97
what is the equation for max shear stress (tau) in a rectangular cross section
tau_max = 3/2 * (V/A)
98
(i.e. max tau is 50% more than average tau)
99
what is the equation for average shear stress (tau) in a rectangular cross section
tau_avg = V/A
100
what is the equation for max shear stress (tau) in a circular cross section
tau_max = 4/3 * (V/A)
101
how should you find the area or shear stress of a hollow cross section
larger area - smaller area
102
larger tau - smaller tau
103
where does the max shear stress (tau) occur along the depth of the cross section
the neutral axis
104
t/f the max shear stress (tau) occurs at the centroid of the cross section
f, the max shear stress (tau) occurs at the NEUTRAL AXIS of the cross section
105
where is the neutral axis along the depth of the cross section
where flexural stress = 0
106
(opposite of max moment along member = 0 shear)
107
where does max moment occur along the length of a member
where shear = 0
108
where does max shear stress occur along the depth of a cross section
where flexural stress = 0
109
how to find moment of inertia (I) and the first moment of area above or below the point where shear stress is to be determined (Q) of complicated cross sections
break the cross section into areas
110
what is the definition of shear flow
the horizontal shear force per distance along the longitudinal axis of the beam (lb/ft, k/ft, etc.)
111
where is shear stress to be determined when finding shear flow (i.e. what Area to use when finding Q)
area above or below the CONTACT SURFACE (i.e. location between shear planes / the attachment location)
112
shear flow = VQ/I =
capacity of fastener(s) / spacing
113
what is the width (b) when calculating shear stress at the midpoint of a tube with 1/2" thick walls
1"
114
(1/2" * 2 = 1")
115
what is the moment of inertia (I) when calculating shear flow
the moment of inertia of the FULL cross section NOT just of the area used for Q
116
t/f strain in composite members has a discontinuity at the change in material
f, stress in composite members has a discontinuity at the change in material
117
t/f stress in composite members has a discontinuity at the change in material
t
118
where is the neutral axis in beams with eccentric axial load
y_NA = I / (A*e)
119
t/f for composite members always convert the __ to the __
strong to the weak (in handbook, in description OR just remember stronger material gets larger width)
120
for combo loading, take A as area above __
neutral axis
121
for combo loading, take I about __
centroid of cross section
122
for beams with eccentric axial loads, NA is BELOW the centroid when eccentricity (e) is __
pos
123
(NA is opposite of max stress)
124
for beams with eccentric axial loads, NA is ABOVE the centroid when eccentricity (e) is __
neg
125
(NA is opposite of max stress)
126
the discontinuity in stress along the depth of the cross section in composite members is due to __
modulus of elasticity (E)
127
where does the max torsion strain occur on the cross section
the outer surface
128
why are tubes better than wide flanges in torsion
the is material all along the outer surface where the max strain is located
129
in the torsional strain equation, what does d*phi/d*z equal
phi/L
130
what is the equation for torsional stiffness
GJ/L
131
what is the equation for torsional flexibility
L/GJ
132
what is the equation for rate of twist
phi/L
133
what member property MOST affects torsional resistance
J
134
what member property MOST affects flexural resistance
I
135
t/f a circle is better than a square in torsion
t
136
t/f a rectangle is better than a square in torsion
f
137
t/f a closed shape is better than an open shape in torsion
t
138
which of the following affects the strength of an axially loaded column the most:
139
a) radius of gyration
140
b) column height
141
c) slenderness ratio
142
d) column cross sectional area
c
143
what is the definition of axial buckling
excessive lateral deflection under axial compression
144
non-sway (braced) frame BEAMS resist (gravity only, lateral only, gravity and lateral) loads
gravity only
145
sway (unbraced) frame BEAMS resist (gravity only, lateral only, gravity and lateral) loads
gravity and lateral
146
what is the failure mechanism of short concrete columns
yielding of reinf or crushing of concrete
147
for what kind of columns must the buckling effect and slenderness ration be taken into account
long columns
148
what are (3) failure mechanisms of columns
1. strength (axial stress = P/A)
149
2. stiffness (deflection = PL/AE)
150
3. buckling (Euler's buckling formula)
151
is a partially saturated soil sample (above/below) the GW table
above
152
a partially saturated soil sample contains which of the following (can be combo): solids, water, air
solids + water + air
153
is a fully saturated soil sample (above/below) the GW table
below
154
a fully saturated soil sample contains which of the following (can be combo): solids, water, air
solids + water
155
a dry soil sample contains which of the following (can be combo): solids, water, air
solids + air
156
t/f the voids in fully saturated soils contain water only
t
157
t/f the voids in dry soil samples contain water only
f; contain air only
158
a sieve analysis is done for (coarse/fine) aggregates
coarse
159
a hydrometer analysis is done for (coarse/fine) aggregates
fine
160
how does a hydrometer analysis determine particle diameter
uses the principle of sedimentation to determine settlement velocity and Stoke's Law to relate velocity to particle diameter
161
which sieve number separates gravel and sand
#4
162
which sieve number separates coarse agg and fine agg
#200
163
what does the sieve number represent
# of openings per square inch
164
the lateral strain required to fully mobilize the soil (active/passive) pressure is (slightly/considerably) (smaller/larger) than the lateral strain to fully mobilize the (active/passive) pressure
passive, considerably, larger, active
165
when designing a basement retaining wall supported by a floor at the top of the basement wall, which lateral earth pressure coefficient should be used
at rest
166
which of the following factors will affect the determination of the lateral earth pressure coefficients using Rankine:
167
a) backfill slope (BETA)
168
b) internal friction angle (phi)
169
c) water table
170
d) both a and b
d
171
which of the following factors will affect the determination of the lateral earth pressure coefficients using Coulomb (choose all that apply):
172
a) internal friction angle (phi)
173
b) soil wall friction value (delta)
174
c) backfill slope (beta)
175
c) wall slope (theta)
all of the above
176
how can you increase a retaining wall FS for sliding
1. add a key (engages passive earth pressure)
177
2. increase weight
178
how does a key help reduce sliding
engages passive earth pressure
179
t/f multiply pore water pressure (u) by earth pressure constant (K) to get lateral pressure (p)
f
180
t/f multiply soil vertical pressure (sigma'_v) by earth pressure constant (K) to get lateral pressure (p)
t
181
t/f multiply surcharge (q) by earth pressure constant (K) to get lateral pressure (p)
t
182
what is the use of effective vertical stress (sigma'_v)
case for if pore water escapes
183
what controls soil failure (vertical or shear) stress
shear
184
what earth pressure should be used for a case where a wall has no movement
at rest
185
what earth pressure should be used for a case where a wall moves away from the soil
active
186
what earth pressure should be used for a case where a wall moves into the soil
passive (passes into the soil)
187
what is an example of when the at rest earth pressure is appropriate
basement walls, rigid retaining walls, culverts, "negligible movement"
188
what is an example of when the active earth pressure is appropriate
retaining walls
189
what is an example of when the passive earth pressure is appropriate
soil over toe on a retaining wall (if you consider this, you should use FS=2.0 for sliding and overturning)
190
t/f cohesion (clay) counteracts applied force (creates a reaction of opposite direction than applied force)
t (clay pushes back)
191
for pure clay (phi = 0) what does active earth pressure (Ka) =
1
192
for pure clay (phi = 0) what does passive earth pressure (Kp) =
1
193
how does active earth pressure relate to passive earth pressure
Ka = 1/Kp
194
what type of soil does not have internal friction (phi)
clay
195
what type of soil does not have cohesion (c)
sands/gravels
196
What is the factor of safety for sliding and overturning? What changes the typical value?
1.5, use 2.0 if passive pressure is utilized
197
what are the failure modes for retaining walls
1. sliding
198
2. overturning
199
3. bearing
200
how can you increase sliding factor of safety (FS)
1. add a key (engages passive pressure)
201
2. add weight
202
how does a key reduce sliding factor of safety (FS)
engages passive pressure
203
what is a material's ability to undergo large inelastic deformation without fracture
ductility
204
what is a material's ability to absorb energy
toughness (think black panther)
205
what material property determines the material's capability to resist deterioration from the adverse environment conditions, chemical attack, and abrasion (wear and tear) while maintaining its desire physical prperties
durability
206
t/f using larger well-rounded and smooth aggregate instead of smaller irregular shaped aggregate particles enhances the concrete workability
t
207
t/f coarse aggregates should be reactive with cement
f; non-reactive
208
t/f coarse aggregates should be retained in sieve #3
f; sieve #4
209
t/f coarse aggregates are mixed with cement and water to form the cement paste
f; only cement and water are mixed to form the cement paste
210
t/f coarse aggregate used in concrete should be free of any impurity and organic matters
t
211
what is the chemical reaction between cement and water to form a chemical bond
hydration process (heat of hydration)
212
t/f the hydration process in concrete creates heat
t
213
what is the ease of placing, consolidation, and finishing concrete
workability
214
what is the property influencing the concrete's ability to flow
consistency
215
the slump test is related to which concrete property
consistency
216
what concrete property is related to the concrete's resistance to segregation
stability
217
what concrete property is related to how homogeneous the mixture is
uniformity
218
what is the term for if concrete is not uniform
bleeding
219
what is concrete's property that resists strain or rupture induced by external forces
strength
220
what is concrete's property that resists weathering, chemical attack, abrasion, and other service conditions
durability
221
what is concrete's property that meets desired aesthetic characteristics
appearance
222
aggregates make up __ to __ % of concrete volume
60 - 75%
223
what is the unit weight of lightweight aggregate
90 - 120 pcf
224
what is the unit weight of heavy weight aggregate
180 - 380 pcf
225
if aggregate in concrete is too small,
more water and cement is required to mix ($$$)
226
if aggregate in concrete is too large,
honeycombing occurs
227
what is the equation for specific gravity (relative density) for concrete aggregate
ratio of the mass of the agg to the mass of equal volume of water
228
what is the definition of bulk density for concrete aggregate
mass of agg to fill a certain volume
229
what is the formula for particle density for concrete aggregate when given specific gravity of agg (SG)
SG * unit weight of water
230
what moisture condition do you want your aggregates for concrete to be at
saturated surface dry (SSD)
231
what is the definition of oven dry for concrete aggregates
zero moisture content (fully absorbant)
232
what is the definition of air dry for concrete aggregates
dry at particle surface, but containing some interior moisture (less than potential absorption)
233
what is the definition of saturated surface dry for concrete aggregates
neither absorbing water from, not contributing to the concrete water content (equal to potential absorption)
234
what is the definition of damp or wet for concrete aggregates
containing excess moisture or "free water" (greater than absorption)
235
which cement type should NOT be used for a multistory reinforced concrete building if the building needs to be put in use ASAP? why?
236
a) Type I
237
b) Type II
238
c) Type III
239
d) Type IV
type IV - has a low heat of hydration meaning it will take a long time to set
240
which of the following materials could be helpful admixture for concrete in cold regions.
241
a) air-entraining
242
b) retarding
243
c) accelerating
244
d) a or c
d
245
what inhibits the rusting of reinforcing steel when added to concrete mix
calcium nitrate
246
for a structural element with congested steel reinforcement you will use:
247
a) dry mix
248
b) super plasticizer
249
c) fly ash
250
d) fine materials
b
251
_____ is the most destructive environmental factor that deteriorates concrete?
252
a) bleeding
253
b) hot weather
254
c) freezing and thawing
255
d) segregation
c
256
what is type I cement used for
normal applications
257
what is type II cement used for
moderate sulfate resistance, seawater applications
258
what is type II (MH) cement used for
moderate heat of hydration and moderate sulfate resistance
259
what is type III cement used for
high early strength, cold weather
260
what is type IV cement used for
low heat of hydration, large structures
261
what is type V cement used for
high sulfate resistance
262
which cement type has another requirement that must be met in order to work correctly? what is the requirement
type II, low w/c
263
what are (5) examples of supplementary cementitious materials (SCM)
1. fly ash
264
2. slag cement
265
3. silica fume
266
4. natural pozzolans
267
5. ground glass
268
what is the purpose of supplementary cementitious materials (SCM)
to replace portions of traditional cement to enhance concrete properties in the fresh and hardened state
269
what is the purpose of air-entraining admixtures
improves durability w/ freeze thaw conditions
270
t/f air-entraining admixtures and entrapped air voids create the same outcome
f, not the same
271
what is the difference between air-entraining admixtures and entrapped air bubbles in concrete mix design
entrapped air bubbles are MUCH larger than the air voids from admixtures
272
t/f entrapped air voids in concrete is okay for the concrete
f, not ok
273
what is the purpose of water-reducing admixtures (plasticizers)
1. increase workability w/o decreasing strength
274
2. permits a decrease in w/c w/o decreasing slump
275
3. used in structural elements with congested steel
276
4. allows for a lower pumping pressure
277
when are set accelerating admixtures used
cold weather
278
when are set retarding admixtures used
1. hot weather
279
2. complicated placement
280
3. long hauls
281
when are extended-set control admixtures used
1. allows for reuse of concrete
282
2. long hauls
283
what are the two components of extended-set control admixtures
1. stabilizer: stops hydration
284
2. activator: re-establishes normal hydration
285
when are viscosity-modifying admixtures used
underwater applications
286
what applications are corrosion inhibitors used
1. parking garages
287
2. marine structures
288
3. bridges
289
chloride ions ___ corrosion
cause
290
nitrate ions ___ corrosion
fight
291
what are 5 ways to increase workability in concrete
1. increase w/c
292
2. use larger, well-rounded, and smooth aggregate
293
3. use non-porous and saturated agg
294
4. add appropriate admixtures and air-entraining admixtures
295
5. increase mixing time and temp
296
t/f hot weather increases water demand in concrete
t
297
t/f hot weather increases slump in concrete
f, decreases
298
t/f hot weather decreases the rate of setting in concrete
f, increases
299
t/f there is incomplete hydration in concrete placed in hot weather
t
300
t/f cold weather slows hydration in concrete
t
301
t/f cold weather speeds up hydration in concrete
f, slows down
302
t/f cold weather speeds up strength gain in concrete
f, slows down
303
t/f HSS are hot rolled
f, cold-formed (bend and weld seam)
304
t/f W-shapes are hot rolled
t
305
t/f rebar is hot rolled
t
306
what is the difference btwn pipes and HSS
grade (HSS = 42 ksi, pipes = 35 ksi)
307
which of the following statements is incorrect
308
a) reinforcement steel reduces the deflection of the concrete elements with large spans
309
b) reinforcement bars are added inside the concrete elements to strengthen the tensile strength of concrete
310
c) reinforcement steel does not increase the compressive capacity of the concrete members
311
d) reinforced concrete has better resistance to fire than structural steel
c
312
in steel manufacturing, different steel types with various properties can be produced by which of the following
313
a) changing the amount of carbon and other alloy content
314
b) changing the temp at production
315
c) increasing the ultimate strength
316
d) a & b
d
317
fatigue in steel is the result of
318
a) reduction in strength due to cyclical loading
319
b) presence of chloride ion
320
c) oxidization of the molten metals
321
d) excessive deflection under sustained loads
a
322
the stress level below which the material can withstand virtually infinite number of load cycles is designated as the ___
endurance limit
323
what are 6 uses for steel in reinf concrete than flexural strength
1. resist a portion of compression (reduce column size)
324
2. reduce long term creep deflections
325
3. resist diagonal cracks (stirrups, ties, hoops spirals)
326
4. resist internal pressures in circular structures (tanks, pipes)
327
5. crack control
328
6. provide confinement of conc to increase ductility
329
what are two ways we protect reinf from corrosion
1. cover
330
2. epoxy coating, zinc coating (galvanization), stainless steel reinf, fiber reinforced polymers (FRP)
331
t/f it is best practice to provide the bottom layer of rebar as coated and second layer as uncoated for economy
f, you cannot place coated and uncoated rebar in the same member
332
how is the prestressed force transferred for pretensioned concrete
through bond (tendons stressed, then conc poured)
333
how is the prestress force transferred for post-tensioned concrete
end anchor
334
if carbon is increased in steel, strength __
increases
335
if carbon is increased in steel, ductility __
decreases
336
if carbon is increased in steel, the ability to weld __
decreases
337
what is the purpose of heat treated steel? what is the trade-off
increase strength, less ductility
338
what is an example of heat treated steel grade
A325 (bolts)
339
structural steel shear strength is about __ of its yield strength
0.6
340
what portion of the structural steel stress vs strain curve is ductility represented
after yielding
341
where on the structural steel stress vs strain curve is toughness found
the strain at rupture
342
where on the structural steel stress vs strain curve is the toughness modulus found
the area under the curve
343
in structural steel, greater toughness = greater
ductility
344
t/f all structural steel grades have the same modulus of elasticity
t
345
why are inert gases introduced to arc welding
to protect the molten metals from the atmosphere so they do not oxidize and produce porous and brittle welds
346
what does the charpy v-notch test measure
toughness
347
how do you do the charpy v-notch test
striking a standard notched specimen with a controlled weight pendulum swung from a set height
348
in a fatigue test, you plot a stress vs. __ graph
number of cycles
349
what is the highest stress in a fatigue test stress vs number of cycles graph
ultimate strenght
350
what is the lowest stress in a fatigue test stress vs number of cycles graph
endurance limit
351
where is there no fatigue in a steel member
under the endurance limit on a stress vs no. cycles graph
352
which type of cement is most appropriate for a large dam (type II or type IV)
type IV
353
what should be used in highly congested reinf (type IV cement or high slump)
high slump
354
what type of retaining wall has lower sliding resistance (large toe and small heel OR very thin footing)
very thin footing
355
what is the difference between ASCE and IBC load combos
IBC has different factors for heavy LL and saw tooth roofs
356
what is the trib area for a two way slab
A_T = 1/2 * span * trib width
357
for a one way slab, the trib area must not be less than
A_T ≤ 0.5l^2 (IBC 1607.11.1.1) where l = span length
358
using the IBC alternative LL reduction method (1607.11.2), how do you find L after finding R
L = Lo * (1 - R/100)
359
t/f IBC code provisions are trying to design for a totally elastic structure with no damage during a major earthquake
f, minor earthquake: no damage (elastic)
360
moderate earthquake: non-structural damage, no structural damage
361
major earthquake: possible structural damage (inelastic), but NO collapse
362
how is energy dissipated during an earthquake (design philosophy)
designing and detailing certain pre-determined locations to deform inelastically (yielding)
363
if the secondary roof drainage system is overflow along a roof edge, then d_h = ?? when determining the rain load
0
364
what is the interpolation formula
(x2 - x)/(x2 - x1) = (y2 - y)/(y2 - y1)
365
stay afloat are keywords for what type of force
buoyant force
366
where can you find soil loading in psf
IBC 1610
367
where are occupancy classifications (referenced in IBC 1604.5 - risk category table) defined
IBC ch. 3
368
t/f for flat roofs, the minimum snow load (p_m) supersedes the flat roof snow load (p_f)
f, they are different cases
369
where are "slippery" roof materials defined
ASCE 7.1 and 7.4
370
what is the spectral response factor for SHORT buildings
Ss
371
what is the spectral response factor for TALL buildings with LONG periods
S1
372
what is the default site class
site class D
373
what seismic design coef/factor represents the ability of a structural system to resist lateral loads without collapse? another def: is used to reduce the seismic force from the level of the elastic force that would have developed in a fully linear response (elastic structure with no damage) to prescribed force level (design force) that would yield the structure and utilize the nonlinear energy absorption in the system
the response modification coef (R)
374
what seismic design coef/factor represents the actual strength of the structure compared to the design seismic force
overstrength factor (OMEGA)
375
what are (6) reasons the overstrength factor (OMEGA) is necessary in seismic force calculations
1. conservative design methods
376
2. system redundancy
377
3. material overstrength
378
4. oversized members
379
5. load factors
380
6. drift limits controlling design
381
what seismic design coef/factor penalizes the structures with relatively few lateral load resisting elements (increases the demand on less redundant systems)
redundancy factor (rho)
382
what type of site does the mapped MCE_R acceleration parameters assume? how do we adjust for site class effects
rock; multiply by the site coefficient (Fa or Fv)
383
what risk category is a wastewater treatment plant that is not used for emergencies
III
384
is a dual system building with special moment frame and steel eccentrically braced frame "eccentrically braced frame" or "all other building systems" in the table used to find the approximate period of a structure
eccentrically braced frame (fits D1)
385
a very redundant system has rho = ??
1
386
a system that does not have much redundancy has rho = ??
1.3
387
bearing walls lateral force resisting system contains vertical walls that carry (both gravity and lateral loads OR only lateral loads)
BOTH gravity and lateral loads
388
building frame lateral force resisting systems contain vertical walls and braced frames that carry (both gravity and lateral loads OR only lateral loads)
ONLY lateral loads
389
flexible diaphragms distribute load by __
trib widths
390
rigid diaphragms distribute load by __
rigidity / stiffness
391
how do flexible diaphragms deflect
like simple beams
392
how do rigid diaphragms deflect
like a flat plate
393
how to find the shear force in a wall attached to a flexible diaphragm
Vw = Rd [lb] OR qw = Rd / bw [plf]
394
where Rd = reaction from diaphragm idealized as a simple beam
395
bw = length of wall
396
how to find the shear force in a wall attached to a rigid diaphragm
1) Find the total load on the diaphragm
397
2) Find the total rigidity / stiffness
398
3) Vw = total load * (rigidity at that wall / total rigidity)
399
if walls have openings, how to distribute the wall shear from diaphragm to each wall segment
1. if walls are flexible -> distribute by wall length
400
2. if walls are rigid -> distribute by rigidity ratio
401
the diaphragm chord is (parallel / perpendicular) to lateral load
perpendicular (like tension and compression chords of beam)
402
how to find the forces in the diaphragm chords
T = C = M/d (like a T/C couple)
403
wind loads on structures are primarily related to wind (speed or acceleration)
speed
404
seismic loads on structures are primarily related to seismic (speed or acceleration)
acceleration
405
MWFRS contribute to the ...
overall building stability
406
what are some examples of MWFRS elements
frames, cross bracing, columns, shear walls
407
cladding receives wind load __
directly
408
what are some examples of cladding
wall and roof sheathing, curtain walls, windows doors
409
components receive wind load from __ and ....
cladding and transfer it to MWRFS
410
what are some examples of components
purlins, studs, girts, fasteners, roof trusses
411
the directional procedure calcs MWFRS wind loads in __ direction(s)
1
412
the envelope procedure calcs MWFRS wind loads in __ direction(s)
all
413
where is the MWFRS directional procedure found
ASCE 7 Ch. 27
414
where is the MWFRS envelope procedure found
ASCE 7 Ch. 28
415
since the main table for k_zt to calc wind velocity pressure (q_z) considers Exp C, how do you find k_zt for Exp B and D
use equations at the bottom of the table
416
what is the process for finding the axial force in a collector
1. Find q_d and q_w. Plot them on the same shear diagram
417
2. Plot the net shear diagram. Add the "+" q_d and the "-" q_w.
418
3. Integrate (i.e. find area under) the net shear diagram to find the axial force in the collector.
419
for MWFRS and C&C k_d =
0.85
420
what is the purpose of the gust effect factor
accounts for bldg pushing back against wind (sim to active pressure: retaining wall pushing against soil)
421
for flexible structures, what value does G have
G > 1.0
422
for rigid structures, what value does G have
G = 0.85
423
enclosure classifications affect...
the internal pressure developed inside a bldg
424
opening in a windward wall creates internal (pressure/suction)
pressure
425
opening in a leeward wall or roof creates internal (pressure/suction)
suction
426
t/f glazing that is not impact resistant must be considered an opening
t
427
where to find opening definitions
ASCE 26.2
428
low rise bldgs are (flexible, rigid)
rigid (k_d = 0.85)
429
what is the definition of a low rise bldg according to ASCE 7
the mean roof height is < 60' AND h ≤ the least horiz dim
430
t/f diaphragm flexibility definitions are the same for seismic and wind loads
f (check ASCE 12.3 for seismic, and ASCE 26.2 for wind)
431
what is the purpose of the ground elevation factor (k_e)
reduces the wind velocity pressure due to higher elevations = less air density = less wind speed (NEW TO ASCE 7-16)
432
t/f the envelope procedure is applicable to all bldg heights and enclosure classes
f, directional procedure
433
t/f ice loads only apply to ice sensitive structures
t
434
t/f ice loads consider a circular area or cylindrical volume of ice around the structural shape, dome, flat plate, etc
t
435
what is the min ice density when calculating ice loads
56 psf
436
a frame is determinate if
3m + r = 3j + c
437
where m = # members
438
r = # reactions
439
j = # joints
440
c = # hinges
441
a frame is indeterminate if
3m + r > 3j + c
442
where m = # members
443
r = # reactions
444
j = # joints
445
c = # hinges
446
a frame is unstable if
3m + r < 3j + c
447
where m = # members
448
r = # reactions
449
j = # joints
450
c = # hinges
451
for shear diagrams: uniform load -> __ shear
linearly varying shear
452
for shear diagrams: zero load -> __ shear
constant shear
453
for shear diagrams: concentrated load -> __ shear
abrupt change in shear
454
for shear diagrams: triangular load -> __ shear
parabolic shear
455
for shear diagrams: how to tell if parabolic shear is concave up or concave down
max shear value = max slope
456
min shear value = min slope
457
for moment diagrams: constant shear -> __ moment
linearly varying moment
458
for moment diagrams: linearly varying shear -> __ moment
parabolic moment
459
for moment diagrams: abrupt change in shear -> __ moment
break in moment slope
460
for moment diagrams: parabolic shear -> __ moment
3rd order moment variation
461
for moment diagrams: how to tell if 3rd order moment variation is concave up or concave down
smallest absolute value of shear = smallest slope
462
largest absolute value of shear = largest slope
463
in the conjugate beam method, a REAL pin/roller support becomes a __ CONJUGATE support
pin/roller
464
in the conjugate beam method, a REAL fixed support becomes a __ CONJUGATE support
free end
465
in the conjugate beam method, a REAL free end becomes a __ CONJUGATE support
fixed
466
in the conjugate beam method, a REAL hinge support becomes a __ CONJUGATE support
interior support
467
in the conjugate beam method, a REAL interior support becomes a __ CONJUGATE support
hinge
468
what are the steps to the finding beam deflection by the conjugate beam method
1. determine the REAL beam's moment diagram
469
2. divide the REAL beam moment diagram by EI (M/EI diagram)
470
3. apply the M/EI diagram as loads on the CONJUGATE beam
471
4. to find REAL rotation, find CONJUGATE shear
472
to find REAL deflection, find CONJUGATE moment
473
what are the steps to finding beam or frame deflection by the virtual work method
1. determine the moment diagram due to the applied loads
474
2. determine the moment diagram due to the unit load
475
3. compute M(x)*m(x)
476
4. BEAMS: integrate M(x)*m(x)/EI(x) from 0 to L
477
FRAMES: sum the above formula for all frame members
478
what are the steps to finding truss deflection by the virtual work method
1. eliminate all zero force members
479
2. determine axial forces in members due to applied load (Pi)
480
3. determine axial forces in members due to the unit load (pi)
481
**i.e. divide the axial forces in members due to the applied load by the applied load**
482
4. sum Pi*pi*Li/Ai*Ei for all members
483
what is the max stress allowed when designing for fatigue in steel? under factored or service loads
0.66Fy, service
484
what types of structures does fatigue normally occur in
bridges, industrial facilities, offshore structures, anything else with cyclic loading
485
in the exam, if you are given a steel design problem asking about buckling, which k value should you use
recommended (AISC C-A-7.1)
486
in the exam, if you are given a general analysis problem asking about buckling which k value should you use
theoretical (handbook)
487
which gives adequate warning of impending concrete bending failure, a (tension or compression) controlled failure
tension controlled
488
what is the maximum concrete compressive strain
0.003
489
what is the purpose of the minimum flexural steel requirement in reinf concrete
To ensure that the flexural strength of the reinforced section is greater than that of the uncracked concrete section. This must be the case, or sudden failure will occur when the modulus of rupture of the concrete is exceeded and the first flexural crack forms.
490
how to solve a support settlement problem when all but 1 support has settled?
raise the one support that has not settled and treat like a normal support settlement problem
491
t/f forces are generated when a support settles on a determinate structure
f, indeterminate
492
t/f forces are generated when a support settles on a indeterminate structure
t
493
what is the definition of progressive collapse
a primary structural element fails, resulting in the failure of adjoining structural elements, which in turn causes further structural failures
494
to find an influence line for moment at a fixed support, the fixed support must be considered
pinned (remove the support's ability to resist moment)
495
what does a hinge do to deflection of a simply supported beam
causes deflection to change directions at the hinge
496
t/f to find the max beam (reaction, shear, or moment) apply the factored load in the positive region of the influence line
f, apply LL in the positive region but ALWAYS apply DL across the whole beam
497
why does rebar used in reinforced concrete have deformations in it
to create a strong bond between concrete and reinf
498
scenario: double stacked cantilever beams (opp ends fixed), how to find the force required to be applied at the top beam to deflect a point on the bottom beam?
1. separate into two individual beams
499
2. use the deflection eq's to solve for force required
